Thirty years of Medical Research Council randomized trials in solid tumours

Constructing Relative Effect Priors for Research Prioritization and Trial Design: A Meta-epidemiological Analysis

BACKGROUND

Bayesian methods have potential for efficient design of randomized clinical trials (RCTs) by incorporating existing evidence. Furthermore, value of information (VOI) methods estimate the value of reducing decision uncertainty, aiding transparent research prioritization. These methods require a prior distribution describing current uncertainty in key parameters, such as relative treatment effect (RTE). However, at the time of designing and commissioning research, there may be no data to base the prior on. The aim of this article is to present methods to construct priors for RTEs based on a collection of previous RCTs.

METHODS

We developed 2 Bayesian hierarchical models that captured variability in RTE between studies within disease area accounting for study characteristics. We illustrate the methods using a data set of 743 published RCTs across 9 disease areas to obtain predictive distributions for RTEs for a range of disease areas. We illustrate how the priors from such an analysis can be used in a VOI analysis for an RCT in bladder cancer and compare the results with those using an uninformative prior.

RESULTS

For most disease areas, the predicted RTE favored new interventions over comparators. The predicted effects and uncertainty differed across the 9 disease areas. VOI analysis showed that the expected value of research is much lower with our empirically derived prior compared with an uninformative prior.

CONCLUSIONS

This study demonstrates a novel approach to generating informative priors that can be used to aid research prioritization and trial design. The methods can also be used to combine RCT evidence with expert opinion. Further work is needed to create a rich database of RCT evidence that can be used to form off-the-shelf priors.

HIGHLIGHTS

Bayesian methods have potential to aid the efficient design of randomized clinical trials (RCTs) by incorporating existing evidence. Value-of-information (VOI) methods can be used to aid research prioritization by calculating the value of current decision uncertainty.These methods require a distribution describing current uncertainty in key parameters, that is, "prior distributions."This article demonstrates a methodology to estimate prior distributions for relative treatment effects (odds and hazard ratios) estimated from a collection of previous RCTs.These results may be combined with expert elicitation to facilitate 1) value-of-information methods to prioritize research or 2) Bayesian methods for research design.

PARP (Poly ADP-Ribose Polymerase) inhibitors for locally advanced or metastatic breast cancer

BACKGROUND

Locally advanced and metastatic breast cancer remains a challenge to treat. With emerging study results, it is important to interpret the available clinical data and apply the evidence offering the most effective treatment to the right patient. Poly(ADP Ribose) Polymerase (PARP) inhibitors are a new class of drug and their role in the treatment of locally advanced and metastatic breast cancer is being established.

OBJECTIVES

To determine the efficacy, safety profile, and potential harms of Poly(ADP-Ribose) Polymerase (PARP) inhibitors in the treatment of patients with locally advanced or metastatic breast cancer. The primary outcome of interest was overall survival; secondary outcomes included progression-free survival, tumour response rate, quality of life, and adverse events.

SEARCH METHODS

On 8 June 2020, we searched the Cochrane Breast Cancer Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE via OvidSP, Embase via OvidSP, World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) search portal and ClinicalTrials.gov. We also searched proceedings from the major oncology conferences as well as scanned reference lists from eligible publications and contacted corresponding authors of trials for further information, where needed.

SELECTION CRITERIA

We included randomised controlled trials on participants with locally advanced or metastatic breast cancer comparing 1) chemotherapy in combination with PARP inhibitors, compared to the same chemotherapy without PARP inhibitors or 2) treatment with PARP inhibitors, compared to treatment with other chemotherapy. We included studies that reported on our primary outcome of overall survival and secondary outcomes including progression-free survival, tumour response rate, quality of life, and adverse events.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures defined by Cochrane. Summary statistics for the endpoints used hazard ratios (HR) with 95% confidence intervals (CI) for overall survival and progression-free survival, and odds ratios (OR) for response rate (RR) and toxicity.

MAIN RESULTS

We identified 49 articles for qualitative synthesis, describing five randomised controlled trials that were included in the quantitative synthesis (meta-analysis). A sixth trial was assessed as eligible but had ended prematurely and no data were available for inclusion in our meta-analysis. Risk of bias was predominately low to unclear across all studies except in regards to performance bias (3/5 high risk) and detection bias for the outcomes of quality of life (2/2 high risk) and reporting of adverse events (3/5 high risk). High-certainty evidence shows there may be a small advantage in overall survival (HR 0.87, 95% CI 0.76 to 1.00; 4 studies; 1435 patients). High-certainty evidence shows that PARP inhibitors offer an improvement in PFS in locally advanced/metastatic HER2-negative, BRCA germline mutated breast cancer patients (HR 0.63, 95% CI 0.56 to 0.71; 5 studies; 1474 patients). There was no statistical heterogeneity for these outcomes. Subgroup analyses for PFS outcomes based on trial level data were performed for triple-negative breast cancer, hormone-positive and/or HER2-positive breast cancer, BRCA1 and BRCA2 germline mutations, and patients who had received prior chemotherapy for advanced breast cancer or not. The subgroup analyses showed a persistent PFS benefit regardless of the subgroup chosen. Pooled analysis shows PARP inhibitors likely result in a moderate improvement in tumour response rate compared to other treatment arms (66.9% vs 48.9%; RR 1.39, 95% CI 1.24 to 1.54; 5 studies; 1185 participants; moderate-certainty evidence). The most common adverse events reported across all five studies included neutropenia, anaemia and fatigue. Grade 3 or higher adverse events probably occur no less frequently in patients receiving PARP inhibitors (59.4% for PARP arm versus 64.5% for non-PARP arm, RR 0.98, 95% CI 0.91 to 1.04; 5 studies; 1443 participants; moderate-certainty evidence). Only two studies reported quality of life outcomes so this was not amenable to meta-analysis. However, both studies that did assess quality of life showed PARP inhibitors were superior compared to physician's choice of chemotherapy in terms of participant-reported outcomes.

AUTHORS' CONCLUSIONS

In people with locally advanced or metastatic HER2-negative, BRCA germline mutated breast cancer, PARP inhibitors offer an improvement in progression-free survival, and likely improve overall survival and tumour response rates. This systematic review provides evidence supporting the use of PARP inhibitors as part of the therapeutic strategy for breast cancer patients in this subgroup. The toxicity profile for PARP inhibitors is probably no worse than chemotherapy but more information is required regarding quality of life outcomes, highlighting the importance of collecting such data in future studies. Future studies should also be powered to detect clinically important differences in overall survival and could focus on the role of PARP inhibitors in other relevant breast cancer populations, including HER2-positive, BRCA-negative/homologous recombination repair-deficient and Programmed Death-Ligand 1 (PDL1) positive.

Hyperbaric oxygen and radiation therapy: a review

About 5% of cancer patients treated with radiotherapy will have severe late-onset toxicity. Hyperbaric oxygen therapy (HBOT) has been used as a treatment for radiation injuries for decades, with many publications presenting data from small series or individual cases. Moreover, we know that the hypoxic areas of tumours are more resistant to radiation. HBOT increases the oxygen tension in tissues and, theoretically, it should enhance the efficiency of radiotherapy. To better understand how HBOT works, we carried out this bibliographic review. We found Grade B and C evidence that at pressures exceeding 2 absolute atmospheres (ata), HBOT reduced late-onset radiation injuries to the head and neck, bone, prostate and bladder. It also appeared to prevent osteoradionecrosis after exodontia in irradiated areas. Finally, HBOT at 2 ata increased the effectiveness of radiation in head and neck tumours and achieved promising results in the local control of high-grade gliomas.

Anti-angiogenic therapy for high-grade glioma

BACKGROUND

This is an updated version of the original Cochrane Review published in September 2014. The most common primary brain tumours in adults are gliomas. Gliomas span a spectrum from low to high grade and are graded pathologically on a scale of one to four according to the World Health Organization (WHO) classification. High-grade glioma (HGG) carries a poor prognosis. Grade IV glioma is known as glioblastoma and carries a median survival in treated patients of about 15 months. Glioblastomas are rich in blood vessels (i.e. highly vascular) and also rich in a protein known as vascular endothelial growth factor (VEGF) that promotes new blood vessel formation (the process of angiogenesis). Anti-angiogenic agents inhibit the process of new blood vessel formation and promote regression of existing vessels. Several anti-angiogenic agents have been investigated in clinical trials, both in newly diagnosed and recurrent HGG, showing preliminary promising results. This review was undertaken to report on the benefits and harms associated with the use of anti-angiogenic agents in the treatment of HGGs.

OBJECTIVES

To evaluate the efficacy and toxicity of anti-angiogenic therapy in people with high-grade glioma (HGG). The intervention can be used in two broad groups: at first diagnosis as part of 'adjuvant' therapy, or in the setting of recurrent disease.

SEARCH METHODS

We conducted updated searches to identify published and unpublished randomised controlled trials (RCTs), including the Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 9), MEDLINE and Embase to October 2018. We handsearched proceedings of relevant oncology conferences up to 2018. We also searched trial registries for ongoing studies.

SELECTION CRITERIA

RCTs evaluating the use of anti-angiogenic therapy to treat HGG versus the same therapy without anti-angiogenic therapy.

DATA COLLECTION AND ANALYSIS

Review authors screened the search results and reviewed the abstracts of potentially relevant articles before retrieving the full text of eligible articles.

