While most similar research has compared mortality among current smokers and never smokers, the majority of the study’s participants were former smokers, allowing the researchers to focus on the impacts of smoking cessation.
Smoking History and Lung Cancer Survival Rates
The study followed 5,594 patients with NSCLCwhich accounts for 85% of all lung cancer casesenrolled in the Boston Lung Cancer Survival Cohort at Massachusetts General Hospital between 1992 and 2022. Of these participants, 795 had never smoked; 3,308 were former smokers; and 1,491 were current smokers. Participants completed questionnaires about their smoking habits and other health and demographic information at baseline, with the researchers checking in on their survival every 12 to 18 months. During the study period, 3,842 of the participants died: 79.3% of the current smokers, 66.8% of the former smokers, and 59.6% of the never smokers.
While never smoking was associated with the best odds of survival after a lung cancer diagnosis, the findings showed significant associations between lower mortality and having quit smoking pre-diagnosis. The longer a patient went without smoking, the more health benefits they accrued: For former smokers, doubling the years of smoking cessation before their lung cancer diagnosis was significantly associated with prolonged survival.
The researchers noted that associations between survival and smoking history may vary depending on the clinical stage at which lung cancer was diagnosed, and that the study did not account for the different kinds of treatment participants were receiving.
Other Harvard Chan School co-authors included Xinan Wang, Christopher Romero-Gutierrez, and Jui Kothari.
Funding for the study came from National Cancer Institute grant 5U01CA209414.