Oxaliplatin as adjuvant therapy for colon cancer: updated results of NSABP C-07 trial, including survival and subset analyses

Safety and effectiveness of oxaliplatin-based chemotherapy regimens in adults 75 years and older with colorectal cancer

Although the safety and efficacy of oxaliplatin-based chemotherapy regimens for colorectal cancer (CRC) have been demonstrated in adults > 75 years of age enrolled in clinical trials, safety and effectiveness outside the trial setting are less established. In this comparative effectiveness study, we note that older adults with stage III and metastatic CRC treated outside of a clinical trial experienced safety and effectiveness of oxaliplatin-based chemotherapy regimens comparable to that of younger adults.

BACKGROUND

Although the safety and efficacy of oxaliplatin-based chemotherapy regimens for colorectal cancer (CRC) have been demonstrated in adults ≥ 75 years of age who are enrolled in clinical trials, safety and effectiveness outside the trial setting are less established.

METHODS

We retrospectively collected cases of patients ≥ 75 years of age who were diagnosed with stage III and metastatic CRC and initiated treatment between January 2000 and January 2007 at 2 academic hospitals in Boston, MA. Cases were matched in a 1:2 ratio to controls who were < 75 years of age by hospital site, stage of disease (stage III vs. metastatic) and line of therapy (first- or second-line or beyond). The primary study endpoints were grade ≥ 3 treatment-associated toxicities and intolerance (number of dose delays/reductions and hospital/facility admissions during treatment). The secondary endpoint was overall survival.

RESULTS

We identified 84 patients ≥ 75 years of age (25% ≥ 80 years) and 168 controls. In the cohort, 77% had colon cancer, 75% had metastatic disease, and 60% were receiving oxaliplatin as first-line therapy. There was no significant difference in grade ≥ 3 treatment-associated toxicities between the patients and the controls (71.4% vs. 68.5%, respectively; P = .63). Further there was no statistically significant difference between patients and controls for combined endpoints of any grade ≥ 3 toxicity or hospital/facility admission (P = .92). With a median follow-up of 52 months, 2-year overall survival was similar between patients and controls (43% vs. 52%, respectively; P = .87).

CONCLUSION

Older adults with stage III and metastatic CRC treated outside of a clinical trial experienced safety and effectiveness of oxaliplatin-based chemotherapy regimens that was comparable to that of younger adults.

Comparative clinical benefits of systemic adjuvant therapy for paradigm solid tumors

Adjuvant therapy employing cytotoxic chemotherapy, molecularly targeted agents, immunologic, and hormonal agents has shown a significant impact upon a variety of solid tumors. The principles that guide adjuvant therapy differ among various tumor types and specific modalities, but generally indicate a greater impact of therapy in the postsurgical setting of micrometastatic disease, for which adjuvant therapy is commonly pursued, vs. the setting of gross unresectable disease. This review of adjuvant therapies in current use for five major solid tumors highlights the rationale for current effective adjuvant therapy, and draws comparisons between the adjuvant regimens that have found application in solid tumors.

Managing choices for older patients with colon cancer: adjuvant therapy

Colon cancer is among the most common cancers in the United States, and the median age of patients at diagnosis is 70. Medical oncologists are commonly asked to comprehensively evaluate elderly patients to estimate individual risk/benefit ratios for adjuvant treatment. Although 40% of patients with colon cancer are elderly, clinical trials enroll mainly younger patients. Consequently, we are forced to depend on subgroup analyses, observational studies, and personal experience to guide recommendations. Decision-making in adjuvant therapy for colon cancer is increasingly complex, as we subdivide patients with stage II to III colon cancer by molecular as well as anatomic staging to predict which are likely to benefit from chemotherapy and then whether the addition of oxaliplatin to 5-fluorouracil (5-FU) is worth the toxicity. It is likely that the tumor biology of younger and older patients differs, and more research is needed to dissect out the biologic heterogeneity of both the tumors and their elderly hosts to help guide treatment. We recognize that our evaluations should not solely be based on temporal age and factor physiology, pharmacology, psychology, functional status, and social support into these considerations. Older patients who are treated must be monitored closely for toxicities when undergoing treatment. Although there is a clear need for clinical trials in this population, treatment decisions confront us today in the absence of definitive evidence. How can we help our patients navigate through these important choices?