MAIN RESULTS

After a comprehensive literature search, we identified 11 eligible RCTs (3743 participants), of which 7 were included in the original review (2987 participants). There was significant design heterogeneity in the included studies, especially in the response assessment criteria used. All eligible studies were restricted to glioblastomas and there were no eligible studies evaluating other HGGs. Ten studies were available as fully published peer-reviewed manuscripts, and one study was available in abstract form. The overall risk of bias in included studies was low. This risk was based upon low rates of selection bias, detection bias, attrition bias and reporting bias. The 11 studies included in this review did not show an improvement in overall survival with the addition of anti-angiogenic therapy (pooled hazard ratio (HR) of 0.95, 95% confidence interval (CI) 0.88 to 1.02; P = 0.16; 11 studies, 3743 participants; high-certainty evidence). However, pooled analysis from 10 studies (3595 participants) showed improvement in progression-free survival with the addition of anti-angiogenic therapy (HR 0.73, 95% CI 0.68 to 0.79; P < 0.00001; high-certainty evidence).We carried out additional analyses of overall survival and progression-free survival according to treatment setting and for anti-angiogenic therapy combined with chemotherapy compared to chemotherapy alone. Pooled analysis of overall survival in either the adjuvant or recurrent setting did not show an improvement (HR 0.93, 95% CI 0.86 to 1.02; P = 0.12; 8 studies, 2833 participants; high-certainty evidence and HR 0.99, 95% CI 0.85 to 1.16; P = 0.90; 3 studies, 910 participants; moderate-certainty evidence, respectively). Pooled analysis of overall survival for anti-angiogenic therapy combined with chemotherapy compared to chemotherapy also did not clearly show an improvement (HR 0.92, 95% CI 0.85 to 1.00; P = 0.05; 11 studies, 3506 participants; low-certainty evidence). The progression-free survival in the subgroups all showed findings that demonstrated improvements in progression-free survival with the addition of anti-angiogenic therapy. Pooled analysis of progression-free survival in both the adjuvant and recurrent setting showed an improvement (HR 0.75, 95% CI 0.69 to 0.82; P < 0.00001; 8 studies, 2833 participants; high-certainty evidence and HR 0.64, 95% CI 0.54 to 0.76; P < 0.00001; 2 studies, 762 participants; moderate-certainty evidence, respectively). Pooled analysis of progression-free survival for anti-angiogenic therapy combined with chemotherapy compared to chemotherapy alone showed an improvement (HR 0.72, 95% CI 0.66 to 0.77; P < 0.00001; 10 studies, 3464 participants). Similar to trials of anti-angiogenic therapies in other solid tumours, adverse events related to this class of therapy included hypertension and proteinuria, poor wound healing, and the potential for thromboembolic events, although generally, the rate of grade 3 and 4 adverse events was low (< 14.1%) and in keeping with the literature. The impact of anti-angiogenic therapy on quality of life varied between studies.

AUTHORS' CONCLUSIONS

The use of anti-angiogenic therapy does not significantly improve overall survival in newly diagnosed people with glioblastoma. Thus, there is insufficient evidence to support the use of anti-angiogenic therapy for people with newly diagnosed glioblastoma at this time. Overall there is a lack of evidence of a survival advantage for anti-angiogenic therapy over chemotherapy in recurrent glioblastoma. When considering the combination anti-angiogenic therapy with chemotherapy compared with the same chemotherapy alone, there may possibly be a small improvement in overall survival. While there is strong evidence that bevacizumab (an anti-angiogenic drug) prolongs progression-free survival in newly diagnosed and recurrent glioblastoma, the impact of this on quality of life and net clinical benefit for patients remains unclear. Not addressed here is whether subsets of people with glioblastoma may benefit from anti-angiogenic therapies, nor their utility in other HGG histologies.

Palliative chemotherapy and targeted therapies for esophageal and gastroesophageal junction cancer

BACKGROUND

Almost half of people with esophageal or gastroesophageal junction cancer have metastatic disease at the time of diagnosis. Chemotherapy and targeted therapies are increasingly used with a palliative intent to control tumor growth, improve quality of life, and prolong survival. To date, and with the exception of ramucirumab, evidence for the efficacy of palliative treatments for esophageal and gastroesophageal cancer is lacking.

OBJECTIVES

To assess the effects of cytostatic or targeted therapy for treating esophageal or gastroesophageal junction cancer with palliative intent.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, the Web of Science, PubMed Publisher, Google Scholar, and trial registries up to 13 May 2015, and we handsearched the reference lists of studies. We did not restrict the search to publications in English. Additional searches were run in September 2017 prior to publication, and they are listed in the 'Studies awaiting assessment' section.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) on palliative chemotherapy and/or targeted therapy versus best supportive care or control in people with esophageal or gastroesophageal junction cancer.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data. We assessed the quality and risk of bias of eligible studies according to the Cochrane Handbook for Systematic Reviews of Interventions. We calculated pooled estimates of effect using an inverse variance random-effects model for meta-analysis.

MAIN RESULTS

We identified 41 RCTs with 11,853 participants for inclusion in the review as well as 49 ongoing studies. For the main comparison of adding a cytostatic and/or targeted agent to a control arm, we included 11 studies with 1347 participants. This analysis demonstrated an increase in overall survival in favor of the arm with an additional cytostatic or targeted therapeutic agent with a hazard ratio (HR) of 0.75 (95% confidence interval (CI) 0.68 to 0.84, high-quality evidence). The median increased survival time was one month. Five studies in 750 participants contributed data to the comparison of palliative therapy versus best supportive care. We found a benefit in overall survival in favor of the group receiving palliative chemotherapy and/or targeted therapy compared to best supportive care (HR 0.81, 95% CI 0.71 to 0.92, high-quality evidence). Subcomparisons including only people receiving second-line therapies, chemotherapies, targeted therapies, adenocarcinomas, and squamous cell carcinomas all showed a similar benefit. The only individual agent that more than one study found to improve both overall survival and progression-free survival was ramucirumab. Palliative chemotherapy and/or targeted therapy increased the frequency of grade 3 or higher treatment-related toxicity. However, treatment-related deaths did not occur more frequently. Quality of life often improved in the arm with an additional agent.

AUTHORS' CONCLUSIONS

People who receive more chemotherapeutic or targeted therapeutic agents have an increased overall survival compared to people who receive less. These agents, administered as both first-line or second-line treatments, also led to better overall survival than best supportive care. With the exception of ramucirumab, it remains unclear which other individual agents cause the survival benefit. Although treatment-associated toxicities of grade 3 or more occurred more frequently in arms with an additional chemotherapy or targeted therapy agent, there is no evidence that palliative chemotherapy and/or targeted therapy decrease quality of life. Based on this meta-analysis, palliative chemotherapy and/or targeted therapy can be considered standard care for esophageal and gastroesophageal junction carcinoma.

Chemotherapy for advanced gastric cancer

BACKGROUND

Gastric cancer is the fifth most common cancer worldwide. In "Western" countries, most people are either diagnosed at an advanced stage, or develop a relapse after surgery with curative intent. In people with advanced disease, significant benefits from targeted therapies are currently limited to HER-2 positive disease treated with trastuzumab, in combination with chemotherapy, in first-line. In second-line, ramucirumab, alone or in combination with paclitaxel, demonstrated significant survival benefits. Thus, systemic chemotherapy remains the mainstay of treatment for advanced gastric cancer. Uncertainty remains regarding the choice of the regimen.

OBJECTIVES

To assess the efficacy of chemotherapy versus best supportive care (BSC), combination versus single-agent chemotherapy and different chemotherapy combinations in advanced gastric cancer.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE and Embase up to June 2016, reference lists of studies, and contacted pharmaceutical companies and experts to identify randomised controlled trials (RCTs).

SELECTION CRITERIA

We considered only RCTs on systemic, intravenous or oral chemotherapy versus BSC, combination versus single-agent chemotherapy and different chemotherapy regimens in advanced gastric cancer.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified studies and extracted data. A third investigator was consulted in case of disagreements. We contacted study authors to obtain missing information.

MAIN RESULTS

We included 64 RCTs, of which 60 RCTs (11,698 participants) provided data for the meta-analysis of overall survival. We found chemotherapy extends overall survival (OS) by approximately 6.7 months more than BSC (hazard ratio (HR) 0.3, 95% confidence intervals (CI) 0.24 to 0.55, 184 participants, three studies, moderate-quality evidence). Combination chemotherapy extends OS slightly (by an additional month) versus single-agent chemotherapy (HR 0.84, 95% CI 0.79 to 0.89, 4447 participants, 23 studies, moderate-quality evidence), which is partly counterbalanced by increased toxicity. The benefit of epirubicin in three-drug combinations, in which cisplatin is replaced by oxaliplatin and 5-FU is replaced by capecitabine is unknown.Irinotecan extends OS slightly (by an additional 1.6 months) versus non-irinotecan-containing regimens (HR 0.87, 95% CI 0.80 to 0.95, 2135 participants, 10 studies, high-quality evidence).Docetaxel extends OS slightly (just over one month) compared to non-docetaxel-containing regimens (HR 0.86, 95% CI 0.78 to 0.95, 2001 participants, eight studies, high-quality evidence). However, due to subgroup analyses, we are uncertain whether docetaxel-containing combinations (docetaxel added to a single-agent or two-drug combination) extends OS due to moderate-quality evidence (HR 0.80, 95% CI 0.71 to 0.91, 1466 participants, four studies, moderate-quality evidence). When another chemotherapy was replaced by docetaxel, there is probably little or no difference in OS (HR 1.05; 0.87 to 1.27, 479 participants, three studies, moderate-quality evidence). We found there is probably little or no difference in OS when comparing capecitabine versus 5-FU-containing regimens (HR 0.94, 95% CI 0.79 to 1.11, 732 participants, five studies, moderate-quality evidence) .Oxaliplatin may extend (by less than one month) OS versus cisplatin-containing regimens (HR 0.81, 95% CI 0.67 to 0.98, 1105 participants, five studies, low-quality evidence). We are uncertain whether taxane-platinum combinations with (versus without) fluoropyrimidines extend OS due to very low-quality evidence (HR 0.86, 95% CI 0.71 to 1.06, 482 participants, three studies, very low-quality evidence). S-1 regimens improve OS slightly (by less than an additional month) versus 5-FU-containing regimens (HR 0.91, 95% CI 0.83 to 1.00, 1793 participants, four studies, high-quality evidence), however since S-1 is used in different doses and schedules between Asian and non-Asian population, the applicability of this finding to individual populations is uncertain.

AUTHORS' CONCLUSIONS

Chemotherapy improves survival (by an additional 6.7 months) in comparison to BSC, and combination chemotherapy improves survival (by an additional month) compared to single-agent 5-FU. Testing all patients for HER-2 status may help to identify patients with HER-2-positive tumours, for whom, in the absence of contraindications, trastuzumab in combination with capecitabine or 5-FU in combination with cisplatin has been shown to be beneficial. For HER-2 negative people, all different two-and three-drug combinations including irinotecan, docetaxel, oxaliplatin or oral 5-FU prodrugs are valid treatment options for advanced gastric cancer, and consideration of the side effects of each regimen is essential in the treatment decision. Irinotecan-containing combinations and docetaxel-containing combinations (in which docetaxel was added to a single-agent or two-drug (platinum/5-FUcombination) show significant survival benefits in the comparisons studied above. Furthermore, docetaxel-containing three-drug regimens have increased response rates, but the advantages of the docetaxel-containing three-drug combinations (DCF, FLO-T) are counterbalanced by increased toxicity. Additionally, oxaliplatin-containing regimens demonstrated a benefit in OS as compared to the same regimen containing cisplatin, and there is a modest survival improvement of S-1 compared to 5-FU-containing regimens.Whether the survival benefit for three-drug combinations including cisplatin, 5-FU, and epirubicin as compared to the same regimen without epirubicin is still valid when second-line therapy is routinely administered and when cisplatin is replaced by oxaliplatin and 5-FU by capecitabine is questionable. Furthermore, the magnitude of the observed survival benefits for the three-drug regimens is not large enough to be clinically meaningful as defined recently by the American Society for Clinical Oncology (Ellis 2014). In contrast to the comparisons in which a survival benefit was observed by adding a third drug to a two-drug regimen at the cost of increased toxicity, the comparison of regimens in which another chemotherapy was replaced by irinotecan was associated with a survival benefit (of borderline statistical significance), but without increased toxicity. For this reason irinotecan/5-FU-containing combinations are an attractive option for first-line treatment. Although they need to be interpreted with caution, subgroup analyses of one study suggest that elderly people have a greater benefit form oxaliplatin, as compared to cisplatin-based regimens, and that people with locally advanced disease or younger than 65 years might benefit more from a three-drug regimen including 5-FU, docetaxel, and oxaliplatin as compared to a two-drug combination of 5-FU and oxaliplatin, a hypothesis that needs further confirmation. For people with good performance status, the benefit of second-line chemotherapy has been established in several RCTs.

