Irinotecan fluorouracil plus leucovorin is not superior to fluorouracil plus leucovorin alone as adjuvant treatment for stage III colon cancer: results of CALGB 89803

Comparative effectiveness of oxaliplatin vs non-oxaliplatin-containing adjuvant chemotherapy for stage III colon cancer

BACKGROUND

The addition of oxaliplatin to adjuvant 5-fluorouracil (5-FU) improves survival of patients with stage III colon cancer in randomized clinical trials (RCTs). However, RCT participants are younger, healthier, and less racially diverse than the general cancer population. Thus, the benefit of oxaliplatin outside RCTs is uncertain.

SUBJECTS AND METHODS

Patients younger than 75 years with stage III colon cancer who received chemotherapy within 120 days of surgical resection were identified from five observational data sources-the Surveillance, Epidemiology, and End Results registry linked to Medicare claims (SEER-Medicare), the New York State Cancer Registry (NYSCR) linked to Medicaid and Medicare claims, the National Comprehensive Cancer Network (NCCN) Outcomes Database, and the Cancer Care Outcomes Research & Surveillance Consortium (CanCORS). Overall survival (OS) was compared among patients treated with oxaliplatin vs non-oxaliplatin-containing adjuvant chemotherapy. Overall survival for 4060 patients diagnosed during 2004-2009 was compared with pooled data from five RCTs (the Adjuvant Colon Cancer ENdpoinTs [ACCENT] group, n = 8292). Datasets were juxtaposed but not combined using Kaplan-Meier curves. Covariate and propensity score adjusted proportional hazards models were used to calculate adjusted survival hazard ratios (HR). Stratified analyses examined effect modifiers. All statistical tests were two-sided.

RESULTS

The survival advantage associated with the addition of oxaliplatin to adjuvant 5-FU was evident across diverse practice settings (3-year OS: RCTs, 86% [n = 1273]; SEER-Medicare, 80% [n = 1152]; CanCORS, 88% [n = 129]; NYSCR-Medicaid, 82% [n = 54]; NYSCR-Medicare, 79% [n = 180]; and NCCN, 86% [n = 438]). A statistically significant improvement in 3-year overall survival was seen in the largest cohort, SEER-Medicare, and in the NYSCR-Medicare cohort (non-oxaliplatin-containing vs oxaliplatin-containing adjuvant therapy, adjusted HR of death: pooled RCTs: HR = 0.80, 95% CI = 0.70 to 0.92, P = .002; SEER-Medicare: HR = 0.70, 95% CI = 0.60 to 0.82, P < .001; NYSCR-Medicare patients aged ≥65 years: HR = 0.58, 95% CI = 0.38 to 0.90, P = .02). The association between oxaliplatin treatment and better survival was maintained in older and minority group patients, as well as those with higher comorbidity.

CONCLUSION

The addition of oxaliplatin to 5-FU appears to be associated with better survival among patients receiving adjuvant colon cancer treatment in the community.

Predictive and prognostic roles of BRAF mutation in stage III colon cancer: results from intergroup trial CALGB 89803

PURPOSE

Alterations in the RAS-RAF-MAP2K (MEK)-MAPK signaling pathway are major drivers in colorectal carcinogenesis. In colorectal cancer, BRAF mutation is associated with microsatellite instability (MSI), and typically predicts inferior prognosis. We examined the effect of BRAF mutation on survival and treatment efficacy in patients with stage III colon cancer.

METHODS

We assessed status of BRAF c.1799T>A (p.V600E) mutation and MSI in 506 stage III colon cancer patients enrolled in a randomized adjuvant chemotherapy trial [5-fluorouracil and leucovorin (FU/LV) vs. irinotecan (CPT11), FU and LV (IFL); CALGB 89803]. Cox proportional hazards model was used to assess the prognostic role of BRAF mutation, adjusting for clinical features, adjuvant chemotherapy arm, and MSI status.

RESULTS

Compared with 431 BRAF wild-type patients, 75 BRAF-mutated patients experienced significantly worse overall survival [OS; log-rank P = 0.015; multivariate HR = 1.66; 95% CI: 1.05-2.63]. By assessing combined status of BRAF and MSI, it seemed that BRAF-mutated MSS (microsatellite stable) tumor was an unfavorable subtype, whereas BRAF wild-type MSI-high tumor was a favorable subtype, and BRAF-mutated MSI-high tumor and BRAF wild-type MSS tumor were intermediate subtypes. Among patients with BRAF-mutated tumors, a nonsignificant trend toward improved OS was observed for IFL versus FU/LV arm (multivariate HR = 0.52; 95% CI: 0.25-1.10). Among patients with BRAF wild-type cancer, IFL conferred no suggestion of benefit beyond FU/LV alone (multivariate HR = 1.02; 95% CI: 0.72-1.46).

CONCLUSIONS

BRAF mutation is associated with inferior survival in stage III colon cancer. Additional studies are necessary to assess whether there is any predictive role of BRAF mutation for irinotecan-based therapy.

Personalized treatment of colorectal cancer

In the last 15 years, significant progress in the management of colorectal cancer (CRC) has been achieved with several new agents licensed extending median overall survival for stage IV disease to about 2 years. Treatment of CRC is stage-specific, multidisciplinary, and based on patient and tumor characteristics. Although especially early stages (0-III, according to Union for International Cancer Control) are treated with curative intent, patients with limited stage IV disease (liver and/or lung or localized peritoneal metastases) might still be curable in a multimodality approach including surgery, perioperative chemotherapy and/or radiotherapy. Despite the broad variety of prognostic factors, treatment decisions and selection of drugs are mainly based on clinicopathologic variables for early stage CRC, extent of disease, potential resectability, patients' eligibility to receive aggressive treatments including chemotherapy, surgery, and very few molecular markers such as KRAS mutational status for advanced disease. However, a tailored approach for the treatment of CRC taking into account all mentioned factors is currently recommended by national and international guidelines and will be discussed in this review.