The IDEA (International Duration Evaluation of Adjuvant Chemotherapy) Collaboration: Prospective Combined Analysis of Phase III Trials Investigating Duration of Adjuvant Therapy with the FOLFOX (FOLFOX4 or Modified FOLFOX6) or XELOX (3 versus 6 months) Regimen for Patients with Stage III Colon Cancer: Trial Design and Current Status

The International Duration Evaluation of Adjuvant Chemotherapy (IDEA) collaboration was established to prospectively combine and analyze data from several randomized trials conducted around the world to answer whether a three-month course of oxaliplatin-based adjuvant therapy (FOLFOX4/modified FOLFOX6 or XELOX) is non-inferior to the current standard six-month treatment for patients with stage III colon cancer, with a primary endpoint of three years disease-free survival. The IDEA steering committee comprises two members from each group coordinating an individual trial and two members from a secretariat who coordinate combining of the data and management of the joint analysis. Members of the IDEA agreed to combine the data from their individual trials to enable definitive analysis consisting of at least 10,500 patients. With accrual of 8,797 patients at the end of February 2013, the IDEA is on track to achieve its accrual objective of at least 10,500 patients by the end of 2013.

Association between adherence to National Comprehensive Cancer Network treatment guidelines and improved survival in patients with colon cancer

BACKGROUND

The objective of the current study was to examine the impact of adherence to guidelines on stage-specific survival outcomes in patients with stage III and high-risk stage II colon cancer. The National Comprehensive Cancer Network (NCCN) has established working, expert consensus, and evidence-based guidelines for organ-specific cancer care, including care of patients with colon cancer.

METHODS

Patients who were diagnosed with colon adenocarcinoma between 1998 and 2002 were selected from within the National Cancer Data Base. The cohort was limited to patients who received their first course of treatment at the reporting facility. Pathologic variables, including tumor depth, lymph node status, and evidence of metastatic disease, were used to restage patients, and the patients were divided into low-risk and high-risk categories on the basis of criteria defined by the NCCN. Relative survival rates were calculated for the entire cohort, stratified according to adherence versus nonadherence to NCCN treatment guidelines.

RESULTS

In univariate analysis of treatment adherence patterns for both patient subgroups (high-risk stage II and stage III), several factors were associated with a higher rate of nonadherence in both groups, including older age (P < .001); Medicaid, Medicare, or uninsured status versus private insurance (P < .001); and subsequent treatment at a facility other than the facility at which the cancer was first diagnosed (P < .001). In multivariate analysis, multiple factors were associated with differences in relative survival, although analyses that included the year of diagnosis did not demonstrate significant differences over time.

CONCLUSIONS

The current study documented practice patterns in a heterogeneous population of patients with colon cancer and demonstrated a survival benefit for patients with stage III and high-risk stage II colon cancer who received treatment that adhered to NCCN guidelines. These data validate the current NCCN practice guidelines for colon cancer and support the concept of guideline-based metrics that can be compared across institutions to assess the quality of cancer care and to compare the quality of cancer care among institutions.

Adjuvant chemotherapy with FOLFOX for primary colorectal cancer is associated with increased somatic gene mutations and inferior survival in patients undergoing hepatectomy for metachronous liver metastases

OBJECTIVE

We hypothesized that metachronous colorectal liver metastases (CLM) have different biology after failure of oxaliplatin (FOLFOX) compared to 5-fluorouracil (5-FU) or no chemotherapy for adjuvant treatment of colorectal cancer (CRC).

