P-073Oxaliplatin-based chemotherapy in patients aged at least 75 years with metastatic colorectal cancer: a post-hoc subgroup analysis if three phase II studies

Introduction: Patients older than 75 years of age are usually excluded from metastatic colorectal cancer (mCRC) studies. Based on combination chemotherapy regimens containing oxaliplatin, our group has conducted three phase II studies in recent years, enrolling a total of 138 patients aged > 70 years. A post-hoc subgroup analysis of 67 patients aged at least 75 years was included in the present study. Methods: Oxaliplatin was combined with capecitabine in two trials and with uracil-tegafur (UFT) plus leucovorin in the third study. In one of these, bevacizumab was also added to chemotherapy. The median age of treated patients was 77 years (range, 75 to 89 years), 38 patients (57%) were men, and all had a good performance status (0 or 1). Median OS and PFS were calculated using the Kaplan–Meier method and differences between the levels of possible prognostic factors were compared using the log-rank test in univariate analyses. A value of P < .05 was considered statistically significant. Statistical analyses were performed using SPSS version 21.0. The three studies were approved by the institutional review board of the San Carlo Hospital, Potenza, Italy (IRB approval number: 2002-148, 2004-001159-12 and 2010-019463-10, respectively). Results: All patients were assessed for toxicity and for response to treatment. The observed overall response rate was 45% (95% CI, 32.5% to 57.0%), comparable to younger patients (51%; 95% CI, 38.8 to 62.6%; P = .49). The estimated median overall survival (OS) time was 19.3 months (95% CI, 13.8 to 24.7 months), and median progression-free survival (PFS) time was 8.7 months (95% CI, 7.6 to 9.7 months). These results did not seem to differ from those in younger patients < 75 years (8.0 months for PFS, P = .588; 19.7 months for OS, P = .947, respectively). Twenty-three patients (34%) received a second-line therapy, in most cases an irinotecan-based regimen. Only 4 patients received a third-line treatment. Similarly, 32% of patients younger than 75 years received a second-line chemotherapy based on irinotecan. This difference was not statistically significant (P = .81). The most common grade 3-4 adverse events included diarrhea, fatigue, peripheral neuropathy, and neutropenia. In any case, the toxicity was never statistically different from that in younger patients. Conclusion: Our study shows that age alone should never be considered itself a contraindication to the use of even more aggressive chemotherapy schedules, where potentially useful, in the treatment of patients aged over 75 with mCRC. The use of a chemotherapy doublet comprising oxaliplatin in this subcategory of elderly patients should be restricted to highly selected cases. In this context, only the development of a careful geriatric assessment will allow us, from time to time, to opt for the most appropriate treatment for each individual patient.