Attributable Failure of First-line Cancer Treatment and Incremental Costs Associated With Smoking by Patients With Cancer

Abstract

Importance: Previous studies have shown that continued smoking among patients with cancer can increase overall and cancer-specific mortality, risk for second primary cancer, and risk for toxic effects of cancer treatment. To our knowledge, there have been no efforts to estimate additional costs for cancer treatment attributed to smoking. Objective: To model attributable incremental costs of subsequent cancer treatment associated with continued smoking by patients with cancer. Design, Setting, and Participants: For this economic evaluation, a model was developed in 2018 using data from a 2014 US Surgeon General's report that considered expected failure rates of first-line cancer treatment in nonsmoking patients, smoking prevalence, odds ratio of first-line cancer treatment failure attributed to smoking compared with nonsmoking, and cost of cancer treatment after failure of first-line cancer treatment. Main Outcomes and Measures: Attributable failures of first-line cancer treatment and incremental cost for subsequent treatment associated with continued smoking among patients with cancer. Results: Attributable treatment failures were higher under conditions in which high first-line cure rates were expected in nonsmoking patients compared with conditions in which low cure rates were expected. Peak attributable failures occurred under the conditions in which expected cure rates among nonsmoking patients ranged from 50% to 65%. Under the conditions of a 30% expected treatment failure rate among nonsmoking patients, 20% smoking prevalence, 60% increased risk of failure of first-line cancer treatment, and $100 000 mean added cost of treating a first-line cancer treatment failure, the additional incremental cost per 1000 total patients was estimated to be $2.1 million, reflecting an additional cost of $10 678 per smoking patient. Extrapolation of cost to 1.6 million patients with cancer diagnosed annually reflects a potential $3.4 billion in incremental cost. Conclusions and Relevance: The findings suggest that continued smoking among patients with cancer and the increase in attributable first-line cancer treatment failure is associated with significant incremental costs for subsequent cancer treatments. Additional work appears to be needed to identify optimal methods to mitigate these incremental costs.