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Grade 3/4 neutropenia is a limiting factor in second-line FOLFIRI following FOLFOX4 failure in elderly patients with metastatic colorectal cancer.

Previous studies have reported improved outcomes for elderly patients with metastatic colorectal cancer (mCRC) treated with oxaliplatin or irinotecan as first-line chemotherapy. However, few studies regarding second-line chemotherapy with oxaliplatin or irinotecan are currenlty available. We analyzed retrospectively the efficacy and toxicity in elderly patients (median age, 74 years) treated with second-line FOLFIRI following first-line FOLFOX4 failure. From March 2005 to January 2008, 35 elderly patients with mCRC received first-line FOLFOX4 comprising leucovorin, 5-FU and oxaliplatin followed by second-line FOLFIRI comprising leucovorin, 5-FU and irinotecan. The median number of treatment courses with FOLFIRI was 5 (range 2-32). One patient responded to the treatment. The disease control rate was 38.2%. The median time to treatment failure was 3 months, and the median overall survival (OS) time from the beginning of first-line chemotherapy was 20.7 months. The incidence of grade 3/4 neutropenia was 71.4%, while febrile neutropenia was 11.4%. The incidence of non-hematological toxicity was low. The use of the three active drugs, 5-FU, oxaliplatin and irinotecan, in mCRC produced the longest OS in elderly as well as in younger patients. However, the elderly patients treated with second-line FOLFIRI had a high rate of hematological toxicity. Second-line FOLFIRI may therefore be used with caution in the elderly.