Impact of chemotherapy-related prognostic factors on long-term survival in patients with stage III colorectal cancer after curative resection

BACKGROUND

This retrospective study evaluated the prognostic factors of chemotherapy in stage III colorectal cancer after curative resection.

METHODS

From 1996 to 2001, 1,054 patients with primary single colorectal cancer underwent curative resection. Seven hundred sixteen patients received various 5-fluorouracil (FU)-based adjuvant chemotherapy regimens, including oral and intravenous treatments. The chemotherapy-related parameters examined included therapeutic duration, frequency, route of administration, composition of combination therapies, and postoperative time interval from the operation to the start of chemotherapy.

RESULTS

The therapeutic duration and postoperative time interval of starting therapy were independent prognostic factors, in addition to clinicopathological factors. The 8-year cancer-specific/overall survival rates in patients who received chemotherapy for >4 months (63.0/58.6%) were significantly higher than the rates in patients who received no chemotherapy (56.7/37.7%, P < 0.01) and those who remained on chemotherapy for 1-4 months (49.4/41.9%, P < 0.05). The 8-year cancer-specific/overall survival rates in patients who waited 1-5 weeks after surgery to receive chemotherapy (62.9/58.5%) were significantly higher versus rates in those who did not receive chemotherapy (56.7/37.7%) and those who did not receive chemotherapy until >5 weeks after surgery (52.3/45.9%) (both P < 0.05). Survival rates did not differ between patients who did not undergo chemotherapy, those for whom chemotherapy lasted 1-4 months, and patients who did not receive chemotherapy until >5 weeks after surgery.

CONCLUSIONS

The appropriate duration of therapy and early chemotherapy after surgery were 2 of the most important factors in eradicating occult cancer and effecting long-term survival benefits in patients with stage III colorectal cancer.

Is there currently an established role for the use of predictive or prognostic molecular markers in the management of colorectal cancer? A point/counterpoint

The term "personalized oncology" means different things to the oncologist than to the patient. But fundamentally, the phrase creates the expectation that decisions can be informed by the unique features of the patient and patient's cancer. Much like determining antibiotic sensitivities in urinary tract infections, the oncologist is expected to choose the right treatment(s), for each individual patient. Numerous methods can be used to "personalize" management decisions, although truly useful biomarkers continue to escape our grasp. Positron Emission Tomography in patients with GI stromal tumors or genotyping of c-kit in chronic myelogenous leukemia cells can guide the use of imatinib, these scenarios represent a minority of patients. The promise of individualized therapy, however, has led to the commercialization of numerous assays to probe patient's genetic make-up and that of the tumor. Breast cancer management has benefitted from the analysis of gene recurrence scores. More recently the analysis of germline or tumor-associated mutations in non-small cell lung cancer and melanoma has led to clinically meaningful molecular subsets of these diseases, guiding the successful targeting of such cancers with small-molecule inhibitors. Despite the high incidence of colorectal cancer and our relatively long-standing grasp of the molecular pathways in colorectal carcinogenesis, the management of these patients remains mostly empiric and movement toward "personalization" has been slow and incremental. Now, however, molecular imaging and commercial assays for genetic makeup of tumor specimens has put the oncologist and oncologic surgeon in the crossfire with patients and families who believe the era of "personalization" is here.

Comparative analysis of various prognostic nodal factors, adjuvant chemotherapy and survival among stage III colon cancer patients over 65 years: an analysis using surveillance, epidemiology and end results (SEER)-Medicare data

AIM

The prognostic effects of chemotherapy and various lymph node measures [positive nodes, total node count and the positive lymph node ratio (PLNR)] have been established. It is unknown whether the cancer-specific survival benefit of chemotherapy differs across these nodal prognostic categories.

METHOD

This retrospective analysis of linked Surveillance, Epidemiology and End Results (SEER) data and Medicare data (SEER-Medicare)included patients ≥ 65 years of age with a diagnosis of stage III colon cancer between 1997 and 2002. We grouped patients according to the number of positive nodes (N1 and N2), total node count (≥ 12 and < 12 total nodes) and PLNR (below the 75th percentile and at least at the 75th percentile of the PLNR). The end point was colon cancer-specific mortality.

RESULTS

Fifty-one per cent (3701) of the 7263 patients received adjuvant therapy during the time period 1997-2002. The mean (standard deviation) number of total nodes examined was 13 (9) and the number of positive nodes identified was 3 (3). Patients with N2 disease, < 12 total nodes examined and a high PLNR had a worse survival at 2, 3 and 5 years following colectomy. Utilization of chemotherapy demonstrated a colon cancer-specific survival benefit (hazard ratio at median follow up = 0.7; P < 0.001) that was consistent and statistically significant across the three nodal prognostic categories examined.

CONCLUSION

The benefit of chemotherapy did not vary based on N stage, total node count or PLNR. The results favour a broad-based approach towards increasing the chemotherapy treatment rates in stage III patients of ≥ 65 years of age, rather than an approach that targets clinical subgroups.

Curative-Intent Treatment for Colorectal Liver Metastases: A Medical Oncologist's Perspective

Resection or ablation of CRC liver metastases can be offered with curative intent in some, but not all patients in whom resection is technically possible. Chemotherapy can improve the potential for cure to some degree, either in the adjuvant or neoadjuvant setting, or, in relatively rare circumstances, by converting truly unresectable disease into resectable. Careful and realistic patient selection, with an individualized and realistic assessment of curative potential, is key to providing each patient with the means to make realistic treatment choices.