Hyperbaric Oxygen as Radiation Sensitizer for Locally Advanced Squamous Cell Carcinoma of the Oropharynx: A Phase 1 Dose-Escalation Study

PURPOSE

To explore, in a dose-escalation study, the feasibility of hyperbaric oxygen (HBO) treatments immediately before intensity modulated radiation therapy in conjunction with cisplatinum chemotherapy for squamous cell carcinoma of the head and neck (SCCHN).

METHODS AND MATERIALS

Eligible patients presented with SCCHN (stage III-IV [M0]), life expectancy >6 months, and Karnofsky performance status ≥70. Enrollees received intensity modulated radiation therapy, 70 Gy in 35 fractions over 7 weeks with weekly cisplatinum. Patients received HBO-100% oxygen, 2.4 atmospheres absolute (ATA) for 30 minutes-twice per week initially. Subsequent patients were escalated to 3 and then 5 times per week. Intensity modulated radiation therapy began within 15 minutes after HBO. Patients were followed for 2 years after RT with quality-of-life questionnaires (Performance Status Scale-Head and Neck Cancer and the Functional Assessment of Cancer Therapy-Head and Neck Cancer) and for 5+ years for local recurrence, distant metastases, disease-specific survival, and overall survival.

RESULTS

Twelve subjects enrolled from 3 centers. Two withdrew during radiation therapy and 1 within 14 weeks after radiation therapy. The remaining 9 had primary oropharyngeal disease and were stage IVA (7) or IVB (2). No dose-limiting toxicities were observed with daily HBO. Two patients (22%) required pressure equalization tubes. The average time between HBO and radiation therapy was 8.5 minutes, with 2 of 231 administrations delivered beyond 15 minutes (0.5%). Per-protocol analysis showed a clinical complete response in 7 and a pathologic complete response without tumor in salvage neck dissections in 2. With minimum follow-up of 61 months, per-protocol 5-year overall survival was 100%, local recurrence 0%, and distant metastases 11%. Patient-reported outcomes for quality of life (Functional Assessment of Cancer Therapy-Head and Neck Cancer) were comparable to published results for chemoradiotherapy without HBO.

CONCLUSIONS

While acknowledging the study's small size and early attrition of 3 patients, our in-depth review of the acquired data indicates the feasibility of combining HBO with chemoradiation.

Parents' and Adolescents' Preferences for Intensified or Reduced Treatment in Randomized Lymphoblastic Leukemia Trials

BACKGROUND

When offered participation in clinical trials, families of children with cancer face a delicate balance between cure and toxicity. Since parents and children may perceive this balance differently, this paper explores whether adolescent patients have different enrollment patterns compared to younger children in trials with different toxicity profiles.

PROCEDURE

Age-dependent participation rates in three consecutive, randomized childhood leukemia trials conducted by the Nordic Society of Paediatric Haematology and Oncology were evaluated. The ALL2000 dexamethasone/vincristine (Dx/VCR) trial tested treatment intensifications to improve cure, and the back-to-back ALL2008 6-mercaptopurine (6MP) and ALL2008 PEG-asparaginase (ASP) trials tested treatment intensifications (6MP) and toxicity reduction without compromising survival (ASP). Patient randomization and toxicity data were prospectively registered by the treating physicians.

RESULTS

Parents of young children favored treatment intensifications (Dx/VCR: 12% refusal; 6MP: 14%; ASP: 21%), whereas parents of adolescents favored treatment reductions (Dx/VCR: 52% refusal; 6MP: 30%; ASP: 8%). Adolescents were more likely to refuse intensification trials than young children (adjusted ORs 6.3; P < 0.01 [Dx/VCR] and 2.1; P = 0.04 [6MP]). Adolescents were less likely to refuse the ASP trial, with varying effect size depending on the length of the preceding consolidation treatment (adjusted OR for median consolidation length 0.15; P = 0.01). Younger children participated more frequently in only 6MP than in only ASP (14% vs. 5%), and adolescents vice versa (2% vs. 17%; P = 0.001).

CONCLUSIONS

Parents' and adolescents' divergent inclinations toward intensified or reduced therapy emphasize the necessity of actively involving adolescents in the informed consent process, which should also address motives for trial participation.

Control treatments in biologics trials of rheumatoid arthritis were often not deemed acceptable in the context of care

OBJECTIVES

Control treatments in randomized controlled trials (RCTs) should not deliberately disadvantage patients. The objectives of the study were to compare (1) willingness to include vs. (2) willingness to prescribe control treatment among physicians randomized to assess, respectively, either (1) enrollment in a trial or (2) appropriateness of control treatment in a care context for the same fictional patient.

STUDY DESIGN AND SETTING

Physicians were authors of articles about rheumatoid arthritis (RA), involved in RA patient care, and used to enrolling patients in trials. The outcomes were willingness to give control treatment: trial enrollment or control-treatment appropriateness in care context. We derived three case vignettes of fictional standard eligible patients for each of 30 RCTs assessing biologics in RA. Physicians were randomly allocated to the "trial" or "care" arm. For each of the 90 fictional patients, physicians assigned to the trial arm were asked if they would enroll the patient in the RCT the patient was derived from. For the same 90 fictional patients, physicians assigned to the care arm were asked if the control treatment of the RCT was appropriate in a context of usual care.

RESULTS

Of the 1,779 physicians invited to participate, 151 were randomized. Half of the fictional patients {41/90; 45% [95% confidence interval (CI): 37%, 53%]} would be enrolled in the RCT although the control-arm treatment of the RCT was not considered appropriate for them in the context of care. This rate differed by type of comparator [55% for non-head-to-head RCTs vs. 6% for head-to-head RCTs; adjusted odds ratio (aOR), 23.9 (95% CI: 5.5, 92.7)] and duration of trial control treatment [56% for ≤24 weeks and 15% for >24 weeks; aOR, 10.7 (95% CI: 2.8, 63.9)] but not patient RA activity [aOR, 2.5 (95% CI: 1.0, 6.6)]. The limitation of this study was that physicians gave their opinion on fictional patients with only RA.

CONCLUSIONS

Control treatments in RCTs of biologics in RA are often deemed not acceptable in the context of usual care, especially those for non-head-to-head RCTs. These findings raise ethical concerns and challenge the choice of the comparator in RCTs.

Percutaneous ethanol injection or percutaneous acetic acid injection for early hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the fifth most common global cancer. When HCC is diagnosed early, interventions such as percutaneous ethanol injection (PEI), percutaneous acetic acid injection (PAI), or radiofrequency (thermal) ablation (RF(T)A) may have curative potential and represent less invasive alternatives to surgery.

OBJECTIVES

To evaluate the beneficial and harmful effects of PEI or PAI in adults with early HCC defined according to the Milan criteria, that is, one cancer nodule up to 5 cm in diameter or up to three cancer nodules up to 3 cm in diameter compared with no intervention, sham intervention, each other, other percutaneous interventions, or surgery.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register (July 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (2014, Issue 6), MEDLINE (1946 to July 2014), EMBASE (1976 to July 2014), and Science Citation Index Expanded (1900 to July 2014). We handsearched meeting abstracts of six oncological and hepatological societies and references of articles to July 2014. We contacted researchers in the field.

SELECTION CRITERIA

We considered randomised clinical trials comparing PEI or PAI versus no intervention, sham intervention, each other, other percutaneous interventions, or surgery for the treatment of early HCC regardless of blinding, publication status, or language. We excluded studies comparing RFA or combination of different interventions as such interventions have been or will be addressed in other Cochrane Hepato-Biliary Group systematic reviews.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, and extracted and analysed data. We calculated the hazard ratios (HR) for median overall survival and recurrence-free survival using the Cox regression model with Parmar's method. We reported type and number of adverse events descriptively. We assessed risk of bias by The Cochrane Collaboration domains to reduce systematic errors and risk of play of chance by trial sequential analysis to reduce random errors. We assessed the methodological quality with GRADE.

MAIN RESULTS

We identified three randomised trials with 261 participants for inclusion. The risk of bias was low in one and high in two trials.Two of the randomised trials compared PEI versus PAI; we included 185 participants in the analysis. The overall survival (HR 1.47; 95% confidence interval (CI) 0.68 to 3.19) and recurrence-free survival (HR 1.42; 95% CI 0.68 to 2.94) were not statistically significantly different between the intervention groups of the two trials. Trial sequential analysis for the comparison PEI versus PAI including two trials revealed that the number of participants that were included in the trials were insufficient in order to judge a relative risk reduction of 20%. Data on the duration of hospital stay were available from one trial for the comparison PEI versus PAI showing a significantly shorter hospital stay for the participants treated with PEI (mean 1.7 days; range 2 to 3 days) versus PAI (mean 2.2 days; range 2 to 5 days). Quality of life was not reported. There were only mild adverse events in participants treated with either PEI or PAI such as transient fever, flushing, and local pain.One randomised trial compared PEI versus surgery; we included 76 participants in the analyses. There was no significant difference in the overall survival (HR 1.57; 95% CI 0.53 to 4.61) and recurrence-free survival (HR 1.35; 95% CI 0.69 to 2.63). No serious adverse events were reported in the PEI group while three postoperative deaths occurred in the surgery group.In addition to the three randomised trials, we identified one quasi-randomised study comparing PEI versus PAI. Due to methodological flaws of the study, we extracted only the data on adverse events and presented them in a narrative way.We found no randomised trials that compared PEI or PAI versus no intervention, best supportive care, sham intervention, or other percutaneous local ablative therapies excluding RFTA. We found also no randomised clinical trials that compared PAI versus other interventional treatments or surgery. We identified two ongoing randomised clinical trials. One of these two trials compares PEI versus surgery and the other PEI versus transarterial chemoembolization. To date, it is unclear whether the trials will be eligible for inclusion in this meta-analysis as the data are not yet available. This review will not be updated until new randomised clinical trials are published and can be used for analysis.

