Preoperative Chemoradiation Therapy With Capecitabine/Oxaliplatin and Cetuximab in Rectal Cancer: Long-Term Results of a Prospective Phase 1/2 Study

Somatic pharmacogenomics in the treatment prognosis of locally advanced rectal cancer patients: a narrative review of the literature

INTRODUCTION

Standard treatment for patients with locally advanced rectal cancer (LARC) includes neoadjuvant chemoradiotherapy (nCRT) with fluoropyrimidines, followed by surgical excision. The newly introduced therapeutic strategies propose intensified regimens or more conservative approaches based on risk stratification algorithms that currently include clinicoradiological criteria but not molecular variables. How to better stratify patients is a burning clinical question, and pharmacogenomics may prove useful in identifying new genetic markers that could be incorporated into clinical algorithms to personalize nCRT. An emerging area could be the evaluation of somatic mutations as potential genetic markers that correlate with patient prognosis. Tumor mutations in the RAS/BRAF genes, as well as microsatellite instability (MSI) status, are currently used in treatment selection for colorectal cancer (CRC); however, their clinical value in LARC is still unclear.

AREA COVERED

This literature review discusses the relevant findings on the prognostic role of mutations in the key oncogenes RAS, KRAS, BRAF, PIK3CA, SMAD4 and TP53, including MSI status in LARC patients treated with nCRT.

EXPERT OPINION

KRAS proved to be the most promising marker, consistently associated with poorer disease-free survival and overall survival. Therefore, KRAS could be a good candidate for integration into the risk stratification algorithm to develop a personalized treatment.

Neoadjuvant therapy of cetuximab combined with chemoradiotherapy in rectal cancer: A single-arm meta-analysis of noncomparative clinical studies and randomized controlled trials

OBJECTIVE

Preoperative chemoradiotherapy combined with radical resection has reduced local recurrence rates in rectal cancer. Cetuximab shows improvement in rectal cancer treatment. But the role for neoadjuvant therapy of cetuximab combined with chenmoradiotherapy in rectal cancer remains unclear. The present study aimed to use meta-analytical techniques to assess its benefit and risk.

MATERIALS AND METHODS

We searched PubMed, the Cochrane Library, Embase to identify the correlational non-comparative clinical studies and randomized controlled trials (RCTs). The primary endpoints of interest were pathological complete response (pCR), complete response (CR), partial response (PR), stable disease, progressive disease (PD), R0-resection, R1-resection, and R2-resection. The secondary included any grade of toxicity.

RESULTS

Eleven investigations (9 noncomparative open-label cohort studies and 2 randomized controlled trials) involving 550 patients were ultimately included. The pooled estimates of pCR was 10% (95% confidence interval [CI]: 7%-13%, I2 = 55.9%). Simultaneously, only a small amount of patients achieved CR (11%, 95% CI: 7%-15%, I2 = 44.0%), which was consistent with pCR. Besides, R0 resection (93%, 95% CI: 90%-96%, I2 = 16.5%) seemed to be increased but need further exploration. The safety was also calculated, and most of the toxicities were moderate.

CONCLUSION

Neoadjuvant therapy of cetuximab combined with chemoradiotherapy could not improve pCR. The raise of R0-resection rate needed to be verified by more high-quality and well-designed RCTs. Meanwhile, the morbidity of toxicity was relatively mild and acceptable.

Long-term quality of life after preoperative radiochemotherapy in patients with localized and locally advanced breast cancer

BACKGROUND

Preoperative radiotherapy (PRT) or radiochemotherapy (PRCT) is used in different tumor sites. The aim of the study was to examine the long-term quality of life (QoL) of localized / locally advanced breast cancer patients treated with PRT/PRCT followed by breast-conserving surgery (BCS) or mastectomy (ME).

METHODS

Assessment of QoL was done using EORTC QLQ-C30 questionnaires for overall QoL and EORTC QLQ-BR23 for breast-specific QoL. The summary scores were categorized into 4 distinct groups to classify the results. Furthermore, a comparative analysis was performed between the study cohort and a previously published reference cohort of healthy adults. We assessed the impact of different clinical, prognostic, and treatment-related factors on selected items from C30 and BR23 using a dependence analysis.

