A study from a US perspective concludes that in elderly patients with metastatic colorectal cancer, new chemotherapy agents do improve survival time but the benefit is limited and the cost substantial.
The authors note that new chemotherapy agents for metastatic colorectal cancer have been considered as examples of high-cost but low value care: they have only limited effects on survival but are very expensive. To investigate this further, they compared trends in life expectancy and lifetime medical costs over the period of the drugs’ introduction: this technique has previously been used to demonstrate high cost-effectiveness for new treatments in myocardial infarction, treatment of diabetes, and low birth-weight infants, and lower cost-effectiveness for patients with lung cancer.
They obtained data on outcomes in patients with stage 4 colorectal cancer treated through the US Medicare system between January 1995 and December 2005 inclusive. They were divided into five groups based on date of diagnosis and related to the FDA approval dates of six new chemotherapy agents: irinotecan (14/6/1996); capecitabine (30/4/1998); oxaliplatin (9/8/2002); and bevacizumab and cetuximab (12 & 26/2/2004), respectively. They measured the proportion of patients receiving irinotecan, oxaliplatin, and bevacizumab within 6 months of diagnosis – data for capecitabine were unavailable, and only 2.7% received cetuximab. Finally, they constructed five-year survival curves for each group (using assumed rates from available data for the final years of the 4th and 5th groups), and calculated lifetime medical costs (in 2006 US dollars) from diagnosis.
There were 12,473 patients in the final sample, of whom 4665 (37.4%) received chemotherapeutic agents within 6 months of diagnosis. The proportion treated with chemotherapy drugs was similar across the study period, and among this group median survival time increased by 4.5 months, and costs in the 2-year window following diagnosis increased by $17,800.
Over the course of the study, life expectancy in the group receiving chemotherapy drugs increased by 6.8 months and lifetime costs by $37,100, giving an implied cost per life-year gained of $66,200 (95% confidence interval, $48,100 to $84,200). After discounting life-years and costs and adjusting for patients' health utility and out-of-pocket payments, the cost per quality-adjusted life-year gained is $99,100 (95% confidence interval, $72,300 to $125,900).
Based on their study, the authors conclude that life expectancy in elderly patients with colorectal cancer who were treated with chemotherapy drugs increased between 1995 and 2005. This came at a significant cost, however, of around $100,000 per QALY. This is significantly higher than generally accepted willingness-to-pay thresholds. Overall, they consider that Medicaid may find it difficult to sustain current open-ended policies for new chemotherapeutic agents as costs continue to rise.