Efficacy and safety of FOLFIRI regimen in elderly versus nonelderly patients with metastatic colorectal or gastric cancer

Background. Irinotecan-based chemotherapy is a standard backbone of therapy in patients with metastatic colorectal cancer (CRC) or gastric cancer (GC). However, there is still a paucity of information concerning the efficacy and safety of irinotecanbased regimens in elderly patients. Patients and Methods. Using the patient cohort (n51,545) from the UGT1A1 genotype study, we compared the efficacy and safety between elderly and nonelderly patients with metastatic CRC (n5934) or GC (n5611) who received first-or second-line FOLFIRI (irinotecan, leucovorin, and 5-fluorouracil) chemotherapy. Results. Despite lower relative dose intensity in elderly patients, progression-free survival and overall survival were similar between elderly (age ≥ 70 years) and nonelderly (<70 years) patients in the CRC cohort (hazard ratio [HR], 1.117; 95% confidence interval [CI], 0.927-1.345; p5.244, and HR, 0.989; 95% CI, 0.774-1.264; p5.931, respectively) and the GC cohort (HR, 1.093; 95% CI, 0.854-1.400; p5.479, and HR, 1.188; 95% CI, 0.891-1.585; p5.241, respectively). In both cohorts, febrile neutropenia (22.1% vs. 14.6% in CRC cohort and 35.2% vs. 22.5% in GC cohort) and asthenia (grade 3: 8.4% vs. 1.7% in CRC cohort and 5.5% vs. 2.9% in GC cohort) were more frequent in elderly patients. In the CRC cohort, mucositis and anorexia were more frequent in elderly patients. In the GC cohort, nausea and vomiting were less frequent in elderly patients. Conclusion. The efficacy of the FOLFIRI regimen was similar between elderly and nonelderly patients in both the CRC and the GC cohorts. However, special attention should be paid to elderly patients because of increased risk for febrile neutropenia and asthenia.