RESULTS

Out of 315 patients treated with PRT/PCRT in the years 1991 to 1999, 203 patients were alive at long-term follow-up after a mean of 17.7 years (range 14-21). 37 patients were lost to follow-up and 61 patients refused to be contacted, leading to 105 patients (64 patients after BCS and 41 after ME) being willing to undergo further clinical assessment regarding QoL outcome. Overall, QoL (QLQ-C30) was rated "excellent" or "good" in 85% (mean value) of all patients (BCS 83%, ME 88%). Comparative analysis between the study cohort and a published healthy control group revealed significantly better global health status and physical and role functioning scores in the PRT/PRCT group. The analysis demonstrates no differences in nausea/vomiting, dyspnea, insomnia, constipation, or financial difficulties. According to the dependence analysis, global QoL was associated with age, operation type and ME reconstruction.

CONCLUSION

We did not detect any inferiority of PRT/PRCT compared to a healthy reference group with no hints of a detrimental long-term effect on general and breast-specific quality of life.

Systematic review of treatment intensification using novel agents for chemoradiotherapy in rectal cancer

BACKGROUND

With the well established shift to neoadjuvant treatment for locally advanced rectal cancer, there is increasing focus on the use of radiosensitizers to improve the efficacy and tolerability of radiotherapy. There currently exist few randomized data exploring novel radiosensitizers to improve response and it is unclear what the clinical endpoints of such trials should be.

METHODS

A qualitative systematic review was performed according to the PRISMA guidelines using preset search criteria across the PubMed, Cochrane and Scopus databases from 1990 to 2017. Additional results were generated from the reference lists of included papers.

RESULTS

A total of 123 papers were identified, of which 37 were included; a further 60 articles were obtained from additional referencing to give a total of 97 articles. Neoadjuvant radiosensitization for locally advanced rectal cancer using fluoropyrimidine-based chemotherapy remains the standard of treatment. The oral derivative capecitabine has practical advantages over 5-fluorouracil, with equal efficacy, but the addition of a second chemotherapeutic agent has yet to show a consistent significant efficacy benefit in randomized clinical assessment. Preclinical and early-phase trials are progressing with promising novel agents, such as small molecular inhibitors and nanoparticles.

CONCLUSION

Despite extensive research and promising preclinical studies, a definite further agent in addition to fluoropyrimidines that consistently improves response rate has yet to be found.

A review of preoperative chemoradiotherapy for lower rectal cancer

In Western countries, rectal cancer has been treated by chemoradiotherapy (CRT) for several decades now, and good local control has been reported. However, Japanese guidelines did not strongly recommend CRT, because CRT is only useful for achieving local control and imbues no survival benefit. For this reason, CRT was rarely used to treat rectal cancer in Japan. However, in the 2000s, several studies involving CRT began to be reported from Western countries, such as “correlation between pathological complete response and survival,” “induction chemotherapy followed by CRT,” and “watch-and-wait policies.” These studies were directly correlated with survival of and benefits to the patients. Given these findings, Japanese institutions have recently begun to introduce CRT for rectal cancer. Therefore, in the present study, we reviewed several topics regarding CRT for rectal cancer.

Current issues of preoperative radio(chemo)therapy and its future evolution in locally advanced rectal cancer

Neoadjuvant therapies are effective for local control and tumor downstaging. Up to date, preoperative long-course chemoradiotherapy and short-course radiotherapy are the two primary guideline-recommended neoadjuvant therapies for locally advanced rectal cancer patients. However, clinicians throughout the world are trying their best to further optimize the regimens and concepts of neoadjuvants. Hence, there is an urgent need to summarize evidence regarding indications of neaoadjuvant therapies and relative merits of current standard regimens. In addition, we also reviewed the optimized regimens mainly based on short-course radiotherapy with delayed surgery, consolidation chemotherapy, induction chemotherapy, chemotherapy alone without radiation and concepts in terms of organ preservation and personalized treatments to further explore the future evolution of neoadjuvant therapies in rectal cancer.