BACKGROUND

It is unclear whether patients treated with liver resection for metachronous CLM after adjuvant FOLFOX for CRC have worse outcomes than those who received 5-FU or no chemotherapy.

METHODS

We identified 341 patients who underwent hepatectomy for metachronous CLM (disease-free interval ≥12 months, 1993-2010). Mass-spectroscopy genotyping for somatic gene mutations in CLM was performed in a subset of 129 patients.

RESULTS

Adjuvant treatment for primary CRC was FOLFOX in 77 patients, 5-FU in 169 patients, and no chemotherapy in 95 patients. Node-positive primary was comparable between FOLFOX and 5-FU but lower in the no-chemotherapy group (P < 0.0001). Median metastasis size was smaller in the FOLFOX group (2.5 cm) than in the 5-FU (3.0 cm) or no-chemotherapy (3.5 cm) groups, (P = 0.008) although prehepatectomy chemotherapy utilization, metastases number, and carcinoembryonic antigen levels were similar. Disease-free survival (DFS) and overall survival (OS) rates after hepatectomy were worse in patients treated with adjuvant FOLFOX [DFS at 3 years: 14% vs 38% (5-FU) vs 45% (no-chemo), OS at 3 years: 58% vs 70% (5-FU) vs 84% (no-chemo)]. On multivariate analysis, adjuvant FOLFOX was associated with worse DFS (P < 0.0001) and OS (P < 0.0001). Mutation analysis revealed ≥1 mutations in 57% of patients (27/47) after FOLFOX, 29% (12/41) after 5-FU, and 32% (13/41) after no chemotherapy (P = 0.011).

CONCLUSIONS

Adjuvant FOLFOX for primary CRC is associated with a high rate of somatic mutations in liver metastases and inferior outcomes after hepatectomy for metachronous CLM.

Clinical management of localized colon cancer with capecitabine

Large randomized trials demonstrated a benefit of adjuvant chemotherapy after resection of the primary colon cancer. It improves overall survival and reduces the risk of death, by 5% in UICC (Union Internationale Contre le Cancer) stage II and approximately 15%-20% in stage III. Fluoropyrimidines have been the standard drugs for the treatment of colon cancer since large randomized controlled trials demonstrated their efficacy and safety in treating patients suffering from this disease. Capecitabine is an orally administered fluoropyrimidine, which is preferably activated in tumor tissue to the active moiety 5-fluorouracil (5FU) and is cytotoxic through inhibition of DNA synthesis. It has proven equivalent efficacy and tolerability despite a changed toxicity profile compared to 5FU with less myelosuppression but more hand-and-foot syndrome. Capecitabine is well tolerated in elderly patients. The oral route of administration avoids frequent clinical visits as well as insertion of central venous catheters. The impact of the particular drug features on daily clinical practice is discussed in this review.

Mutation profiling and microsatellite instability in stage II and III colon cancer: an assessment of their prognostic and oxaliplatin predictive value

PURPOSE

The purpose of this study was to examine the prognostic and oxaliplatin predictive value of mismatch repair (MMR) status and common hot spot mutations, which we previously identified in stage II and III colon cancer.

EXPERIMENTAL DESIGN

Mutations in BRAF, KRAS, NRAS, MET, and PIK3CA were profiled in 2,299 stage II and III colon tumors from National Surgical Adjuvant Breast and Bowel Project (NSABP) clinical trials C-07 (n = 1,836) and C-08 (n = 463) with Type Plex chemistry and mass spectrometry. C-07 tested the worth of adding oxaliplatin to 5-fluorouracil plus leucovorin, and C-08 tested the worth of adding bevacizumab to FOLFOX. Cox proportional hazard models were used to assess prognostic or oxaliplatin predictive value of mutations for tumor recurrence, overall survival (OS), and survival after recurrence (SAR).