Chemotherapy-induced diarrhea: pathophysiology, frequency and guideline-based management

Diarrhea is one of the main drawbacks for cancer patients. Possible etiologies could be radiotherapy, chemotherapeutic agents, decreased physical performance, graft versus host disease and infections. Chemotherapy-induced diarrhea (CID) is a common problem, especially in patients with advanced cancer. The incidence of CID has been reported to be as high as 50-80% of treated patients (≥30% CTC grade 3-5), especially with 5-fluorouracil bolus or some combination therapies of irinotecan and fluoropyrimidines (IFL, XELIRI). Regardless of the molecular targeted approach of tyrosine kinase inhibitors and antibodies, diarrhea is a common side effect in up to 60% of patients with up to 10% having severe diarrhea. Furthermore, the underlying pathophysiology is still under investigation. Despite the number of clinical trials evaluating therapeutic or prophylactic measures in CID, there are just three drugs recommended in current guidelines: loperamide, deodorized tincture of opium and octreotide. Newer strategies and more effective agents are being developed to reduce the morbidity and mortality associated with CID. Recent research focusing on the prophylactic use of antibiotics, budesonide, probiotics or activated charcoal still have to define the role of these drugs in the routine clinical setting. Whereas therapeutic management and clinical work-up of patients presenting with diarrhea after chemotherapy are rather well defined, prediction and prevention of CID is an evolving field. Current research focuses on establishing predictive factors for CID like uridine diphosphate glucuronosyltransferase-1A1 polymorphisms for irinotecan or dihydropyrimidine-dehydrogenase insufficiency for fluoropyrimidines.

Relationship between statin use and colon cancer recurrence and survival: results from CALGB 89803

BACKGROUND

Although preclinical and epidemiological data suggest that statins may have antineoplastic properties, the impact of statin use on patient survival after a curative resection of stage III colon cancer is unknown.

METHODS

We conducted a prospective observational study of 842 patients with stage III colon cancer enrolled in a randomized adjuvant chemotherapy trial from April 1999 to May 2001 to investigate the relationship between statin use and survival. Disease-free survival (DFS), recurrence-free survival (RFS), and overall survival (OS) were investigated by Kaplan-Meier curves and log-rank tests in the overall study population and in a subset of patients stratified by KRAS mutation status (n = 394), and Cox proportional hazards regression was used to assess the simultaneous impact of confounding variables. All statistical tests were two-sided.

RESULTS

Among 842 patients, 134 (15.9%) reported statin use after completing adjuvant chemotherapy. DFS among statin users and nonusers was similar (hazard ratio [HR] of cancer recurrence or death = 1.04, 95% confidence interval [CI] = 0.73 to 1.49). RFS and OS were also similar between statin users and nonusers (adjusted HR of cancer recurrence = 1.14, 95% CI = 0.77 to 1.69; adjusted HR of death = 1.15, 95% CI = 0.77 to 1.71). Survival outcomes were similar regardless of increasing duration of statin use before cancer diagnosis (P(trend) = .63, .63, and .59 for DFS, RFS, and OS, respectively). The impact of statin use did not differ by tumor KRAS mutation status, with similar DFS, RFS, and OS for statin use among mutant and wild-type subgroups (P(interaction) = .84, .67, and .98 for DFS, RFS, and OS, respectively).

CONCLUSION

Statin use during and after adjuvant chemotherapy was not associated with improved DFS, RFS, or OS in patients with stage III colon cancer, regardless of KRAS mutation status.

Outcomes among black patients with stage II and III colon cancer receiving chemotherapy: an analysis of ACCENT adjuvant trials

BACKGROUND

Among patients with resected colon cancer, black patients have worse survival than whites. We investigated whether disparities in survival and related endpoints would persist when patients were treated with identical therapies in controlled clinical trials.

METHODS

We assessed 14,611 patients (1218 black and 13,393 white) who received standardized adjuvant treatment in 12 randomized controlled clinical trials conducted in North America for resected stage II and stage III colon cancer between 1977 and 2002. Individual patient data on covariates and outcomes were extracted from the Adjuvant Colon Cancer ENdpoinTs (ACCENT) database. The endpoints examined in this meta-analysis were overall survival (time to death), recurrence-free survival (time to recurrence or death), and recurrence-free interval (time to recurrence). Cox models were stratified by study and controlled for sex, stage, age, and treatment to determine the effect of race. Kaplan-Meier estimates were adjusted for similar covariates to control for confounding. All statistical tests were two-sided.

RESULTS

Black patients were younger than whites (median age, 58 vs 61 years, respectively; P < .001) and more likely to be female (55% vs 45%, respectively; P < .001). Overall survival was worse in black patients than whites (hazard ratio [HR] of death = 1.22, 95% confidence interval [CI] = 1.11 to 1.34, P < .001). Five-year overall survival rates for blacks and whites were 68.2% and 72.8%, respectively. When subsets defined by sex, stage, and age were analyzed, overall survival was consistently worse in black patients. Recurrence-free survival was worse in black patients than whites (HR of recurrence or death = 1.14, 95% CI = 1.04 to 1.24, P = .0045). Three-year recurrence-free survival rates in blacks and whites were 68.4% and 72.1%, respectively. In contrast, recurrence-free interval was similar in black and white patients (HR of recurrence = 1.08, 95% CI = 0.97 to 1.19, P = .15). Three-year recurrence-free interval rates in blacks and whites were 71.3% and 74.2%, respectively.

CONCLUSIONS

Black patients with resected stage II and stage III colon cancer who were treated with the same therapy as white patients experienced worse overall and recurrence-free survival, but similar recurrence-free interval, compared with white patients. The differences in survival may be mostly because of factors unrelated to the patients' adjuvant colon cancer treatment.