Targeted agents in GI radiotherapy: Clinical efficacy and side effects

Approximately 50% of all patients with cancer receive radiotherapy (RT) at some point during their treatment. Despite the advent of modern imaging and advances in planning and delivering highly-conformal and precise RT, further dose escalation to improve clinical outcome is often limited by the potential side-effects to adjacent tissues. Addition of chemotherapy to radiotherapy (CRT) has led to significant clinical improvements in many gastrointestinal malignancies but at the expense of increased toxicity as most chemotherapy drugs lack specificity. Targeted agents modulate specific biological pathways and can potentially enhance RT efficacy. However, so far, the majority of clinical studies incorporating targeted agents into RT and CRT have produced disappointing results in gastrointestinal malignancies. Also, we lack validated biomarkers and methods for monitoring and predicting the efficacy of these agents when combined with RT/CRT. In the present article, we will review the most important targeted therapies, and examine the efficacy and toxicity of these agents when combined with RT/CRT in gastrointestinal malignancies. The shortcomings as well as future challenges and perspectives for the successful use of these compounds with RT/CRT in future trials will also be outlined.

Phase 1 Study of Preoperative Chemoradiation Therapy With Temozolomide and Capecitabine in Patients With Locally Advanced Rectal Cancer

PURPOSE

Preoperative chemoradiation therapy (CRT) with capecitabine is a standard treatment strategy in patients with locally advanced rectal cancer (LARC). Temozolomide improves the survival of patients with glioblastoma with hypermethylated O(6)-methylguanine DNA methyltransferase (MGMT); MGMT hypermethylation is one of the colorectal carcinogenesis pathways. We aimed to determine the dose-limiting toxicity (DLT) and recommended dose (RD) of temolozomide in combination with capecitabine-based preoperative CRT for LARC.

METHODS AND MATERIALS

Radiation therapy was delivered with 45 Gy/25 daily fractions with coned-down boost of 5.4 Gy/3 fractions. Concurrent chemotherapy comprised fixed and escalated doses of capecitabine and temozolomide, respectively. The MGMT hypermethylation was evaluated in pretreatment tumor samples. This trial is registered with ClinicalTrials.gov with the number NCT01781403.

RESULTS

Twenty-two patients with LARC of cT3-4N0 or cTanyN1-2 were accrued. Dose level 3 was chosen as the RD because DLT was noticeably absent in 10 patients treated up to dose level 3. An additional 12 patients were recruited in this group. Grade III adverse events were noted, and pathologic complete response (pCR) was observed in 7 patients (31.8%); MGMT hypermethylation was detected in 16. The pCR rate was 37.5% and 16.7% in the hypermethylated and unmethylated MGMT groups, respectively (P=.616).

CONCLUSIONS

There was a tendency toward higher pCR rates in patients with hypermethylated MGMT. Future randomized studies are therefore warranted.

Germline and somatic genetic predictors of pathological response in neoadjuvant settings of rectal and esophageal cancers: systematic review and meta-analysis

Oncologists have pointed out an urgent need for biomarkers that can be useful for clinical application to predict the susceptibility of patients to preoperative therapy. This review collects, evaluates and combines data on the influence of reported somatic and germline genetic variations on histological tumor regression in neoadjuvant settings of rectal and esophageal cancers. Five hundred and twenty-seven articles were identified, 204 retrieved and 61 studies included. Among 24 and 14 genetic markers reported for rectal and esophageal cancers, respectively, significant associations in meta-analyses were demonstrated for the following markers. In rectal cancer, major response was more frequent in carriers of the TYMS genotype 2 R/2 R-2 R/3 R (rs34743033), MTHFR genotype 677C/C (rs1801133), wild-type TP53 and KRAS genes. In esophageal cancer, successful therapy appeared to correlate with wild-type TP53. These results may be useful for future research directions to translate reported data into practical clinical use.

