First-line multiagent chemotherapy
Three randomized studies in patients with metastatic colorectal cancer demonstrated improved response rates, progression-free survival (PFS), and OS when irinotecan or oxaliplatin was combined with 5-FU/LV.[41,42,43] An intergroup study (NCCTG-N9741) then compared IFL with FOLFOX4 in first-line treatment for patients with metastatic colorectal cancer. Patients assigned to FOLFOX4 experienced improved PFS (median, 6.9 months vs. 8.7 months; P = .014; hazard ratio [HR], 0.74; 95% confidence interval [CI], 0.61–0.89) and OS (15.0 months vs. 19.5 months, P = .001; HR, 0.66; 95% CI, 0.54–0.82) compared with patients randomly assigned to IFL.[Level of evidence: 1iiA] Subsequently, two studies compared FOLFOX with FOLFIRI, and patients were allowed to cross over after progression on first-line therapy, respectively.[44,45][Level of evidence: 1iiDiii] PFS and OS were identical between the treatment arms in both studies. Since the publication of these studies, the use of either FOLFOX or FOLFIRI is considered acceptable for first-line treatment of patients with metastatic colorectal cancer.
The Bolus, Infusional, or Capecitabine with Camptosar-Celecoxib (BICC-C) trial evaluated several different irinotecan-based regimen in patients with previously untreated metastatic colorectal cancer: FOLFIRI, mIFL, and capecitabine/irinotecan (CAPIRI). The study randomly assigned 430 patients and was closed early due to poor accrual. The patients who received FOLFIRI had a better PFS than the patients who received either mIFL (7.6 months vs. 5.9 months, P = .004) or CAPIRI (7.6 months vs. 5.8 months, P = .015). Patients who received CAPIRI had the highest (grade 3 or higher) rates of nausea, vomiting, diarrhea, dehydration, and hand-foot syndrome. After bevacizumab was approved, the BICC-C trial was amended and an additional 117 patients were randomly assigned to receive FOLFIRI/bevacizumab or mIFL/bevacizumab. Although the primary endpoint of PFS was not significantly different, patients receiving FOLFIRI/bevacizumab had a significantly better OS (28.0 months vs. 19.2 months, P = .037; HR for death, 1.79; 95% CI 1.12 to 2.88). When using an irinotecan-based regimen as first-line treatment of metastatic colorectal cancer, FOLFIRI is preferred.[Level of evidence: 1iiDiii] (Refer to the PDQ summary on Nausea and Vomiting and refer to the Diarrhea section in the PDQ summary on Gastrointestinal Complications for information on diarrhea and dehydration.)
Randomized phase III trials have addressed the equivalence of substituting capecitabine for infusional 5-FU. Two phase III studies have evaluated FUOX versus CAPOX.[47,48] The AIO Colorectal Study Group randomly assigned 474 patients to either FUFOX or CAPOX. The median PFS was 7.1 months for the CAPOX arm and 8.0 months for the FUFOX arm (HR, 1.17; 95% CI, 0.96–1.43: P = .117), and the HR was in the prespecified equivalence range. The Spanish Cooperative Group randomly assigned 348 patients to CAPOX or FUOX. The TTP was 8.9 months versus 9.5 months (P = .153) and met the prespecified range for noninferiority.[Level of evidence: 1iiDiii] When using an oxaliplatin-based regimen as first-line treatment of metastatic colorectal cancer, a CAPOX regimen is not inferior to a FUOX regimen.