RESULTS

BRAF mutations were associated with MMR-deficient tumors (P < 0.0001), poor OS [HR, 1.46; 95% confidence interval (CI), 1.20-1.79; P ≤ 0.0002], and poor SAR (HR, 2.31; 95% CI, 1.83-2.95; P < 0.0001). Mutations in KRAS, NRAS, MET, and PIK3CA were not associated with recurrence, OS, or SAR. MMR-deficient tumors were associated with an improved prognosis based on recurrence (HR, 0.48; 95% CI, 0.33-0.70; P < 0.0001). Mutations and MMR status were not predictive for oxaliplatin benefit.

CONCLUSIONS

This study shows that BRAF mutations profiled from stage II and III colon cancer tumors were associated with poor SAR and validates and explains, at least in part, previous observations associating it with poor OS. Profiling of all of these mutations is warranted for future clinical trials testing new targeted therapies that block relevant signaling pathways. Such clinical trials are under development at NSABP.

Adjuvant therapy with fluorouracil and oxaliplatin in stage II and elderly patients (between ages 70 and 75 years) with colon cancer: subgroup analyses of the Multicenter International Study of Oxaliplatin, Fluorouracil, and Leucovorin in the Adjuvant Treatment of Colon Cancer trial

PURPOSE

Oxaliplatin combined with fluoropyrimidine improves survival in patients with stage III colon cancer. However, adjuvant chemotherapy with oxaliplatin is controversial in stage II and elderly patients.

PATIENTS AND METHODS

We performed subgroup analyses of stage II and elderly patients randomly assigned fluorouracil with leucovorin (FL) ± oxaliplatin (FOLFOX4) in the Multicenter International Study of Oxaliplatin/Fluorouracil/Leucovorin in the Adjuvant Treatment of Colon Cancer study. Comorbidities, severe adverse events, second cancers, management of relapse and death as a result of causes than other colon cancer were studied.

RESULTS

Two thousand two hundred forty-six patients were enrolled. Overall, 899 patients had stage II disease, including 330 low-risk and 569 high-risk patients. A total of 315 patients were ages 70 to 75 years. For stage II patients, the hazard ratio (HR) for comparing FOLFOX4 with FL was 0.84 (95% CI, 0.62 to 01.14) for disease-free survival (DFS), 0.70 (95% CI, 0.49 to 0.99) for time to recurrence (TTR), and 1.00 (95% CI, 0.70 to 1.41) for overall survival (OS). There was no interaction between treatment and stage or age. Low-risk stage II patients did not benefit from oxaliplatin. In high-risk stage II patients, the HR comparing FOLFOX4 with FL was 0.72 (95% CI, 0.51 to 1.01) for DFS, 0.62 (95% CI, 0.41 to 0.92) for TTR, and 0.91 (95% CI, 0.61 to 1.36) for OS. In elderly patients, the HR comparing FOLFOX4 with FL was 0.93 (95% CI, 0.64 to 1.35) for DFS, 0.72 (95% CI, 0.47 to 1.11) for TTR, and 1.10 (95% CI, 0.73 to 1.65) for OS.

CONCLUSION

The results of these subset analyses show no statistically significant benefit (OS and DFS) for the addition of oxaliplatin to FL as adjuvant treatment for either stage II and elderly patients.

Effect of adjuvant chemotherapy on survival of patients with stage III colon cancer diagnosed after age 75 years

PURPOSE

Few patients 75 years of age and older participate in clinical trials, thus whether adjuvant chemotherapy for stage III colon cancer (CC) benefits this group is unknown.

METHODS

A total of 5,489 patients ≥ 75 years of age with resected stage III CC, diagnosed between 2004 and 2007, were selected from four data sets containing demographic, stage, treatment, and survival information. These data sets included SEER-Medicare, a linkage between the New York State Cancer Registry (NYSCR) and its Medicare programs, and prospective cohort studies Cancer Care Outcomes Research and Surveillance Consortium (CanCORS) and the National Comprehensive Cancer Network. Data sets were analyzed in parallel using covariate adjusted and propensity score (PS) matched proportional hazards models to evaluate the effect of treatment on survival. PS trimming was used to mitigate the effects of selection bias.