Long-term survival benefits of adjuvant chemotherapy by decreasing incidence of tumor recurrence without delaying relapse in stage III colorectal cancer

BACKGROUNDS AND AIMS

To elucidate the survival benefits of adjuvant chemotherapy by decreasing incidence or by delaying time of tumor recurrence, we reported the long-term results of a nonrandomized prospective study comparing the adjuvant chemotherapy to no chemotherapy in stage III colorectal cancer.

PATIENTS

From 1991 to 1995, 463 patients with stage III colorectal cancer were divided to three groups which were no chemotherapy, weekly chemotherapy, and monthly chemotherapy (5-FU plus levamisole).

RESULTS

The recurrent incidence was significantly decreased in patients with chemotherapy (47.8% vs. 63.9% of no chemotherapy, P = 0.001), resulting into better survival. The 10-year cancer-specific and overall survival rates of patients with chemotherapy vs. no chemotherapy were 52.1% vs. 37.8% and 46.9% vs. 29.9%, respectively (P < 0.001). Weekly chemotherapy had better survival than monthly chemotherapy (P < 0.05). There was no significant difference in recurrent time or types between the patients with and without chemotherapy. The percentages of patients with recurrence happened within 3 years were 85.2% and 84.6% of those with and without chemotherapy, respectively. Patients with advanced stage of T4b invasion depth, N2, and central node invasion had no significant survival benefits by adjuvant chemotherapy.

CONCLUSIONS

Long-term survival benefits achieved by adjuvant chemotherapy is through decreasing recurrent incidence, not through postponing tumor recurrent time. That means adjuvant chemotherapy indeed cures some patients by eradicating occult tumor. In adjuvant setting, more powerful regimen for eradicating occult tumor is the keystone to improve long-term survival of stage III colorectal cancer.

From chemotherapy to targeted therapy in adjuvant treatment for stage III colon cancer

Colorectal cancer represents a major public health problem due to its frequency and mortality rate. Adjuvant chemotherapy has improved the prognosis of colon cancer. Six months of oxaliplatin and fluoropyrimidine in combination is the standard adjuvant treatment in stage III patients. Ongoing trials are evaluating the optimal duration of chemotherapy. A critical issue, which needs to be specifically addressed, is the role of adjuvant therapy in elderly patients. Preliminary results of trials evaluating targeted therapies in combination with chemotherapy have shown disappointing results. The monoclonal antibodies bevacizumab, targeting vascular endothelial growth factor (VEGF) and cetuximab, targeting epidermal growth factor receptor (EGFR)/HER1, which improved survival in patients with metastatic colorectal cancer, could even induce chemotherapy resistance in a significant number of patients in the adjuvant setting. A major challenge is emerging to understand the mechanism leading to this effect and to multi-target the tumor cell proliferation and survival network. Clarity regarding the clinical signal needed before launching a phase III study and optimized designs adapted to multiple agents are urgently needed for new trials.

Curable metastatic colorectal cancer

In the United States and Europe, colorectal cancer (CRC) is the third most common malignancy and the second leading cause of cancer-related death for men and women. In the course of their disease, many patients will present with metastasis, with the liver and lung being the most common locations. Untreated metastatic disease carries a poor prognosis. However, cure is still possible for selected patients with stage IV CRC. Surgical resection provides the best chance for cure, and chemotherapy can be a valuable adjunct when given in a (neo-)adjuvant fashion or as conversion therapy to downsize initially unresectable tumors. For unresectable metastases, alternative treatment options include radiofrequency ablation and hepatic artery infusion. Additional local therapies are being explored, including chemoembolization, radioembolization, and stereotactic body radiation therapy. Prospective randomized trials are needed to further clarify the roles of these novel treatment options in the clinician's repertoire for metastatic CRC.

Biotherapy in the Adjuvant Treatment of Colorectal Cancer

The use of adjuvant chemotherapy has improved survival in early-stage colon cancer. Ongoing adjuvant clinical trials are evaluating the addition of targeted therapies to standard chemotherapy regimen. Preliminary results with bevacizumab were disappointing. Also, cetuximab added to chemotherapy does not seem to be better than chemotherapy alone, even in selected wild-type KRAS populations. A better understanding of mechanisms of action of drugs, tumor biology, and predictive biomarkers are needed to design future adjuvant trials.

Productivity savings from colorectal cancer prevention and control strategies

BACKGROUND

Lost productivity represents a considerable portion of the total economic burden of colorectal cancer (CRC), but cost-effectiveness studies of CRC prevention and control have not included these costs and therefore underestimate potential savings from CRC prevention and control.

PURPOSE

To use microsimulation modeling study to estimate and project productivity costs of CRC and to model the savings from four approaches to reducing CRC incidence and mortality: risk factor reduction, improved screening, improved treatment, and a simultaneous approach where all three strategies are implemented.

METHODS

A model was developed to project productivity losses from CRC using the U.S. population with CRC incidence and mortality projected through the year 2020. Outcome measures were CRC mortality, morbidity, and productivity savings.

RESULTS

With 2005 levels in risk factors, screening, and treatment, 48,748 CRC deaths occurred in 2010, amounting to $21 billion of lost productivity. Using prevention and treatment strategies simultaneously, 3586 deaths could have been avoided in 2010, leading to a savings of $1.4 billion. Cumulatively, by 2020, simultaneous strategies that reduce risk factors and increase screening and treatment could result in 101,353 deaths avoided and $33.9 billion in savings in reduced productivity loss. Improved screening rates alone led to nearly $14.7 billion in savings between 2005 and 2020, followed by risk factor reduction ($12.4 billion) and improved treatment ($8.4 billion).

CONCLUSIONS

The savings in productivity loss from strategies to reduce CRC incidence and mortality are substantial, providing evidence that CRC prevention and control strategies are likely to be cost-saving.

