Quitting smoking early was related to higher survival rates following a lung cancer diagnosis, in line with a latest study led by researchers at Harvard T.H. Chan School of Public Health. In comparison with those that never smoked and were being treated for non-small cell lung cancer (NSCLC), current smokers had 68% higher mortality and former smokers had 26% higher mortality.

Our participants’ smoking histories varied, with some having stopped smoking a couple of years before their diagnosis and others having stopped several many years before. This big selection gave us confidence in our results—that the good thing about pre-diagnosis smoking cessation persists even after lung cancer is diagnosed.”

David Christiani, Senior Writer, Elkan Blout Professor of Environmental Genetics

The study was published online in JAMA Network Open on May 5, 2023.

While most similar research has compared mortality amongst current smokers and never smokers, nearly all of the study’s participants were former smokers, allowing the researchers to concentrate on the impacts of smoking cessation.

The study followed 5,594 patients with NSCLC—which accounts for 85% of all lung cancer cases—enrolled within the Boston Lung Cancer Survival Cohort at Massachusetts General Hospital between 1992 and 2022. Of those participants, 795 had never smoked; 3,308 were former smokers; and 1,491 were current smokers. Participants accomplished 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. In the course of the study period, 3,842 of the participants died: 79.3% of the present smokers, 66.8% of the previous smokers, and 59.6% of the never smokers.

While never smoking was related to one of 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 advantages they accrued: For former smokers, doubling the years of smoking cessation before their lung cancer diagnosis was significantly related to prolonged survival. Conversely, doubling smoking-pack years was related to shorter survival amongst current and former smokers diagnosed with NSCLC.

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 didn’t account for different sorts of treatment participants were receiving.

Other Harvard Chan School co-authors included Xinan Wang, Christopher Romero-Gutierrez, and Jui Kothari.

Funding for the study got here from National Cancer Institute grant 5U01CA209414.

Source:

Harvard T.H. Chan School of Public Health

Journal reference:

Wang, X., et al. (2023) Prediagnosis Smoking Cessation and Overall Survival Amongst Patients With Non–Small Cell Lung Cancer. JAMA Network Open. doi.org/10.1001/jamanetworkopen.2023.11966.