AUTHORS' CONCLUSIONS

PEI versus PAI did not differ significantly regarding benefits and harms in people with early HCC, but the two included trials had only a limited number of participants and one trial was judged a high risk of bias. Thus, the current evidence precludes us from making any firm conclusions.There was also insufficient evidence to determine whether PEI versus surgery (segmental liver resection) was more effective, because conclusions were based on a single randomised trial. While some data from this single trial suggested that PEI was safer, the high risk of bias and the lack of any confirmatory evidence make a reliable assessment impossible.We found no trials assessing PEI or PAI versus no intervention, best supportive care, or sham intervention.There is a need for more randomised clinical trials assessing interventions for people with early stage HCC. Such trials should be conducted with low risks of systematic errors and random errors.

Percutaneous ethanol injection or percutaneous acetic acid injection for early hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the fifth most common global cancer. When HCC is diagnosed early, interventions such as percutaneous ethanol injection (PEI), percutaneous acetic acid injection (PAI), or radiofrequency (thermal) ablation (RF(T)A) may have curative potential and represent less invasive alternatives to surgery.

OBJECTIVES

To evaluate the beneficial and harmful effects of PEI or PAI in adults with early HCC defined according to the Milan criteria, that is, one cancer nodule up to 5 cm in diameter or up to three cancer nodules up to 3 cm in diameter compared with no intervention, sham intervention, each other, other percutaneous interventions, or surgery.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register (July 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (2014, Issue 6), MEDLINE (1946 to July 2014), EMBASE (1976 to July 2014), and Science Citation Index Expanded (1900 to July 2014). We handsearched meeting abstracts of six oncological and hepatological societies and references of articles to July 2014. We contacted researchers in the field.

SELECTION CRITERIA

We considered randomised clinical trials comparing PEI or PAI versus no intervention, sham intervention, each other, other percutaneous interventions, or surgery for the treatment of early HCC regardless of blinding, publication status, or language. We excluded studies comparing RFA or combination of different interventions as such interventions have been or will be addressed in other Cochrane Hepato-Biliary Group systematic reviews.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, and extracted and analysed data. We calculated the hazard ratios (HR) for median overall survival and recurrence-free survival using the Cox regression model with Parmar's method. We reported type and number of adverse events descriptively. We assessed risk of bias by The Cochrane Collaboration domains to reduce systematic errors and risk of play of chance by trial sequential analysis to reduce random errors. We assessed the methodological quality with GRADE.

MAIN RESULTS

We identified three randomised trials with 261 participants for inclusion. The risk of bias was low in one and high in two trials.Two of the randomised trials compared PEI versus PAI; we included 185 participants in the analysis. The overall survival (HR 1.47; 95% confidence interval (CI) 0.68 to 3.19) and recurrence-free survival (HR 1.42; 95% CI 0.68 to 2.94) were not statistically significantly different between the intervention groups of the two trials. Trial sequential analysis for the comparison PEI versus PAI including two trials revealed that the number of participants that were included in the trials were insufficient in order to judge a relative risk reduction of 20%. Data on the duration of hospital stay were available from one trial for the comparison PEI versus PAI showing a significantly shorter hospital stay for the participants treated with PEI (mean 1.7 days; range 2 to 3 days) versus PAI (mean 2.2 days; range 2 to 5 days). Quality of life was not reported. There were only mild adverse events in participants treated with either PEI or PAI such as transient fever, flushing, and local pain.One randomised trial compared PEI versus surgery; we included 76 participants in the analyses. There was no significant difference in the overall survival (HR 1.57; 95% CI 0.53 to 4.61) and recurrence-free survival (HR 1.35; 95% CI 0.69 to 2.63). No serious adverse events were reported in the PEI group while three postoperative deaths occurred in the surgery group.In addition to the three randomised trials, we identified one quasi-randomised study comparing PEI versus PAI. Due to methodological flaws of the study, we extracted only the data on adverse events and presented them in a narrative way.We found no randomised trials that compared PEI or PAI versus no intervention, best supportive care, sham intervention, or other percutaneous local ablative therapies excluding RFTA. We found also no randomised clinical trials that compared PAI versus other interventional treatments or surgery. We identified two ongoing randomised clinical trials. One of these two trials compares PEI versus surgery and the other PEI versus transarterial chemoembolization. To date, it is unclear whether the trials will be eligible for inclusion in this meta-analysis as the data are not yet available. This review will not be updated until new randomised clinical trials are published and can be used for analysis.

AUTHORS' CONCLUSIONS

PEI versus PAI did not differ significantly regarding benefits and harms in people with early HCC, but the two included trials had only a limited number of participants and one trial was judged a high risk of bias. Thus, the current evidence precludes us from making any firm conclusions.There was also insufficient evidence to determine whether PEI versus surgery (segmental liver resection) was more effective, because conclusions were based on a single randomised trial. While some data from this single trial suggested that PEI was safer, the high risk of bias and the lack of any confirmatory evidence make a reliable assessment impossible.We found no trials assessing PEI or PAI versus no intervention, best supportive care, or sham intervention.There is a need for more randomised clinical trials assessing interventions for people with early stage HCC. Such trials should be conducted with low risks of systematic errors and random errors.

Antiangiogenic therapy for high-grade glioma

BACKGROUND

The most common primary brain tumours in adults are gliomas. Gliomas span a spectrum from low to high-grade and are graded pathologically on a scale of one to four according to the World Health Organization (WHO) classification. High-grade glioma (HGG) carries a poor prognosis. Grade IV glioma is known as glioblastoma (GBM) and carries a median survival in treated patients of about 15 months. GBMs are rich in blood vessels (i.e. highly vascular) and in a protein known as vascular endothelial growth factor (VEGF), which promotes new blood vessel formation (the process of angiogenesis). Antiangiogenic agents inhibit the process of new blood vessel formation and promote regression of existing vessels. Several antiangiogenic agents have been investigated in clinical trials in newly diagnosed and recurrent HGG, showing promising preliminary results. This review was undertaken to report on the benefits and harms associated with the use of antiangiogenic agents in the treatment of HGGs.

OBJECTIVES

To evaluate the efficacy and toxicity of antiangiogenic therapy in patients with high-grade glioma. This intervention can be used in two broad groups of patients: those with first diagnosis as part of 'adjuvant' therapy, and those with recurrent or progressive disease. Comparisons will include the following.• Treatment with antiangiogenic therapy versus placebo.• Treatment (such as chemotherapy or chemoradiotherapy) with antiangiogenic therapy added versus the same treatment without the addition of antiangiogenic therapy.

SEARCH METHODS

Searches were conducted to identify published and unpublished Randomised Controlled Trials (RCTs) starting in 2000; the following databases were searched: the Cochrane Central Register of Controlled Trials (CENTRAL), Issue 3, 2014; MEDLINE to April 2014 and EMBASE to April 2014. Proceedings of relevant oncology conferences since 2000 were handsearched.

SELECTION CRITERIA

RCTs evaluating the use of antiangiogenic therapy versus control treatment without antiangiogenic therapy in the treatment of HGG.

DATA COLLECTION AND ANALYSIS

Review authors screened the search results and reviewed the abstracts of potentially relevant articles before retrieving the full text of eligible articles.

MAIN RESULTS

After a comprehensive literature search, seven eligible RCTs were identified (total of 2987 participants). Significant design heterogeneity was noted in the included studies, especially in the response assessment criteria used. All eligible studies were restricted to GBMs, and no eligible studies evaluated other HGGs. Four studies were available only in abstract form. We have reserved an overall assessment of the quality of the evidence until the final study publications are received. The three studies that have been published in full were judged to have low risk of bias. The seven trials of 2987 participants included in this systematic review did not show improvement in OS with the addition of antiangiogenic therapy (pooled hazard ratio (HR) 0.94, 95% confidence interval (CI) 0.86 to 1.02; P value 0.16). However, pooled analysis of PFS from six studies (2847 participants) showed improvement in PFS with the addition of antiangiogenic therapy (HR 0.74, 95% CI 0.68 to 0.81; P value < 0.00001). Bevacizumab was the antiangiogenic therapy more likely to yield favourable results. Pooled HR for PFS for bevacizumab studies (three studies with 1712 participants) was significant at 0.66 (95% CI 0.59 to 0.74; P value < 0.00001), and this was reflected in the lower hazard ratio reported in the pooled analysis of bevacizumab studies compared with the overall analysis. Nevertheless, this finding was not significant for OS (HR 0.92, 95% CI 0.83 to 1.02; P value 0.12). Similar to trials of antiangiogenic therapies in other solid tumours, adverse events related to this class of therapy included hypertension and proteinuria, poor wound healing and the potential for thromboembolic events, although generally, the occurrence of grade 3 events of this kind was low (< 14.1%), consistent with reported findings of studies of bevacizumab in other tumours.

AUTHORS' CONCLUSIONS

In patients with newly diagnosed GBM, the use of antiangiogenic therapy does not improve survival, despite evidence of improved progression-free survival. Thus at this time, evidence is insufficient to support the use of antiangiogenic therapy in patients with newly diagnosed GBM on the basis of effects on survival.Bevacizumab may confer a progression-free survival benefit in GBM; however evidence in favour of using other antiangiogenic therapies in recurrent GBM is insufficient.Although bevacizumab appears to prolong progression-free survival in newly diagnosed and recurrent GBM, the impact of this on quality of life remains unclear.Adequately powered, randomised, placebo-controlled studies of bevacizumab in recurrent GBM (or HGG) are needed.Not addressed here is whether subsets of patients with newly diagnosed GBM may benefit from antiangiogenic therapies and whether these therapies are useful in other high-grade glioma histologies.

Radiofrequency (thermal) ablation versus no intervention or other interventions for hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma is the fifth most common cancer worldwide. Percutaneous interventional therapies, such as radiofrequency (thermal) ablation (RFA), have been developed for early hepatocellular carcinoma. RFA competes with other interventional techniques such as percutaneous ethanol injection, surgical resection, and liver transplantation. The potential benefits and harms of RFA compared with placebo, no intervention, chemotherapy, hepatic resection, liver transplantation, or other interventions are unclear.

OBJECTIVES

To assess the beneficial and harmful effects of RFA versus placebo, no intervention, or any other therapeutic approach in patients with hepatocellular carcinoma.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and ISI Web of Science to September 2012. We handsearched meeting abstracts from ASCO, ESMO, AASLD, EASL, APASL, and references of articles. We also contacted researchers in the field (last search September 2012).