Longitudinal patterns of chemotherapy use in metastatic colorectal cancer

Multiple agents and combination therapies available to patients with advanced colorectal cancer have significantly improved survival and provided an opportunity for individualization of care, allowing clinicians and patients to prioritize risks and benefits of comparable regimens.

Microsatellite instability and loss of heterozygosity at chromosomal location 18q: prospective evaluation of biomarkers for stages II and III colon cancer--a study of CALGB 9581 and 89803

PURPOSE

Colorectal cancer (CRC) develops as a result of a series of accumulated genomic changes that produce oncogene activation and tumor suppressor gene loss. These characteristics may classify CRC into subsets of distinct clinical behaviors.

PATIENTS AND METHODS

We studied two of these genomic defects-mismatch repair deficiency (MMR-D) and loss of heterozygosity at chromosomal location 18q (18qLOH)-in patients enrolled onto two phase III cooperative group trials for treatment of potentially curable colon cancer. These trials included prospective secondary analyses to determine the relationship between these markers and treatment outcome. A total of 1,852 patients were tested for MMR status and 955 (excluding patients with MMR-D tumors) for 18qLOH.

RESULTS

Compared with stage III, more stage II tumors were MMR-D (21.3% v 14.4%; P < .001) and were intact at 18q (24.2% v 15.1%; P = .001). For the combined cohort, patients with MMR-D tumors had better 5-year disease-free survival (DFS; 0.76 v 0.67; P < .001) and overall survival (OS; 0.81 v 0.78; P = .029) than those with MMR intact (MMR-I) tumors. Among patients with MMR-I tumors, the status of 18q did not affect outcome, with 5-year values for patients with 18q intact versus 18qLOH tumors of 0.74 versus 0.65 (P = .18) for DFS and 0.81 versus 0.77 (P = .18) for OS.

CONCLUSION

We conclude that MMR-D tumor status, but not the presence of 18qLOH, has prognostic value for stages II and III colon cancer.

Microsatellite instability in the management of colorectal cancer

Microsatellite instability (MSI) is a form of genetic instability caused by alterations in the DNA mismatch repair system. Approximately 15% of colorectal cancers display MSI due to a germline mutation in one of the mismatch repair genes (MLH1, MSH2, MSH6 and PMS2) or to epigenetic silencing of MLH1. Colorectal cancers with MSI have distinctive features, including a tendency to arise in the proximal colon, poor differentiation, lymphocytic infiltration and mucinous or signet-ring histology. Patients with MSI tumors appear to have a better prognosis than those with microsatellite stable tumors, but curiously the responses to 5-fluorouracil-based chemotherapy regimens are poorer with MSI tumors. Preliminary data suggest possible advantages of irinotecan-based regimens, but these findings need validation in well-designed clinical trials.

Targeting angiogenesis in esophagogastric adenocarcinoma

The possibility of targeting tumor angiogenesis was postulated almost 40 years ago. The vascular endothelial growth factor (VEGF) family and its receptors have since been characterized and extensively studied. VEGF overexpression is a common finding in solid tumors, including esophagogastric cancer, and frequently correlates with poor prognosis. Monoclonal antibodies, soluble receptors, and small-molecule tyrosine kinase inhibitors have been developed to inhibit tumor angiogenesis, and antiangiogenic therapy is now a component of standard treatment for advanced renal cell, hepatocellular, colorectal, breast, and non-small cell lung carcinomas. The small-molecule tyrosine kinase inhibitors sunitinib and sorafenib have been evaluated in phase II studies in esophagogastric cancer but appear to have only modest activity. Similarly, despite promising efficacy signals from phase II studies, the addition of the anti-VEGF-A monoclonal antibody bevacizumab to cisplatin plus capecitabine failed to result in a longer overall survival duration than with the chemotherapy doublet plus placebo. The response rate and progression-free survival interval were significantly greater with bevacizumab, confirming some efficacy in advanced gastric cancer, but with inadequate benefit to justify the high cost of treatment. Evaluation of bevacizumab in the neoadjuvant and perioperative settings continues, hypothesizing that a higher response rate will translate into longer survival in patients with operable disease. Despite extensive research, the discovery of a reliable predictive biomarker for antiangiogenic therapy continues to elude the scientific and oncology communities, and mechanisms of primary and acquired resistance are incompletely understood. We are therefore currently unable to personalize antiangiogenic therapy for established indications, or use molecular selection for clinical trials evaluating novel indications.

Targeting angiogenesis in esophagogastric adenocarcinoma

The possibility of targeting tumor angiogenesis was postulated almost 40 years ago. The vascular endothelial growth factor (VEGF) family and its receptors have since been characterized and extensively studied. VEGF overexpression is a common finding in solid tumors, including esophagogastric cancer, and frequently correlates with poor prognosis. Monoclonal antibodies, soluble receptors, and small-molecule tyrosine kinase inhibitors have been developed to inhibit tumor angiogenesis, and antiangiogenic therapy is now a component of standard treatment for advanced renal cell, hepatocellular, colorectal, breast, and non-small cell lung carcinomas. The small-molecule tyrosine kinase inhibitors sunitinib and sorafenib have been evaluated in phase II studies in esophagogastric cancer but appear to have only modest activity. Similarly, despite promising efficacy signals from phase II studies, the addition of the anti-VEGF-A monoclonal antibody bevacizumab to cisplatin plus capecitabine failed to result in a longer overall survival duration than with the chemotherapy doublet plus placebo. The response rate and progression-free survival interval were significantly greater with bevacizumab, confirming some efficacy in advanced gastric cancer, but with inadequate benefit to justify the high cost of treatment. Evaluation of bevacizumab in the neoadjuvant and perioperative settings continues, hypothesizing that a higher response rate will translate into longer survival in patients with operable disease. Despite extensive research, the discovery of a reliable predictive biomarker for antiangiogenic therapy continues to elude the scientific and oncology communities, and mechanisms of primary and acquired resistance are incompletely understood. We are therefore currently unable to personalize antiangiogenic therapy for established indications, or use molecular selection for clinical trials evaluating novel indications.

