COMPARISON OF LUNG CANCER SCREENING GUIDELINES WITH OTHER MAJOR PREVENTIVE CARE SERVICES IN SMOKERS
Method: Using national data on the distribution of major risk factors in smokers, we simulated a panel of smokers aged 55-80 years. For each individual, we applied an existing quantitative model to estimate the gain in life expectancy associated with discussion of guidelines graded “A” or “B” by the US Preventive Services Task Force, controlling for patient characteristics (age, race, gender, lifestyle, and comorbidity). To estimate the probability that discussion of a guideline would result in patient action (for example, obtaining a lung CT), we applied estimates of individual adherence rates, characterized by guideline as “easy” or “difficult”. We assumed adherence rates of 70% for easy guidelines (including lung cancer screening) and 30% for difficult guidelines (including tobacco cessation) in the first year, with a steady decline thereafter. We rank-ordered guidelines by their increase in adherence-adjusted life expectancy, to compare the net benefits of lung cancer screening with other major preventive care recommendations.
Result: In a hypothetical 55-year-old white female current smoker with a 30 pack-year history, hypertension (BP=140/90), mildly elevated lipids (TC=240, LDL=110), obesity (BMI=30), and no family history of cancer, discussion of lung cancer screening was estimated to add 2 months to adherence-adjusted life expectancy. Discussion of lung cancer screening offered less health benefit than discussion of tobacco cessation (+6 months), blood pressure control (+4 months), and weight loss (+4 months); similar benefit to discussion of aspirin (+2 months); and more benefit than discussion of screenings for colorectal cancer and breast cancer (+1 month each). Therefore, despite the difficulty of quitting smoking, discussion of tobacco cessation was 3 times more likely to improve life expectancy than discussion of lung cancer screening. The rank-order of recommendations was similar for other races and genders, with the relative importance of discussing tobacco cessation highest in black males (+11 months for quitting smoking vs. +2 months for lung cancer screening). Discussion of lung cancer screening consistently offered more health benefit than discussion of screening for abdominal aortic aneurysm, which is guideline-recommended for male smokers, but offered <1 month of additional life expectancy.
Conclusion: Analytic models may help to put lung cancer screening guidelines in perspective.