EGFR and β1-integrin targeting differentially affect colorectal carcinoma cell radiosensitivity and invasion

BACKGROUND AND PURPOSE

Simultaneous targeting of β1 integrin receptor and epidermal growth factor receptor (EGFR) showed higher level of radiosensitization in head and neck cancers than monotherapies. As EGFR inhibition is similarly performed in colorectal cancer (CRC), we investigated the radiosensitizing and anti-invasive potential of β1-integrin/EGFR inhibition in CRC cell lines grown in more physiological three-dimensional (3D) matrix-based cell cultures.

MATERIALS AND METHODS

DLD-1 and HT-29 cells were used for 3D-colony formation, invasion and proliferation assays and Western blotting. β1 integrin, focal adhesion kinase and EGFR were inhibited by AIIB2, TAE226 and Cetuximab, respectively. KRAS and BRAF knockdown were accomplished using small-interfering RNA technology. Single doses of X-rays ranged from 2Gy to 6Gy and 5-fluorouracil (5-FU) concentration was 10μM.

RESULTS

Neither β1-integrin/EGFR inhibition nor KRAS or BRAF depletion nor 5-FU significantly modified CRC cell radiosensitivity. Cetuximab, AIIB2 and Cetuximab/AIIB2 differentially modulated MAPK, JNK and AKT phosphorylation. AIIB2 and TAE226 significantly decreased cell invasion.

CONCLUSIONS

Our data show inefficiency of Cetuximab and AIIB2 on top of radiochemotherapy. The functions of KRAS and BRAF in therapy resistance remain unanswered and warrant further preclinical molecular-driven investigations. One promising approach might be β1 integrin targeting for reducing metastatic CRC cell spread.

Feasibility of modified short-course radiotherapy combined with a chemoradiosensitizer for T3 rectal cancer

BACKGROUND

5-Fluorouracil-based chemotherapy is considered to be a radiosensitizer; however, conventional short-course radiotherapy combined with chemotherapy is generally thought to not be feasible because of the prevalence of side effects.

OBJECTIVE

The aim of this study was to evaluate the feasibility of modified short-course radiotherapy combined with a chemoradiosensitizer for T3 rectal cancer.

DESIGN AND SETTINGS

This study was retrospective in nature and used a prospectively collected database.

PATIENTS

Patients with T3 rectal cancer located below the peritoneum reflection were selected.

INTERVENTIONS

A total dose of 25 Gy of radiotherapy was administered in 10 fractions of 2.5 Gy each for 5 days. Radiotherapy was performed with S-1 as a radiosensitizer from day 1 to day 10. Surgery was targeted to be performed 4 weeks after radiotherapy.

MAIN OUTCOME MEASUREMENTS

The morbidity, sphincter-preserving rate, anal function, and long-term outcomes were assessed.

RESULTS

All patients (n = 170) completed the radiotherapy regimen and 166 (97.6%) completed the combination regimen with chemotherapy. A total of 149 patients (87.6%) had sphincter-preserving surgery (double stapling technique (DST), 58 patients; intersphincteric resection (ISR), 91 patients), and postoperative complications were relatively mild (anastomotic leakage, 15.4%; intra-abdominal infection, 8.2%). Among those undergoing sphincter preserving surgery, the 5-year local relapse-free survival rate was 94.3% in the DST group, and 89.8% in the ISR group. With respect to the anal function, the Wexner score the first year after stoma closure for the double-stapling technique group was 6 and that for intersphincteric resection was 15; however, the score for the intersphincteric resection group was improved to 8 at 4 years after stoma closure.

LIMITATIONS

This study had limitations because it was an uncontrolled, 1-arm, retrospective review with a small sample size.

CONCLUSIONS

Modified short-course radiotherapy combined with chemoradiosensitizer is a feasible approach for treating T3 rectal cancer. With the use of the short-course approach, efforts to reduce the incidence of side effects by appropriately prolonging the waiting period enable the administration of combination treatment with short-course radiotherapy and chemotherapy.

