Comparison of toxicity profiles of fluorouracil versus oxaliplatin regimens in a large population-based cohort of elderly patients with colorectal cancer.

BACKGROUND: Population-based studies of adverse events are scarce. Our objective was to evaluate chemotherapy-associated adverse events among elderly colorectal cancer (CRC) patients treated in the community. PATIENTS AND METHODS: Data on elderly patients aged ≥65 years diagnosed with CRC at any stage between 2003 and 2005 were obtained from the Surveillance, Epidemiology, and End Results (SEER)-Medicare Database.
RESULTS: Of 46 692 patients assessed, 36 137 (77.4%) received no i.v. chemotherapy, 5472 (11.7%) received fluorouracil (5-FU) alone, 2284 (4.9%) received oxaliplatin-containing regimens, 1306 (2.8%) received bevacizumab-containing regimens but without oxaliplatin, and 1493 (3.2%) received other chemotherapy. Symptoms and laboratory test abnormalities were commonly found in elderly, even in those who had not received any i.v. chemotherapy. The addition of i.v. chemotherapy was associated with higher incidences of adverse events. Oxaliplatin-based regimens led to higher incidences in nausea, neutropenia, and neuropathy compared with 5-FU alone. Patients aged ≥70 years (n = 37 601, 80.5%) tended to experience higher rates of certain adverse events, including infection, anemia, delirium, and heart disease than patients aged 65-69 years (n = 9091, 19.5%).
CONCLUSIONS: Among community-dwelling elderly with CRC, the addition of i.v. chemotherapy and advanced age were associated with increasing adverse events. Appropriate selection of patients and assessment of social support may be important.