Personalized colon cancer care in 2010

Colon cancer (CC) therapies have improved patient outcomes significantly over the last decades in both the adjuvant and metastatic settings. With the introduction of a number of novel agents, both traditional chemotherapies and biologically targeted agents, the need to identify subgroups that are likely and not likely to respond to a particular treatment regimen is paramount. This will allow patients who are likely to benefit to receive optimal care, while sparing those unlikely to benefit from unnecessary toxicity and cost. With the identification of several novel biomarkers and a variety of technologies to interrogate the genome, we already are able to rapidly study patient tumor or blood samples and normal tissues to generate a large dataset of aberrations within the cancer. How to digest this complex information to obtain accurate, reliable, and meaningful results that will allow us to provide truly personalized care for CC patients is just starting to be addressed. In this article, we briefly review the history of CC treatment, with an emphasis on current clinical standards that incorporate a "personalized medicine" approach. We then review strategies that will potentially improve our ability to individualize therapy in the future.

Targeted therapies as adjuvant treatment for early-stage colorectal cancer: first impressions and clinical questions

The use of adjuvant chemotherapy has improved survival in early-stage colon cancer. Ongoing adjuvant clinical trials are evaluating the addition of targeted therapies to standard chemotherapy regimen. Preliminary results with bevacizumab were disappointing. Also, cetuximab added to chemotherapy does not seem to be better than chemotherapy alone, even in selected wild-type KRAS populations. A better understanding of mechanisms of action of drugs, tumor biology, and predictive biomarkers are needed to design future adjuvant trials.

Prognostic value of colorectal cancer biomarkers

Despite the large amount of data in cancer biology and many studies into the likely survival of colorectal cancer (CRC) patients, knowledge regarding the issue of CRC prognostic biomarkers remains poor. The Tumor-Node-Metastasis (TNM) staging system continues to be the most powerful and reliable predictor of the clinical outcome of CRC patients. The exponential increase of knowledge in the field of molecular genetics has lead to the identification of specific alterations involved in the malignant progression. Many of these genetic alterations were proposed as biomarkers which could be used in clinical practice to estimate CRC prognosis. Recently there has been an explosive increase in the number of putative biomarkers able to predict the response to specific adjuvant treatment. In this review we explore and summarize data concerning prognostic and predictive biomarkers and we attempt to shed light on recent research that could lead to the emergence of new biomarkers in CRC.

Microsatellite instability in colorectal cancer: from molecular oncogenic mechanisms to clinical implications

BACKGROUND

Microsatellite instability (MSI) constitutes an important oncogenic molecular pathway in colorectal cancer (CRC), representing approximately 15% of all colorectal malignant tumours. In roughly one third of the cases, the underlying DNA mismatch repair (MMR) defect is inherited through the transmission of a mutation in one of the genes involved in MMR, predominantly MSH2 and MLH1, or less frequently, MSH6 or PMS2. In the overwhelming number of sporadic cases, MSI results from epigenetic MLH1 silencing through hypermethylation of its promoter. MMR deficiency promotes colorectal oncogenesis through the accumulation of numerous mutations in crucial target genes harbouring mononucleotide repeats, notably in those involved in the control of cell proliferation and differentiation, as well as DNA damage signalling and repair.

DESIGN

In this review, we describe the molecular aspects of the MMR system and the biological consequences of its defect on the oncogenic process, and we discuss the various experimental systems used to evaluate the efficacy of cytotoxic drugs on MSI colorectal cells lines. There is increasing evidence showing that MSI CRCs differ from all CRCs in terms of prognosis and response to the treatment. We report the clinical studies that have evaluated the prognostic and predictive value of MSI status on clinical outcome in patients treated with various chemotherapy regimens used in the adjuvant setting or for advanced CRCs.

CONCLUSION

In view of this, the opportunity of a systematic MSI phenotyping in the clinical management of patients with CRC is further discussed.

Adjuvant systemic chemotherapy for Stage II and III colon cancer after complete resection: an updated practice guideline

AIMS

The standard adjuvant therapy for resected stage III colon cancer has been intravenous 5-fluorouracil. However, newer chemotherapy agents, such as capecitabine, oxaliplatin and irinotecan, have been investigated in clinical trials since the publication of the original guidelines. The Gastrointestinal Cancer Disease Site Group (DSG) conducted a systematic review of the evidence for the use of adjuvant systemic chemotherapy for patients with resected stage II and III colon cancer and developed an updated practice guideline based on that evidence and expert consensus. The following research questions were addressed: Should patients with stage II or III colon cancer receive adjuvant systemic chemotherapy? What are the preferred adjuvant systemic chemotherapy options for patients with completely resected stage II or III colon cancer? Outcomes of interest were disease-free survival, overall survival, adverse effects and quality of life.

MATERIALS AND METHODS

A systematic search of published studies was conducted for the time period following the publication of the original guidelines to identify relevant randomised trials and syntheses of evidence in the form of meta-analyses. Recommendations were based on that evidence, evidence contained in the original guidelines and consensus of the Gastrointestinal Cancer DSG. The systematic review and practice guideline were externally reviewed through a mailed survey of practitioners in Ontario, Canada.

RESULTS

Recommendations were drafted based on the available evidence and expert consensus.