Does the Addition of Cetuximab to Radiochemotherapy Improve Outcome of Patients with Locally Advanced Rectal Cancer? Long-Term Results from Phase II Trials

Purpose. The addition of cetuximab to radiochemotherapy (RCT) failed to improve complete response rates in locally advanced rectal cancer (LARC). We report the long-term results in patients treated within two sequential clinical trials. Methods. Patients receiving neoadjuvant RCT using capecitabine and irinotecan (CapIri) within a phase I/II trial or CapIri + cetuximab within a phase II trial were evaluated for analysis of disease-free survival (DFS) and overall survival (OS). KRAS exon 2 mutational status had been analyzed in patients receiving cetuximab. Results. 37 patients from the CapIri trial and 49 patients from the CapIri-cetuximab treatment group were evaluable. Median follow-up time was 75.2 months. The 5-year DFS rate was 82% (CapIri) and 79% (CapIri-cetuximab) (P = 0.62). The median OS was 127.4 months. 5-year OS was 73% for both groups (CapIri and CapIri-cetuximab) (P = 0.61). No significant difference in DFS (P = 0.86) or OS (P = 0.39) was noticed between patients receiving CapIri and those receiving CapIri-cetuximab with KRAS wild-type tumors. Conclusions. As the addition of cetuximab did not improve neither DFS nor OS it should not play a role in the perioperative treatment of patients with LARC, not even of patients with (K)RAS WT tumors.

[Preoperative chemoradiotherapy for rectal cancer: experience from one centre]

PURPOSE

In recent decades, the management of rectal cancer has been significantly improved by optimizing the surgical treatment with the total mesorectal excision and the development of neoadjuvant radiotherapy with or without chemotherapy. In this study, we investigated the impact of changes in practice over a period of 15 years in an expert centre.

PATIENTS AND METHODS

A monocentric study was conducted retrospectively on cT3-resectable T4 patients who received chemoradiotherapy for a locally advanced rectal adenocarcinoma between 1993 and 2008. We studied sphincter preservation, pathological complete response (ypT0), survival, and toxicities by different concomitant chemotherapy and treatment period.

RESULTS

Among the 179 patients who had a chemoradiotherapy, 56.4% were received concomitant 5-fluoro-uracil-leucovorin, 28.5% with concomitant capecitabine, and 15.1% with concomitant oxaliplatin and capecitabine. The average dose of radiotherapy was 45 Gy (25×1.8 Gy). Five-year disease-free survival was 74.3% and overall survival 68.8%. The rate of local recurrence and distant metastases were 6.1 and 23.6%. In multivariate analysis, concomitant chemotherapy oxaliplatin and capecitabine improved the pathological complete response rate (ypT0; capecitabine: 6%, 5-fluoro-uracil-leucovorin: 10.3%, capecitabine-oxaliplatin: 22.2%), but not significantly (P=0.12) and with more toxicities, and treatment interruptions. Sphincter preservation rate was not improved significantly during the study period (1993-2004 vs. 2005-2008), but disease-free survival improved from 72.2% up to 87.5% (P=0.03).

CONCLUSION

Our results are consistent with those published in the literature. Concomitant chemotherapy with 5-fluoro-uracil or capecitabine remains the standard scheme. Upfront chemotherapy, before chemoradiotherapy, should be investigated with regard to the predominance of metastasis.

Trial Watch: Radioimmunotherapy for oncological indications

During the past two decades, it has become increasingly clear that the antineoplastic effects of radiation therapy do not simply reflect the ability of X-, β- and γ-rays to damage transformed cells and directly cause their permanent proliferative arrest or demise, but also involve cancer cell-extrinsic mechanisms. Indeed, among other activities, radiotherapy has been shown to favor the establishment of tumor-specific immune responses that operate systemically, underpinning the so-called 'out-of-field' or 'abscopal' effect. Thus, ionizing rays appear to elicit immunogenic cell death, a functionally peculiar variant of apoptosis associated with the emission of a particularly immunostimulatory combination of damage-associated molecular patterns. In line with this notion, radiation therapy fosters, and thus exacerbates, the antineoplastic effects of various treatment modalities, including surgery, chemotherapy and various immunotherapeutic agents. Here, we summarize recent advances in the use of ionizing rays as a means to induce or potentiate therapeutically relevant anticancer immune responses. In addition, we present clinical trials initiated during the past 12 months to test the actual benefit of radioimmunotherapy in cancer patients.