SELECTION CRITERIA

We considered for inclusion randomised clinical trials investigating the effects of RFA versus placebo, no intervention, or any other therapeutic approach on hepatocellular carcinoma patients regardless of blinding, language, and publication status.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed the selection of trials, assessment of risk of bias, and data extraction. We contacted principal investigators for missing information. We analysed hazard ratios (HR) as relevant effect measures for overall survival, two-year survival, event-free survival, and local recurrences with 95% confidence intervals (CI). In addition, we analysed dichotomous survival outcomes using risk ratios (RR). We used trial sequential analysis to control the risk of random errors ('play of chance').

MAIN RESULTS

We identified no trials comparing RFA versus placebo, no intervention, or liver transplantation. We identified and included 11 randomised clinical trials with 1819 participants that included four comparisons: RFA versus hepatic resection (three trials, 578 participants); RFA versus percutaneous ethanol injection (six trials, 1088 participants) including one three-armed trial that also investigated RFA versus acetic acid injection; RFA versus microwave ablation (one trial, 72 participants); and RFA versus laser ablation (one trial, 81 participants). Ten of the eleven included trials reported on the primary outcome of this review, overall survival. Rates of major complications or procedure-related deaths were reported in 10 trials. The overall risk of bias was considered low in five trials and high in six trials. For a subgroup analysis, we included only low risk of bias trials. Regarding the comparison RFA versus hepatic resection, there was moderate-quality evidence from two low risk of bias trials that hepatic resection seems more effective than RFA regarding overall survival (HR 0.56; 95% CI 0.40 to 0.78) and two-year survival (HR 0.38; 95% CI 0.17 to 0.84). However, if we included a third trial with high risk of bias, the difference became insignificant (overall survival: HR 0.71; 95% CI 0.44 to 1.15). With regards to the outcomes event-free survival and local progression, hepatic resection also yielded better results than RFA. However, the number of complications was higher in surgically treated participants (odds ratio (OR) 8.24; 95% CI 2.12 to 31.95). RFA seemed superior to percutaneous ethanol or acetic acid injection regarding overall survival (HR 1.64; 95% CI 1.31 to 2.07). The RR for mortality was also in favour of RFA, but did not reach statistical significance (150/490 (30.6%) people in the percutaneous ethanol or acetic acid group versus 119/496 (24.0%) people in the RFA group; RR 1.76; 95% CI 0.97 to 3.22). The proportion of adverse events did not differ significantly between RFA and percutaneous ethanol or acetic acid injection (HR 0.70; 95% CI 0.33 to 1.48). Trial sequential analyses revealed that the number of participants in the included trials was insufficient and that more trials are needed to assess the effects of RFA versus other interventions.

AUTHORS' CONCLUSIONS

The effects of RFA versus no intervention, chemotherapeutic treatment, or liver transplantation are unknown. We found moderate-quality evidence that hepatic resection is superior to RFA regarding survival. However, RFA might be associated with fewer complications and a shorter hospital stay than hepatic resection. We found moderate-quality evidence showing that RFA seems superior to percutaneous ethanol injection regarding survival. There were too sparse data to recommend or refute ablation achieved by techniques other than RFA. More randomised clinical trials with low risk of bias and low risks of random errors assessing the effect of RFA are needed.

Treatment success in cancer: industry compared to publicly sponsored randomized controlled trials

OBJECTIVE

To assess if commercially sponsored trials are associated with higher success rates than publicly-sponsored trials.

STUDY DESIGN AND SETTINGS

We undertook a systematic review of all consecutive, published and unpublished phase III cancer randomized controlled trials (RCTs) conducted by GlaxoSmithKline (GSK) and the NCIC Clinical Trials Group (CTG). We included all phase III cancer RCTs assessing treatment superiority from 1980 to 2010. Three metrics were assessed to determine treatment successes: (1) the proportion of statistically significant trials favouring the experimental treatment, (2) the proportion of the trials in which new treatments were considered superior according to the investigators, and (3) quantitative synthesis of data for primary outcomes as defined in each trial.

RESULTS

GSK conducted 40 cancer RCTs accruing 19,889 patients and CTG conducted 77 trials enrolling 33,260 patients. 42% (99%CI 24 to 60) of the results were statistically significant favouring experimental treatments in GSK compared to 25% (99%CI 13 to 37) in the CTG cohort (RR = 1.68; p = 0.04). Investigators concluded that new treatments were superior to standard treatments in 80% of GSK compared to 44% of CTG trials (RR = 1.81; p<0.001). Meta-analysis of the primary outcome indicated larger effects in GSK trials (odds ratio = 0.61 [99%CI 0.47-0.78] compared to 0.86 [0.74-1.00]; p = 0.003). However, testing for the effect of treatment over time indicated that treatment success has become comparable in the last decade.

CONCLUSIONS

While overall industry sponsorship is associated with higher success rates than publicly-sponsored trials, the difference seems to have disappeared over time.

New treatments compared to established treatments in randomized trials

BACKGROUND

The proportion of proposed new treatments that are 'successful' is of ethical, scientific, and public importance. We investigated how often new, experimental treatments evaluated in randomized controlled trials (RCTs) are superior to established treatments.

OBJECTIVES

Our main question was: "On average how often are new treatments more effective, equally effective or less effective than established treatments?" Additionally, we wanted to explain the observed results, i.e. whether the observed distribution of outcomes is consistent with the 'uncertainty requirement' for enrollment in RCTs. We also investigated the effect of choice of comparator (active versus no treatment/placebo) on the observed results.

SEARCH METHODS

We searched the Cochrane Methodology Register (CMR) 2010, Issue 1 in The Cochrane Library (searched 31 March 2010); MEDLINE Ovid 1950 to March Week 2 2010 (searched 24 March 2010); and EMBASE Ovid 1980 to 2010 Week 11 (searched 24 March 2010).

SELECTION CRITERIA

Cohorts of studies were eligible for the analysis if they met all of the following criteria: (i) consecutive series of RCTs, (ii) registered at or before study onset, and (iii) compared new against established treatments in humans.

DATA COLLECTION AND ANALYSIS

RCTs from four cohorts of RCTs met all inclusion criteria and provided data from 743 RCTs involving 297,744 patients. All four cohorts consisted of publicly funded trials. Two cohorts involved evaluations of new treatments in cancer, one in neurological disorders, and one for mixed types of diseases. We employed kernel density estimation, meta-analysis and meta-regression to assess the probability of new treatments being superior to established treatments in their effect on primary outcomes and overall survival.

MAIN RESULTS

The distribution of effects seen was generally symmetrical in the size of difference between new versus established treatments. Meta-analytic pooling indicated that, on average, new treatments were slightly more favorable both in terms of their effect on reducing the primary outcomes (hazard ratio (HR)/odds ratio (OR) 0.91, 99% confidence interval (CI) 0.88 to 0.95) and improving overall survival (HR 0.95, 99% CI 0.92 to 0.98). No heterogeneity was observed in the analysis based on primary outcomes or overall survival (I(2) = 0%). Kernel density analysis was consistent with the meta-analysis, but showed a fairly symmetrical distribution of new versus established treatments indicating unpredictability in the results. This was consistent with the interpretation that new treatments are only slightly superior to established treatments when tested in RCTs. Additionally, meta-regression demonstrated that results have remained stable over time and that the success rate of new treatments has not changed over the last half century of clinical trials. The results were not significantly affected by the choice of comparator (active versus placebo/no therapy).

AUTHORS' CONCLUSIONS

Society can expect that slightly more than half of new experimental treatments will prove to be better than established treatments when tested in RCTs, but few will be substantially better. This is an important finding for patients (as they contemplate participation in RCTs), researchers (as they plan design of the new trials), and funders (as they assess the 'return on investment'). Although we provide the current best evidence on the question of expected 'success rate' of new versus established treatments consistent with a priori theoretical predictions reflective of 'uncertainty or equipoise hypothesis', it should be noted that our sample represents less than 1% of all available randomized trials; therefore, one should exercise the appropriate caution in interpretation of our findings. In addition, our conclusion applies to publicly funded trials only, as we did not include studies funded by commercial sponsors in our analysis.

Treatment success in pragmatic randomised controlled trials: a review of trials funded by the UK Health Technology Assessment programme

BACKGROUND

Previous research reviewed treatment success and whether the collective uncertainty principle is met in RCTs in the US National Cancer Institute portfolio. This paper classifies clinical trials funded by the UK HTA programme by results using the method applied to the US Cancer Institute trials, and compares the two portfolios.

METHODS

Data on all completed randomised controlled trials funded by the HTA programme 1993-2008 were extracted. Each trial's primary results was classified into six categories; 1) statistically significant in favour of the new treatment, 2) statistically significant in favour of the control treatment 3) true negative, 4) truly inconclusive, 5) inconclusive in favour of new treatment or 6) inconclusive in favour of control treatment. Trials were classified by comparing the 95% confidence interval for the difference in primary outcome to the difference specified in the sample size calculation. The results were compared with Djulbegovic's analysis of NCI trials.

RESULTS

Data from 51 superiority trials were included, involving over 48,000 participants and a range of diseases and interventions. 85 primary comparisons were available because some trials had more than two randomised arms or had several primary outcomes. The new treatment had superior results (whether significant or not) in 61% of the comparisons (52/85 95% CI 49.9% to 71.6%). The results were conclusive in 46% of the comparisons (19% statistically significant in favour of the new treatment, 5% statistically significant in favour of the control and 22% true negative). The results were classified as truly inconclusive (i.e. failed to answer the question asked) for 24% of comparisons (20/85). HTA trials included fewer truly inconclusive and statistically significant results and more results rated as true negative than NCI trials.

CONCLUSIONS

The pattern of results in HTA trials is similar to that of the National Cancer Institute portfolio. Differences that existed were plausible given the differences in the types of trials -HTA trials are more pragmatic. The results indicate HTA trials are compatible with equipoise. This classification usefully summarises the results from clinical trials and enables comparisons of different portfolios of trials.

Chemotherapy for advanced gastric cancer

BACKGROUND

Gastric cancer currently ranks second in global cancer mortality. Most patients are either diagnosed at an advanced stage, or develop a relapse after surgery with curative intent. Apart from supportive care and palliative radiation to localized (e.g. bone) metastasis, systemic chemotherapy is the only treatment option available in this situation.

OBJECTIVES

To assess the efficacy of chemotherapy versus best supportive care, combination versus single agent chemotherapy and different combination chemotherapy regimens in advanced gastric cancer.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE up to March 2009, reference lists of studies, and contacted pharmaceutical companies and national and international experts.

SELECTION CRITERIA

Randomised controlled trials on systemic intravenous chemotherapy versus best supportive care, combination versus single agent chemotherapy and different combination chemotherapies in advanced gastric cancer.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data. A third investigator was consulted in case of disagreements. We contacted study authors to obtain missing information.

