Purpose: To estimate the cost-effectiveness of the five chemotherapeutics approved for metastatic colorectal cancer since 1996 as a group. These drugs, bevacizumab (Avastin) in particular, are often cited as examples of high cost/low value medical care.
Method: We evaluated cost-effectiveness by comparing trends in life expectancy and costs among patients treated with chemotherapy. Using the SEER-Medicare database (Medicare claims linked with SEER tumor registry records), we identified a sample of 5,174 fee-for-service Medicare beneficiaries age 66+ diagnosed with metastatic colorectal cancer in 1995-2005. The data include Medicare claims through 2006 and vital status through 2007. To calculate life expectancy, we applied historical survival rates to characterize the complete survival curve beyond two years post-diagnosis. To model lifetime medical spending, we used the “phase of care” approach. This approach combines the estimated survival curves with estimates of post-diagnosis costs, end-of-life costs, and “ongoing” costs between diagnosis and death. Costs represent spending by the Medicare program in 2006 dollars and include costs for unrelated medical conditions (e.g. diabetes). We used bootstrapping to estimate confidence intervals.
Result: Patients treated with chemotherapy before any of the newer drugs were approved had a life expectancy of 17.4 months and lifetime costs of $64,000. Patients treated with chemotherapy after all of the new drugs were approved (February 2004) had life expectancy of 24.2 months and lifetime costs of $102,000. The incremental cost-effectiveness of the new drugs as a group, which is calculated by dividing the change in costs by the change in survival time, is $68,000 [95% CI $47,000-$86,000]. The proportion of patients receiving chemotherapy was stable over the study period. Among patients not treated with chemotherapy, costs and survival time were unchanged.
Conclusion: The cost-effectiveness of new chemotherapeutics for metastatic colorectal cancer is not out of line with the cost-effectiveness of other commonly used medical treatments, suggesting that new chemotherapeutics have been unfairly maligned as high cost/low value medical care. Our estimates of survival and cost trends are based on real-world use patterns. The absence of changes in survival or costs among a quasi-control group – patients who did not receive chemotherapy – suggests that our estimates are unconfounded.
Candidate for the Lee B. Lusted Student Prize Competition