In a cohort study reported in JAMA Network Open, Wang et al found that overall survival in patients with non–small cell lung cancer (NSCLC) who stopped smoking prior to their cancer diagnosis was better than overall survival among those who were current smokers at the time of their diagnosis.
Study Details
The study involved patients with NSCLC who were recruited to the Boston Lung Cancer Survival Cohort at Massachusetts General Hospital between 1992 and 2022.
Key Findings
Among the total of 5,594 patients with NSCLC included in the analysis, 795 (14.2%) were never-smokers, 3,308 (59.1%) were former smokers, and 1,491 (26.7%) were current smokers at time of diagnosis.
Median overall survival was 58.9 months (95% confidence interval [CI] = 51.9–67.4 months) among never-smokers, 51.2 months (95% CI = 47.7–54.6 months) among former smokers, and 34.0 months (95% CI = 29.1–42.3 months) among current smokers. In analysis adjusted for age, sex, histologic profile, and clinical stage, the hazard ratios for all-cause mortality were 1.26 (95% CI = 1.13–1.40, P < .001) among former smokers and 1.68 (95% CI = 1.50–1.89, P < .001) among current smokers vs never-smokers.
Among ever-smokers, doubling the years of smoking cessation was associated with significantly prolonged survival (HR = 0.96, 95% CI = 0.93–0.99, P = .003), whereas doubling of smoking pack-years was associated with nonsignificantly poorer survival (HR = 1.03, 95% CI = 0.98–1.07, P = .21).
In a subgroup analysis according to clinical stage at diagnosis, a history of smoking was associated with shorter overall survival among patients diagnosed with early-stage disease (HR = 1.37, P < .001, for former vs never-smokers; HR = 1.93, P < .001, for current vs never-smokers) compared with patients diagnosed with stage IIIB to IV disease (HR = 1.19, P = .01, for former vs never-smokers; HR = 1.43, P < .001, for current vs never-smokers).
The investigators concluded, “In this cohort study of patients with NSCLC, quitting smoking early was associated with lower mortality following a lung cancer diagnosis, and the association of smoking history with overall survival may have varied depending on clinical stage at diagnosis, potentially owing to the differing treatment regimens and efficacy associated with smoking exposure following diagnosis. Detailed smoking history collection should be incorporated into future epidemiological and clinical studies to improve lung cancer prognosis and treatment selection.”
David C. Christiani, MD, MPH, MS, of the Department of Environmental Health, Harvard T.H. Chan School of Public Health, Harvard University, is the corresponding author for the JAMA Network Open article.
Disclosure: The study was supported by a grant from the National Cancer Institute. For full disclosures of the study authors, visit jamanetwork.com.