MAIN RESULTS

Thirty five trials, with a total of 5726 patients, have been included in the meta-analysis of overall survival. The comparison of chemotherapy versus best supportive care consistently demonstrated a significant benefit in overall survival in favour of the group receiving chemotherapy (hazard ratios (HR) 0.37; 95% confidence intervals (CI) 0.24 to 0.55, 184 participants). The comparison of combination versus single-agent chemotherapy provides evidence for a survival benefit in favour of combination chemotherapy (HR 0.82; 95% CI 0.74 to 0.90, 1914 participants). The price of this benefit is increased toxicity as a result of combination chemotherapy. When comparing 5-FU/cisplatin-containing combination therapy regimens with versus without anthracyclines (HR 0.77; 95% CI 0.62 to 0.95, 501 participants) and 5-FU/anthracycline-containing combinations with versus without cisplatin (HR 0.82; 95% CI 0.73 to 0.92, 1147 participants) there was a significant survival benefit for regimens including 5-FU, anthracyclines and cisplatin. Both the comparison of irinotecan versus non-irinotecan (HR 0.86; 95% CI 0.73 to 1.02, 639 participants) and docetaxel versus non-docetaxel containing regimens (HR 0.93; 95% CI 0.75 to 1.15, 805 participants) show non-significant overall survival benefits in favour of the irinotecan and docetaxel-containing regimens.

AUTHORS' CONCLUSIONS

Chemotherapy significantly improves survival in comparison to best supportive care. In addition, combination chemotherapy improves survival compared to single-agent 5-FU. All patients should be tested for their HER-2 status and trastuzumab should be added to a standard fluoropyrimidine/cisplatin regimen in patients with HER-2 positive tumours. Two and three-drug regimens including 5-FU, cisplatin, with or without an anthracycline, as well as irinotecan or docetaxel-containing regimens are reasonable treatment options for HER-2 negative patients.

Chemotherapy for advanced gastric cancer

BACKGROUND

Gastric cancer currently ranks second in global cancer mortality. Most patients are either diagnosed at an advanced stage, or develop a relapse after surgery with curative intent. Apart from supportive care and palliative radiation to localized (e.g. bone) metastasis, systemic chemotherapy is the only treatment option available in this situation.

OBJECTIVES

To assess the efficacy of chemotherapy versus best supportive care, combination versus single agent chemotherapy and different combination chemotherapy regimens in advanced gastric cancer.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE up to March 2009, reference lists of studies, and contacted pharmaceutical companies and national and international experts.

SELECTION CRITERIA

Randomised controlled trials on systemic intravenous chemotherapy versus best supportive care, combination versus single agent chemotherapy and different combination chemotherapies in advanced gastric cancer.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data. A third investigator was consulted in case of disagreements. We contacted study authors to obtain missing information.

MAIN RESULTS

Thirty five trials, with a total of 5726 patients, have been included in the meta-analysis of overall survival. The comparison of chemotherapy versus best supportive care consistently demonstrated a significant benefit in overall survival in favour of the group receiving chemotherapy (hazard ratios (HR) 0.37; 95% confidence intervals (CI) 0.24 to 0.55, 184 participants). The comparison of combination versus single-agent chemotherapy provides evidence for a survival benefit in favour of combination chemotherapy (HR 0.82; 95% CI 0.74 to 0.90, 1914 participants). The price of this benefit is increased toxicity as a result of combination chemotherapy. When comparing 5-FU/cisplatin-containing combination therapy regimens with versus without anthracyclines (HR 0.77; 95% CI 0.62 to 0.95, 501 participants) and 5-FU/anthracycline-containing combinations with versus without cisplatin (HR 0.82; 95% CI 0.73 to 0.92, 1147 participants) there was a significant survival benefit for regimens including 5-FU, anthracyclines and cisplatin. Both the comparison of irinotecan versus non-irinotecan (HR 0.86; 95% CI 0.73 to 1.02, 639 participants) and docetaxel versus non-docetaxel containing regimens (HR 0.93; 95% CI 0.75 to 1.15, 805 participants) show non-significant overall survival benefits in favour of the irinotecan and docetaxel-containing regimens.

AUTHORS' CONCLUSIONS

Chemotherapy significantly improves survival in comparison to best supportive care. In addition, combination chemotherapy improves survival compared to single-agent 5-FU. All patients should be tested for their HER-2 status and trastuzumab should be added to a standard fluoropyrimidine/cisplatin regimen in patients with HER-2 positive tumours. Two and three-drug regimens including 5-FU, cisplatin, with or without an anthracycline, as well as irinotecan or docetaxel-containing regimens are reasonable treatment options for HER-2 negative patients.

Percutaneous ethanol injection or percutaneous acetic acid injection for early hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the fifth most common global cancer. When HCC is detected early, interventions such as percutaneous ethanol injection (PEI), percutaneous acetic acid injection (PAI), and radiofrequency thermal ablation (RFTA) have curative potential and represent low invasive alternatives to surgery. The role of PEI or PAI has not been addressed in a systematic review.

OBJECTIVES

To evaluate the beneficial and harmful effects of PEI or PAI in adults with early HCC.

SEARCH STRATEGY

A systematic search was performed in The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and ISI Web of Science in May 2009. Meeting abstracts of six oncological and hepatological societies (ASCO, ESMO, ECCO, AASLD, EASL, APASL) and references of articles were handsearched. Researchers in the field were contacted.

SELECTION CRITERIA

Randomised trials comparing PEI or PAI with no intervention, sham intervention, other percutaneous interventions or surgery for the treatment of early HCC were considered regardless of blinding, publication status, or language. Studies comparing RFTA or combination treatments were excluded.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials for inclusion, and extracted and analysed data. The hazard ratios for median overall survival and recurrence-free survival were calculated using the Cox regression model with Parmar's method. Type and number of adverse events were reported descriptively.

MAIN RESULTS

Three randomised trials with a total of 261 patients were eligible for inclusion. The risk of bias was high in all trials. Two of the trials compared PEI with PAI. Overall survival (HR 1.47; 95% confidence interval (CI) 0.68 to 3.19) and recurrence-free survival (HR 1.42; 95% CI 0.68 to 2.94) were not significantly different. Data on the duration of hospital stay were inconclusive. Data on quality of life were not available. There were only mild adverse events in both treatment modalities.The other trial compared PEI with surgery. There was no significant difference in overall survival (HR 1.57; 95% CI 0.53 to 4.61) and recurrence-free survival (HR 1.35; 95% CI 0.69 to 2.63). No serious adverse events were reported in the PEI group. Three postoperative deaths occurred in the surgery group.

AUTHORS' CONCLUSIONS

PEI and PAI does not differ significantly regarding benefits and harms in patients with early HCC, but only a limited number of patients have been examined and the bias risk was high in all trials. There is also insufficient evidence to determine whether PEI or segmental liver resection is more effective, although PEI may seem safer.

Anti-angiogenic therapies for metastatic colorectal cancer

BACKGROUND

Angiogenesis inhibitors have been developed to block tumour angiogenesis and target vascular endothelial cells. While some of them have already been approved by the health authorities and are successfully integrated into patient care, many others are still under development, and the clinical value of this approach has to be established.

OBJECTIVES

To assess the efficacy and toxicity of targeted anti-angiogenic therapies, in addition to chemotherapy, in patients with metastatic colorectal cancer. Primary endpoints are both progression-free and overall survival. Response rates, toxicity and secondary resectability were secondary endpoints. Comparisons were first-line chemotherapy in combination with angiogenesis inhibitor, to the same chemotherapy without angiogenesis inhibitor; and second-line chemotherapy, to the same chemotherapy without angiogenesis inhibitor.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, as well as proceedings from ECCO, ESMO and ASCO until November 2008. In addition, reference lists from trials were scanned, experts in the field and drug manufacturers were contacted to obtain further information.

SELECTION CRITERIA

Randomized controlled trials on targeted anti-angiogenic drugs in metastatic colorectal cancer (MCRC).

DATA COLLECTION AND ANALYSIS

Data collection and analysis was performed, according to a previously published protocol. Because individual patient data was not provided, aggregate data had to be used for the analysis. Summary statistics for the primary endpoints were hazard ratios (HR's) and their 95% confidence intervals.

MAIN RESULTS

At present, eligible first line trials for this meta-analysis were available for bevacizumab (5 trials including 3101 patients) and vatalanib (1 trial which included 1168 patients). The overall HR s for PFS (0.61, 95% CI 0.45 - 0.83) and OS (0.81, 95% 0.73 - 0.90) for the comparison of first-line chemotherapy, with or without bevacizumab, confirms significant benefits in favour of the patients treated with bevacizumab. However, the effect on PFS shows significant heterogeneity. For second-line chemotherapy, with or without bevacizumab, a benefit in both PFS (HR 0.61, 95% CI 0.51 - 0.73) and OS (HR 0.75, 95% CI 0.63-0.89) was demonstrated in a single, randomized trial. While differences in treatment-related deaths and 60-day mortality were not significant, higher incidences in grade III/IV hypertension, arterial thrombembolic events and gastrointestinal perforations were observed in the patients treated with bevacizumab. For valatanib, currently available data showed a non-significant benefit in PFS and OS.

AUTHORS' CONCLUSIONS

The addition of bevacizumab to chemotherapy of metastatic colorectal cancer prolongs both PFS and OS in first-and second-line therapy.

Evolution of the randomized controlled trial in oncology over three decades

PURPOSE

The randomized controlled trial (RCT) is the gold standard for establishing new therapies in clinical oncology. Here we document changes with time in design, sponsorship, and outcomes of oncology RCTs.

METHODS

Reports of RCTs evaluating systemic therapy for breast, colorectal (CRC), and non-small-cell lung cancer (NSCLC) published 1975 to 2004 in six major journals were reviewed. Two authors abstracted data regarding trial design, results, and conclusions. Conclusions of authors were graded using a 7-point Likert scale. For each study the effect size for the primary end point was converted to a summary measure.

RESULTS

A total of 321 eligible RCTs were included (48% breast, 24% CRC, 28% NSCLC). Over time, the number and size of RCTs increased considerably. For-profit/mixed sponsorship increased substantially during the study period (4% to 57%; P < .001). There was increasing use of time-to-event measures (39% to 78%) and decreasing use of response rate (54% to 14%) as primary end point (P < .001). Effect size remained stable over the study period. Authors have become more likely to strongly endorse the experimental arm (P = .017). A significant P value for the primary end point and industry sponsorship were each independently associated with endorsement of the experimental agent (odds ratio [OR] = 19.6, 95% CI, 8.9 to 43.1, and OR = 3.5, 95% CI, 1.6 to 7.5, respectively).