CONCLUSIONS

The routine use of adjuvant chemotherapy for all patients with stage II colon cancer is not recommended. However, a subset of patients with high-risk stage II disease should be considered for adjuvant therapy. Patients with completely resected stage III colon cancer should be offered adjuvant chemotherapy. Treatment should depend on factors such as patient suitability and preference, and patients and clinicians must work together to determine the optimal course of treatment.

A randomized phase III trial of adjuvant chemotherapy with irinotecan, leucovorin and fluorouracil versus leucovorin and fluorouracil for stage II and III colon cancer: a Hellenic Cooperative Oncology Group study

BACKGROUND

Colon cancer is a public health problem worldwide. Adjuvant chemotherapy after surgical resection for stage III colon cancer has been shown to improve both progression-free and overall survival, and is currently recommended as standard therapy. However, its value for patients with stage II disease remains controversial. When this study was designed 5-fluorouracil (5FU) plus leucovorin (LV) was standard adjuvant treatment for colon cancer. Irinotecan (CPT-11) is a topoisomerase I inhibitor with activity in metastatic disease. In this multicenter adjuvant phase III trial, we evaluated the addition of irinotecan to weekly 5FU plus LV in patients with stage II or III colon cancer.

METHODS

The study included 873 eligible patients. The treatment consisted of weekly administration of irinotecan 80 mg/m2 intravenously (i.v.), LV 200 mg/m2 and 5FU 450 mg/m2 bolus (Arm A) versus LV 200 mg/m2 and 5FU 500 mg/m2 i.v. bolus (Arm B). In Arm A, treatments were administered weekly for four consecutive weeks, followed by a two-week rest, for a total of six cycles, while in Arm B treatments were administered weekly for six consecutive weeks, followed by a two-week rest, for a total of four cycles. The primary end-point was disease-free survival (DFS) at three years.

RESULTS

The probability of overall survival (OS) at three years was 0.88 for patients in Arm A and 0.86 for those in Arm B, while the five-year OS probability was 0.78 and 0.76 for patients in Arm A and Arm B, respectively (P = 0.436). Furthermore, the probability of DFS at three years was 0.78 and 0.76 for patients in Arm A and Arm B, respectively (P = 0.334). With the exception of leucopenia and neutropenia, which were higher in patients in Arm A, there were no significant differences in Grades 3 and 4 toxicities between the two regimens. The most frequently recorded Grade 3/4 toxicity was diarrhea in both treatment arms.

CONCLUSIONS

Irinotecan added to weekly bolus 5FU plus LV did not result in improvement in disease-free or overall survival in stage II or III colon cancer, but did increase toxicity.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry: ACTRN12610000148077.

Chemoradiation for rectal cancer: rationale, approaches, and controversies

The standard adjuvant treatment of cT3 and/or N+ rectal cancer is preoperative chemoradiation. However, there are many controversies regarding this approach. These controversies include the role of short course radiation, whether postoperative adjuvant chemotherapy is necessary for all patients, and if the type of surgery following chemoradiation should be based on the response rate. More accurate imaging techniques and/or molecular markers may help identify patients with positive pelvic nodes to reduce the chance of overtreatment with preoperative therapy. Will more effective systemic agents both improve the results of radiation, as well as modify the need for pelvic radiation? These questions and others remain active areas of clinical investigation.

Two or three year disease-free survival (DFS) as a primary end-point in stage III adjuvant colon cancer trials with fluoropyrimidines with or without oxaliplatin or irinotecan: data from 12,676 patients from MOSAIC, X-ACT, PETACC-3, C-06, C-07 and C89803

BACKGROUND

The ACCENT group previously established disease-free survival (DFS) with 2 or 3 years median follow-up to predict 5 year overall survival (5 year OS) in stage II and III colon cancer. ACCENT further proposed (1) a stronger association between DFS and OS in stage III than II, and (2) 6 or 7 years necessary to demonstrate DFS/OS surrogacy in recent trials. The relationship between end-points in trials with oral fluoropyrimidines, oxaliplatin and irinotecan is unknown.

METHODS

Associations between the treatment effect hazard ratios (HRs) on 2 and 3 years DFS, and 5 and 6 years OS were examined in 6 phase III trials not included in prior analyses from 1997 to 2002. Individual data for 12,676 patients were analysed; two trials each tested oxaliplatin, irinotecan and oral treatment versus 5-FU/LV.

FINDINGS

Overall association between 2/3 year DFS and 5/6 year OS HRs was modest to poor (simple R² measures: 0.58-0.76, model-based R²: 0.17-0.49). In stage III patients, the association increased (model-based R² ≥ 0.79). Observed treatment effects on 2 year DFS accurately 5/6 year OS effects overall and in stage III patients.

INTERPRETATION

In recent trials of cytotoxic chemotherapy, 2 or 3 years DFS HRs are highly predictive of 5 and 6 years OS HRs in stage III but not stage II patients. In all patients the DFS/OS association is stronger for 6 year OS, thus at least 6 year follow-up is recommended to assess OS benefit. These data support DFS as the primary end-point for stage III colon cancer trials testing cytotoxic agents.

Balancing the efficacy and toxicity of chemotherapy in colorectal cancer

As the therapeutic options for the treatment of colorectal cancer have expanded over the past 20 years, so has the complexity of decision making. The goals of treatment in the palliative, adjuvant and neoadjuvant settings vary and it is not only the efficacy of drugs that influence treatment decisions. Age, performance status, the presence of significant comorbidities and the different treatment regimens and strategies provide medical oncologists with an array of options to attempt to maximize patients' quality of life and longevity.

