Efficacy of second-line chemotherapy after a first-line triplet in patients with metastatic colorectal cancer

Background Exposing patients with metastatic colorectal cancer (MCRC) to all three active chemotherapeutic agents (oxaliplatin, irinotecan, fluorouracil) has improved survival. The benefit of second-line chemotherapy after a first-line triplet is not clearly defined. We evaluated the efficacy of second-line chemotherapy in patients who had received first-line triplet therapy. Methods The medical records of patients treated on a prospective trial of first-line triplet therapy were reviewed for second-line treatment. Univariate and multivariate analyses were performed to establish factors of prognostic significance. Results Of the 53 patients who received first-line triplet therapy, 28 (53%) received second-line chemotherapy [13 men; 8 with a colon primary; mutant KRAS in 10, wild-type in 15, and unknown status in 3; Eastern Cooperative Oncology Group performance status (PS) of 1 in 16 patients, PS 2 in 3, PS 3 in 2, and unknown in 7; involved organs: liver in 17 patients, lung in 16, and peritoneum in 8]. Second-line chemotherapy consisted of XELOX or FOLFOX in 13 patients, XELIRI or FOLFIRI in 12, and single-agent irinotecan in 3. Concurrent bevacizumab was given in 16 patients (57%), and cetuximab, in 2 (7%). Median survival was 28.0 months [95% confidence interval (CI): 22.8 months to 33.2 months] for patients receiving second-line therapy and 23.0 months (95% CI: 13.2 months to 32.8 months) for those not receiving it. Best response was partial in 6 patients (21%), stable disease in 11 (39%), and progressive disease in 11 (39%). Median progression-free survival was 4.8 months (95% CI: 2.4 months to 9.6 months), and overall survival was 15 months (95% CI: 9.6 months to 20.4 months). Conclusions Second-line chemotherapy after first-line triplet therapy in mete is feasible and suggests efficacy comparable to that reported for second-line therapy after a doublet, regardless of the agent used.