Comparative and cost-effectiveness of oxaliplatin-based or irinotecan-based regimens compared with 5-fluorouracil/leucovorin alone among US elderly stage IV colon cancer patients.

Background: Clinical trials have shown a statistically significant disease-free survival benefit of oxaliplatin-based or irinotecan-based combination regimens for stage IV colon cancer. Less is known regarding the comparative effectiveness and cost-effectiveness of these agents among elderly patients. Whether the benefits of these agents justify the additional costs for elderly Medicare recipients is particularly policy relevant after US health care reform.

Methods: A cost-effectiveness analysis of oxaliplatin-based or irinotecan-based combination therapy versus 5-fluorouracil/leucovorin alone in elderly stage IV colon cancer patients was performed from a US Medicare perspective. Survival and direct medical costs were estimated using Surveillance, Epidemiology, and End Results-Medicare data sets for patients diagnosed from 2002 to 2005 with follow-up through 2007. Incremental cost-effectiveness ratios (ICERs) were calculated as costs per life-year gained, with sensitivity analysis estimating the cost per quality-adjusted life-year (QALY).

Results: Median improved overall survival with 5-fluorouracil/leucovorin alone, or irinotecan-based or oxaliplatin-based combination therapy was 0.99, 1.07, and 1.47 life-years, respectively. Costs per life-year gained for oxaliplatin-based or irinotecan-based combination regimens compared with 5-fluorouracil/leucovorin alone were $78,181 and $267,938, respectively. ICERs comparing oxaliplatin-based to irinotecan-based regimens were $40,230 per life-year gained or $160,920 per QALY.

Conclusions: Oxaliplatin-based or irinotecan-based combination therapy improves overall survival but also substantially increases direct medical costs compared with 5-fluorouracil/leucovorin alone when used in elderly US patients with stage IV colon cancer. Oxaliplatin-based regimens are more cost-effective than irinotecan-based regimens for treatment of elderly stage IV colon cancer patients in terms of cost per life-year gained, but not in terms of cost per QALY.