CONCLUSION

RCTs in oncology have become larger and are more likely to be sponsored by industry. Authors of modern RCTs are more likely to strongly endorse novel therapies. For-profit sponsorship and statistically significant results are independently associated with endorsement of the experimental arm.

Treatment success in cancer: new cancer treatment successes identified in phase 3 randomized controlled trials conducted by the National Cancer Institute-sponsored cooperative oncology groups, 1955 to 2006

BACKGROUND

The evaluation of research output, such as estimation of the proportion of treatment successes, is of ethical, scientific, and public importance but has rarely been evaluated systematically. We assessed how often experimental cancer treatments that undergo testing in randomized clinical trials (RCTs) result in discovery of successful new interventions.

METHODS

We extracted data from all completed (published and unpublished) phase 3 RCTs conducted by the National Cancer Institute cooperative groups since their inception in 1955. Therapeutic successes were determined by (1) assessing the proportion of statistically significant trials favoring new or standard treatments, (2) determining the proportion of the trials in which new treatments were considered superior to standard treatments according to the original researchers, and (3) quantitatively synthesizing data for main clinical outcomes (overall and event-free survival).

RESULTS

Data from 624 trials (781 randomized comparisons) involving 216 451 patients were analyzed. In all, 30% of trials had statistically significant results, of which new interventions were superior to established treatments in 80% of trials. The original researchers judged that the risk-benefit profile favored new treatments in 41% of comparisons (316 of 766). Hazard ratios for overall and event-free survival, available for 614 comparisons, were 0.95 (99% confidence interval [CI], 0.93-0.98) and 0.90 (99% CI, 0.87- 0.93), respectively, slightly favoring new treatments. Breakthrough interventions were discovered in 15% of trials.

CONCLUSIONS

Approximately 25% to 50% of new cancer treatments that reach the stage of assessment in RCTs will prove successful. The pattern of successes has become more stable over time. The results are consistent with the hypothesis that the ethical principle of equipoise defines limits of discoverability in clinical research and ultimately drives therapeutic advances in clinical medicine.

Hypoxic radiosensitization: adored and ignored

Since observations from the beginning of the last century, it has become well established that solid tumors may contain oxygen-deficient hypoxic areas and that cells in such areas may cause tumors to become radioresistant. Identifying hypoxic cells in human tumors has improved by the help of new imaging and physiologic techniques, and a substantial amount of data indicates the presence of hypoxia in many types of human tumors, although with a considerable heterogeneity among individual tumors. Controlled clinical trials during the last 40 years have indicated that this source of radiation resistance can be eliminated or modified by normobaric or hyperbaric oxygen or by the use of nitroimidazoles as hypoxic radiation sensitizers. More recently, attention has been given to hypoxic cytotoxins, a group of drugs that selectively or preferably destroys cells in a hypoxic environment. An updated systematic review identified 10,108 patients in 86 randomized trials designed to modify tumor hypoxia in patients treated with curative attempted primary radiation therapy alone. Overall modification of tumor hypoxia significantly improved the effect of radiotherapy, with an odds ratio of 0.77 (95% CI, 0.71 to 0.86) for the outcome of locoregional control and with an associated significant overall survival benefit (odds ratio = 0.87; 95% CI, 0.80 to 0.95). No significant influence was found on the incidence of distant metastases or on the risk of radiation-related complications. Ample data exist to support a high level of evidence for the benefit of hypoxic modification. However, hypoxic modification still has no impact on general clinical practice.

Electric stimulation and hyperbaric oxygen therapy in the treatment of nonunions

Up to 10% of the fractures occurring annually in the U.S. end up in non-union or delayed union. Classical treatment with osteosynthesis and bone grafting is not always successful. Alternatives in treatment have long ago been considered. This article presents current concepts in treatment with electrical stimulation and hyperbaric oxygen, the mechanisms of action, experimental and clinical evidence of their application.

Are experimental treatments for cancer in children superior to established treatments? Observational study of randomised controlled trials by the Children's Oncology Group

OBJECTIVES

To assess how often new treatments for childhood cancer assessed in phase III randomised trials are superior or inferior to standard treatments and whether the pattern of successes and failures in new treatments is consistent with uncertainty being the ethical basis for enrolling patients in such trials.

DESIGN

Observational study.

SETTING

Phase III randomised controlled trials carried out under the aegis of the Children's Oncology Group between 1955 and 1997, regardless of whether they were published.

MAIN OUTCOME MEASURES

Overall survival, event free survival, and treatment related mortality.

RESULTS

126 trials were included, involving 152 comparisons and 36,567 patients. The odds ratio for overall survival with experimental treatments was 0.96 (99% confidence interval 0.89 to 1.03), indicating that new treatments are as likely to be inferior as they are to be superior to standard treatments. This result was not affected by publication bias, methodological quality, treatment type, disease, or comparator.

CONCLUSIONS

New treatments in childhood cancer tested in randomised controlled trials are, on average, as likely to be inferior as they are to be superior to standard treatments, confirming that the uncertainty principle has been operating.

Trends in UK cancer trials: results from the UK Coordinating Committee for Cancer Research National Register of Cancer Trials

We aimed to study trends in the design and conduct of randomised controlled trials (RCTs) in cancer in the UK, using the UK Coordinating Committee for Cancer Research (UKCCCR) National Register of Cancer Trials (NRCT). We conducted a descriptive survey of 520 UK RCTs in cancer that were registered on the UKCCCR NRCT. All trials had been initiated between 1971 and 2000. Trials on the NRCT have been conducted in a wide variety of cancer types, but with a third in breast (22%) or lung cancer (11%). They have largely been funded by the UK public and charity sectors. Overall, there has been a sustained rise in the total numbers of patients entering UK cancer trials over time with a trend towards larger, multicentre trials, greater recruitment targets and a marked reduction in the average time taken to complete trials. Trends in the design and conduct of noncommercial cancer RCTs from 1971 to 2000 are encouraging. It will be interesting to see how they develop in light of the implementation of recent national initiatives regarding cancer clinical trials in the UK.

Chemotherapy for advanced gastric cancer

BACKGROUND

Gastric cancer currently ranks second in global cancer mortality. Most patients are either diagnosed at an advanced stage, or develop a relapse after apparently curative operation. Apart from supportive measures, systemic chemotherapy is the only treatment option available in this situation.

OBJECTIVES

To assess the effect of chemotherapy versus best supportive care, combination versus single agent chemotherapy and different combination chemotherapy regimens in advanced gastric cancer.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 1, 2004), MEDLINE and EMBASE up to February 2004 and reference lists of articles. We also contacted pharmaceutical companies as well as national and international experts.

SELECTION CRITERIA

Randomised controlled trials on systemic intravenous chemotherapy versus best supportive care, combination versus single agent chemotherapy and different combination chemotherapies in advanced gastric cancer.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data. A third investigator was consulted in case of disagreements. We contacted study authors to obtain missing information.

MAIN RESULTS

Chemotherapy versus best supportive care consistently demonstrated a significant benefit in terms of overall survival in favour of the group receiving chemotherapy (Hazard Ratios (HR) 0.39; 95% confidence intervals (CI) 0.28 to 0.52). Combination versus single-agent chemotherapy provides evidence for a survival benefit in favour of combination chemotherapy (HR 0.85; 95% CI 0.76 to 0.96). Numbers included in these comparisons were 184 and 1338 participants respectively. This benefit is achieved at the price of increased toxicity in the combination chemotherapy arms. When comparing 5-FU/cisplatin-containing combination therapy regimens with anthracyclines versus those without anthracyclines (HR 0.77; 95% CI 0.62 to 0.95 based on 501 participants) and 5-FU/anthracycline-containing combinations with cisplatin versus those without cisplatin (HR 0.83; 95% CI 0.76 to 0.91 based on 1147 participants), there was a significant survival benefit for regimens including 5-FU, anthracyclines and cisplatin.

AUTHORS' CONCLUSIONS

Chemotherapy significantly improves survival in comparison to best supportive care. In addition, combination chemotherapy improves survival compared to single-agent 5-FU, but the effect size is much smaller. Among the combination chemotherapy regimens studied, best survival results are achieved with regimens containing 5-FU, anthracyclines and cisplatin. In this category, ECF (epirubicin, cisplatin and continuous infusion 5-FU) is tolerated best.

Evaluation of new treatments in radiation oncology: are they better than standard treatments?

CONTEXT

The superiority of innovative over standard treatments is not known. To describe accurately the outcomes of innovations that are tested in randomized controlled trials (RCTs) 3 factors have to be considered: publication rate, quality of trials, and the choice of the adequate comparator intervention.

OBJECTIVE

To determine the success rate of innovative treatments by assessing preferences between experimental and standard treatments according to original investigators' conclusions, determining the proportion of RCTs that achieved primary outcomes' statistical significance, and performing meta-analysis to examine if the summary point estimate favored innovative vs standard treatments.

DATA SOURCES

Randomized controlled trials conducted by the Radiation Therapy Oncology Group (RTOG).

STUDY SELECTION

All completed phase 3 trials conducted by the RTOG since its creation in 1968 until 2002. For multiple publications of the same study, we used the one with the most complete primary outcomes and with the longest follow-up information.

DATA EXTRACTION

We used the US National Cancer Institute definition of completed studies to determine the publication rate. We extracted data related to publication status, methodological quality, and treatment comparisons. One investigator extracted the data from all studies and 2 independent investigators extracted randomly about 50% of the data. Disagreements were resolved by consensus during a meeting.

DATA SYNTHESIS

Data on 12,734 patients from 57 trials were evaluated. The publication rate was 95%. The quality of trials was high. We found no evidence of inappropriateness of the choice of comparator. Although the investigators judged that standard treatments were preferred in 71% of the comparisons, when data were meta-analyzed innovations were as likely as standard treatments to be successful (odds ratio for survival, 1.01; 99% confidence interval, 0.96-1.07; P = .5). In contrast, treatment-related mortality was worse with innovations (odds ratio, 1.76; 99% confidence interval, 1.01-3.07; P = .008). We found no predictable pattern of treatment successes in oncology: sometimes innovative treatments are better than the standard ones and vice versa; in most cases there were no substantive differences between experimental and conventional treatments.

CONCLUSION

The finding that the results in individual trials cannot be predicted in advance indicates that the system and rationale for RCTs is well preserved and that successful interventions can only be identified after an RCT is completed.

Satisfaction of the uncertainty principle in cancer clinical trials: retrospective cohort analysis

OBJECTIVE

To assess whether publicly funded adult cancer trials satisfy the uncertainty principle, which states that physicians should enroll a patient in a trial only if they are substantially uncertain which of the treatments in the trial is most appropriate for the patient. This principle is violated if trials systematically favour either the experimental or the standard treatment.