RESULTS

Use of adjuvant therapy declined with age and comorbidity. Chemotherapy receipt was associated with a survival benefit of comparable magnitude to clinical trials results (SEER-Medicare PS-matched mortality, hazard ratio [HR], 0.60; 95% CI, 0.53 to 0.68). The incremental benefit of oxaliplatin over non-oxaliplatin-containing regimens was also of similar magnitude to clinical trial results (SEER-Medicare, HR, 0.84; 95% CI, 0.69 to 1.04; NYSCR-Medicare, HR, 0.82, 95% CI, 0.51 to 1.33) in two of three examined data sources. However, statistical significance was inconsistent. The beneficial effect of chemotherapy and oxaliplatin did not seem solely attributable to confounding.

CONCLUSION

The noninvestigational experience suggests patients with stage III CC ≥ 75 years of age may anticipate a survival benefit from adjuvant chemotherapy. Oxaliplatin offers no more than a small incremental benefit. Use of adjuvant chemotherapy after the age of 75 years merits consideration in discussions that weigh individual risks and preferences.

Long-term neurotoxicity effects of oxaliplatin added to fluorouracil and leucovorin as adjuvant therapy for colon cancer: results from National Surgical Adjuvant Breast and Bowel Project trials C-07 and LTS-01

BACKGROUND

Neurotoxicity from adjuvant treatment with oxaliplatin has been studied in patients with colorectal carcinoma in short-term studies, but, to the authors' knowledge, the current article is the first long-term assessment which reports the National Surgical Adjuvant Breast and Bowel Project (NSABP) investigation of whether excess neurotoxicity persists beyond 4 years.

METHODS

As part of a colorectal cancer long-term survivor study (LTS-01), long-term neurotoxicity was assessed in 353 patients on NSABP Protocol C-07 (cross-sectional sample). Ninety-two of these patients from LTS-01 also had longitudinal data and were reassessed 5 to 8 years (median, 7 years) after random assignment (longitudinal sample). Contingency tables compared cohorts, a mixed model compared neurotoxicity between treatments over time, and a Wilcoxon rank-sum test compared neurotoxicity between treatments (cross-sectional sample).

RESULTS

In the cross-sectional sample, the increase in mean total neurotoxicity scores of 1.8 with oxaliplatin was statistically significant (P = .005), but not clinically significant (a minimally important difference of 4 was reported at the long-term assessment). Patients who received oxaliplatin had increased odds of numbness and tingling in hands (odds ratio, 2.00; P = .015) and feet (odds ratio, 2.78; P < .001) versus patients who did not receive oxaliplatin. The magnitude of the oxaliplatin effect varied with time (P < .001) in the longitudinal sample, such that the oxaliplatin-treated group did not have significantly greater total neurotoxicity scores by 7 years.

CONCLUSIONS

At the long-term endpoint, there was no clinically significant increase in total neurotoxicity scores for patients who received oxaliplatin, but the specific neurotoxicities of numbness and tingling of the hands and feet remained significantly elevated for oxaliplatin-treated patients.

The evolution of adjuvant therapy in the treatment of early-stage colon cancer

Adjuvant treatment of colon cancer, one of the most common malignancies, is an important issue in oncology. This article describes the development of adjuvant therapy and how the 2 major evolution steps, the successes of fluoropyrimidines, and then of oxaliplatin, have been achieved, Problems and failures, such as those of targeted therapies, also are addressed to help us to overcome their limitations. Special situations, such as stage II disease and an elderly population in which adjuvant chemotherapy is still controversial, are reviewed from the clinician perspective. The synthesis of these data allows us to conceive a future development focused on translational research.

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.