Adjuvant colon cancer chemotherapy: where we are and where we'll go

Many patients with early-stage colon cancer are cured with surgery alone, even if the standard of care remains an uniform approach to adjuvant chemotherapy based primarily on tumour stage. Consequently, it is important to individualize decision-making in this subset of patients with the aim to identify potential prognostic and predictive markers in colon cancer. While 5-fluorouracil, leucovorin, and oxaliplatin are widely known as gold treatment in the post-operative of stage III, well-validated molecular markers might help define which patients with stage II disease are likely to benefit from adjuvant therapy as well. Herein we review the use of adjuvant chemotherapy in colon cancer and analyzed the date on the clinical development of molecular markers to individualize another therapeutic approach in colon cancer.

Optimizing collection of adverse event data in cancer clinical trials supporting supplemental indications

PURPOSE

Although much is known about the safety of an anticancer agent at the time of initial marketing approval, sponsors customarily collect comprehensive safety data for studies that support supplemental indications. This adds significant cost and complexity to the study but may not provide useful new information. The main purpose of this analysis was to assess the amount of safety and concomitant medication data collected to determine a more optimal approach in the collection of these data when used in support of supplemental applications.

METHODS

Following a prospectively developed statistical analysis plan, we reanalyzed safety data from eight previously completed prospective randomized trials.

RESULTS

A total of 107,884 adverse events and 136,608 concomitant medication records were reviewed for the analysis. Of these, four grade 1 to 2 and nine grade 3 and higher events were identified as drug effects that were not included in the previously established safety profiles and could potentially have been missed using subsampling. These events were frequently detected in subsamples of 400 patients or larger. Furthermore, none of the concomitant medication records contributed to labeling changes for the supplemental indications.

CONCLUSION

Our study found that applying the optimized methodologic approach, described herein, has a high probability of detecting new drug safety signals. Focusing data collection on signals that cause physicians to modify or discontinue treatment ensures that safety issues of the highest concern for patients and regulators are captured and has significant potential to relieve strain on the clinical trials system.

Stage II and stage III colon cancer: treatment advances and future directions

Because of its frequency and mortality rate, colorectal cancer represents a major public health problem. Adjuvant chemotherapy has improved the prognosis. Six months of oxaliplatin and fluoropyrimidine in combination is the standard adjuvant treatment in stage III patients. Two monoclonal antibodies, bevacizumab targeting vascular endothelial growth factor and cetuximab targeting epidermal growth factor receptor 1, are being assessed in addition to chemotherapy in the adjuvant setting. Preliminary results of 2 trials have shown disappointing results. Duration of therapy is another other critical issue for the future. Adjuvant chemotherapy in patients with stage II colon cancer is still a subject of controversy. The potential biomarkers that can accurately select patients with stage II or III cancer who are at risk for recurrence to individualize therapy from microsatellite instability to gene signature are reviewed. Adjuvant therapy in elderly patients is another matter of debate due to the lack of survival advantage in the recent trials.

Combined modality therapy for rectal cancer

The standard adjuvant treatment for cT3 and/or N+ rectal cancer is preoperative chemoradiation. However, there are many controversies regarding this approach. These include the role of short course radiation, whether postoperative adjuvant chemotherapy necessary for all patients and whether the type of surgery after chemoradiation should be based on the response rate. More accurate imaging techniques and/or molecular markers may help identify patients with positive pelvic nodes to reduce the chance of overtreatment with preoperative therapy. Will more effective systemic agents both improve the results of radiation as well as modify the need for pelvic radiation? These questions and others remain active areas of clinical investigation.

Multivitamin use is not associated with cancer recurrence or survival in patients with stage III colon cancer: findings from CALGB 89803

PURPOSE

Multivitamin use is widespread in the United States, especially among patients with cancer. However, the influence of multivitamin supplementation on cancer recurrence and death after a curative resection of colon cancer is unknown.

PATIENTS AND METHODS

We conducted a prospective, observational study of 1,038 patients with stage III colon cancer enrolled in a randomized adjuvant chemotherapy trial. Patients reported on multivitamin use during and 6 months after adjuvant chemotherapy. Patients were observed until March 2009 for disease recurrence and death. To minimize bias by occult recurrence, we excluded patients who recurred or died within 90 days of their multivitamin assessment.

RESULTS

Among 1,038 patients, 518 (49.9%) reported multivitamin use during adjuvant chemotherapy. Compared with nonusers, the multivariate hazard ratio (HR) for disease-free survival was 0.94 (95% CI, 0.77 to 1.15) for patients who used multivitamins. Similarly, multivitamin use during adjuvant chemotherapy was not significantly associated with recurrence-free survival (multivariate HR, 0.93; 95% CI, 0.75 to 1.15) or overall survival (multivariate HR 0.92; 95% CI, 0.74 to 1.16). Multivitamin use reported 6 months after completion of adjuvant chemotherapy was also not associated with improved patient outcome, and consistent use both during and following adjuvant therapy conferred no benefit. Neither an increasing number of tablets nor increasing duration of use before cancer diagnosis was associated with cancer recurrence or mortality. Multivitamin use also did not improve the rates of grade 3 and higher GI toxicity.

CONCLUSION

Multivitamin use during and after adjuvant chemotherapy was not significantly associated with improved outcomes in patients with stage III colon cancer.

The role of chemotherapy in managing patients with resectable liver metastases

Colorectal cancer metastatic to the liver is a common oncologic problem, and carefully selected patients can be successfully treated with surgical resection of liver metastases. Perioperative chemotherapy has been shown to increase progression-free survival in patients with resectable liver metastases and can currently be considered a standard therapy for eligible patients. Preoperative chemotherapy can downstage unresectable liver metastases and allow a complete resection. More aggressive chemotherapy as well has the incorporation of targeted agents such as cetuximab and bevacizumab into modern chemotherapy regimens has resulted in higher response rates, which may translate into improved survival. Preoperative chemotherapy can increase postoperative complications after hepatic resection, and the decision to use such therapy should be made in a multidisciplinary setting.