DESIGN

Retrospective cohort study of completed cancer trials, with randomisation as the unit of analysis.

SETTING

Two cooperative research groups in the United States.

STUDIES INCLUDED

93 phase III randomised trials (103 randomisations) that completed recruitment of patients between 1981 and 1995.

MAIN OUTCOME MEASURES

Whether the randomisation favoured the experimental treatment, the standard treatment, or neither treatment; effect size (outcome of the experimental treatment compared with outcome of the standard treatment) for each randomisation.

RESULTS

Three randomisations (3%) favoured the standard treatment, 70 (68%) found no significant difference between treatments, and 30 (29%) favoured the experimental treatment. The average effect size was 1.20 (95% confidence interval 1.13 to 1.28), reflecting a slight advantage for the experimental treatment.

CONCLUSIONS

In cooperative group trials in adults with cancer, there is a measurable average improvement in disease control associated with assignment to the experimental rather than the standard arm. However, the heterogeneity of outcomes and the small magnitude of the advantage suggest that, as a group, these trials satisfy the uncertainty principle.

On the evolution of statistical methods as applied to clinical trials

This paper describes how statistical methods have evolved in parallel with activities associated with randomized control trials. In particular we emphasize the pivotal role of two papers published in British Journal of Cancer, and the paper describing the Cox proportional hazards model. In addition, the importance of early papers on estimating the sample size required for trials is highlighted. Later developments including the increasing roles for competing risks, multilevel modelling and Bayesian methodologies are described. The interplay between computer software and statistical methodological developments is stressed. Finally some future directions are indicated.

Choosing a control intervention for a randomised clinical trial

BACKGROUND

Randomised controlled clinical trials are performed to resolve uncertainty concerning comparator interventions. Appropriate acknowledgment of uncertainty enables the concurrent achievement of two goals : the acquisition of valuable scientific knowledge and an optimum treatment choice for the patient-participant. The ethical recruitment of patients requires the presence of clinical equipoise. This involves the appropriate choice of a control intervention, particularly when unapproved drugs or innovative interventions are being evaluated.

DISCUSSION

We argue that the choice of a control intervention should be supported by a systematic review of the relevant literature and, where necessary, solicitation of the informed beliefs of clinical experts through formal surveys and publication of the proposed trial's protocol.

SUMMARY

When clinical equipoise is present, physicians may confidently propose trial enrollment to their eligible patients as an act of therapeutic beneficence.

Importance of hypoxia in the biology and treatment of brain tumors

The resistance of gliomas to treatment with radiation and antineoplastic drugs may result in part from the effects of the extensive, severe hypoxia that is present in these tumors. It is clear that brain tumors contain extensive regions in which the tumor cells are subjected to unphysiological levels of hypoxia. Hypoxic cells are resistant to radiation. Hypoxia and the perfusion deficits and metabolic changes that accompany hypoxia in vivo also produce resistance to many commonly used anticancer drugs. The resistance of cells that are hypoxic at the time of therapy may influence the efficacy of the treatment of these tumors with radiation, chemotherapy, and combined modality regimens. Moreover, it is becoming increasingly evident from laboratory studies that exposure of cells to adverse microenvironments produces transient changes in gene expression, induces mutations, and selects for cells with altered genotypes, thus driving the evolution of the cell population toward increasing malignancy and increasingly aggressive phenotypes. Hypoxia may therefore be involved in the evolution of cells in low-grade malignancies to the resistant, aggressive phenotype characteristic of glioblastomas. During the past 50 years, many attempts have been made to circumvent the therapeutic resistance induced by hypoxia, by improving tumor oxygenation, by using oxygen-mimetic radiosensitizers, by adjuvant therapy with drugs that are preferentially toxic to hypoxic cells, by using hyperthermia, or by devising radiation sources and regimens that are less affected by hypoxia. Past clinical trials have provided tantalizing suggestions that the outcome of therapy can be improved by many of these approaches, but none has yet produced a significant, reproducible improvement in the therapeutic ratio, which would be needed for any of these approaches to become the standard therapy for these diseases. Several ongoing clinical trials are addressing other, hopefully better regimens; it will be interesting to see the results of these studies.

Acknowledgment of uncertainty: a fundamental means to ensure scientific and ethical validity in clinical research

Recognition of the importance of uncertainty in the design of randomized, controlled trials (RCT) has reached the status of a principle. The "uncertainty principle," or less ambiguously, equipoise, holds that a patient should be enrolled in an RCT only if there is substantial uncertainty about which of the trial treatments would benefit the patient most. In fact, the "uncertainty principle" addresses the most important issue of a clinical trial--the choice of an adequate comparative control. Studies in which intervention and control group are believed to be non-equivalent violate the uncertainty principle. Therefore, one would expect that both editors and authors would be particularly careful to include a statement concerning prior beliefs of the investigator(s) about the uncertainty of the treatments that are reported. However, we found no evidence of such a policy in the randomized, controlled trials we examined. We also show that there is a predictable relationship between the uncertainty principle, that is, the moral principle upon which trials are based, and the ultimate outcomes of clinical trials. We postulate that about 50% of innovations are successful, leading to the conclusion that preserving the ethics of clinical research may be the best investment strategy available.

Anorectal injury following pelvic radiotherapy

BACKGROUND

Current knowledge of the effects of radiation on the anorectum is based on a limited number of studies. Variability in delivery techniques, both currently and historically, combined with a paucity of prospective and randomized studies makes interpretation of the literature difficult. This review presents the existing evidence and identifies areas that require further work.

METHODS

This review is based on a literature search (Medline and PubMed) and manual cross-referencing.

RESULTS AND CONCLUSION

More than three-quarters of patients receiving pelvic radiotherapy experience acute anorectal symptoms and up to one-fifth suffer from late-phase radiation proctitis. About 5 per cent develop other chronic complications, such as fistula, stricture and disabling faecal incontinence. The risk of rectal cancer may be increased. Conservative treatment options are of limited value. Surgery may be considered if symptoms are severe, provided sphincter function is adequate and recurrent disease is excluded. Large prospective studies with accurate dosimetric data and long-term follow-up are needed to provide meaningful information on which to base new strategies to minimize the side-effects from radiotherapy.

Trends in acute ischemic stroke trials through the 20th century

BACKGROUND AND PURPOSE

The advent of controlled clinical trials revolutionized clinical medicine over the course of the 20th century. The objective of this study was to quantitatively characterize developments in clinical trial methodology over time in the field of acute ischemic stroke.

METHODS

All controlled trials targeting acute ischemic stroke with a final report in English were identified through MEDLINE and international trial registries. Data regarding trial design, implementation, and results were extracted. A formal 100-point scale was used to rate trial quality.

RESULTS

A total of 178 controlled acute stroke trials were identified, encompassing 73 949 patients. Eighty-eight trials involved neuroprotective agents, 59 rheological/antithrombotic agents, 26 agents with both neuroprotective and rheological/antithrombotic effects, and 5 a nonpharmacological intervention. Only 3 trials met conventional criteria for a positive outcome. Between the 1950s and 1990s, the number of trials per decade increased from 3 to 99, and mean trial sample size increased from 38 (median, 26) to 661 (median, 113). During 1980-1999, median time window allowed for enrollment decreased per half decade from 48 to 12 hours. Reported pharmaceutical sponsorship increased substantially over time, from 38% before 1970 to 68% in the 1990s. Trial quality improved substantially from a median score of 12 in the 1950s to 72 in the 1990s.

CONCLUSIONS

Accelerating trends in acute stroke controlled trials include growth in number, sample size, and quality, and reduction in entry time window. These changes reflect an increased understanding of the pathophysiology of acute stroke, the imperative for treatment initiation within a critical time window, and more sophisticated trial design.

Closeout of four phase II Vanguard trials and patient rollover into a large international phase III HIV clinical endpoint trial

Large phase III clinical trials typically require many years of planning and preparation. During this time, proposed study methods and overall trial feasibility can be assessed in smaller pilot studies. However, the patients enrolled in these pilot studies are not routinely included in the larger study. In preparation for a multinational randomized clinical end point trial of interleukin-2 in HIV-infected patients, four phase II "Vanguard" studies were initiated. These Vanguard trials served to increase safety and surrogate marker data in diverse patient cohorts, increase clinical experience with the study medication, and identify the optimal dose of medication for the phase III trial. These trials also served to assess patient recruitment potential and to develop international clinical trial coordination experience. The Vanguard trials were designed to allow continued follow-up of their patients as participants of the phase III trial once the feasibility of the phase III trial was confirmed. The purpose of this paper is to describe the steps taken in the closeout of these four phase II trials while reconsenting these patients to the phase III trial. Specifically, the reconsent process, the data collection transition plan, and the steps taken to minimize bias due to differential reconsent according to the assigned treatment arm in the phase II trial are described. The procedures employed are relevant to the reconsent of patients for long-term follow-up at the completion of clinical trials. Control Clin Trials 2001;22:42-48

The uncertainty principle and industry-sponsored research

BACKGROUND

Reporting of pharmaceutical-industry-sponsored randomised clinical trials often result in biased findings, either due to selective reporting of studies with non-equivalent arms or publication of low-quality papers, wherein unfavourable results are incompletely described. A randomised trial should be conducted only if there is substantial uncertainty about the relative value of one treatment versus another. Studies in which intervention and control are thought to be non-equivalent violates the uncertainty principle.

METHODS

We examined the quality of 136 published randomised trials that focused on one disease category (multiple myeloma) and adherence to the uncertainty principle. To evaluate whether the uncertainty principle was upheld, we compared the number of studies favouring experimental treatments over standard ones. We analysed data according to the source of funding.

FINDINGS

Trials funded solely or in part by 35 profit-making organisations had a trend toward higher quality scores (mean 2.94 [SD 1.3]; median 3) than randomised trials supported by 95 governmental or other non-profit organisations (2.4 [0.8]; 2; p=0.06). Overall, the uncertainty principle was upheld, with 44% of randomised trials favouring standard treatments and 56% innovative treatments (p=0.17); mean and median preference evaluation scores were 3.7 (1.0) and 4. However, when the analysis was done according to the source of funding, studies funded by non-profit organisations maintained equipoise favouring new therapies over standard ones (47% vs 53%; p=0.608) to a greater extent than randomised trials supported solely or in part by profit-making organisations (74% vs 26%; p=0.004).

INTERPRETATION

The reported bias in research sponsored by the pharmaceutical industry may be a consequence of violations of the uncertainty principle. Sponsors of clinical trials should be encouraged to report all results and to choose appropriate comparative controls.