The carcinogenic, biological mechanisms and deleterious effects of cigarette smoke exposure in lung cancer development and the modulation of treatment response are well documented.1 While about 85% of lung cancer cases worldwide continue to be attributed to smoking cigarettes, as many as 25% to 50% of patients with lung cancer continue smoking at diagnosis. The body of evidence examining the effect of smoking cessation on cancer outcomes continues to grow. Herein, we provide a brief review of the most recent studies demonstrating the indisputable benefit of smoking cessation on lung cancer control across the care continuum.
A recent cohort study by Wang et al. of 5,594 patients with non-small cell lung cancer (NSCLC) (all histological subtypes and stages) showed that quitting smoking before cancer diagnosis is associated with better overall survival (OS) [median OS was 51.2 months for people who formerly smoked; and 34.0 months for those who continued to smoke following a lung cancer diagnosis].2 This study also showed a significant correlation between the years since quitting and increasing survival benefit.
Caini et al. published a systematic review and meta-analysis of data from more than 10,000 patients with lung cancer, which showed a significant 29% improved median OS (summary relative risks (SRR) = 0.71) for those who quit before, at, or around the time of a lung cancer diagnosis.3
Gemine et al. recruited 646 newly diagnosed patients with NSCLC who actively smoke and followed them up for 2 years.4 Postdiagnosis smoking status was validated using exhaled carbon monoxide levels at 3, 6, 9, 12, and 24 months after recruitment. In this study, quitting smoking by 3 months postdiagnosis, without relapse, was associated with a 25% reduction in the risk of death over 2 years.
Additionally, recent evidence published in JAMA Oncology in October 2024 by Cinciripini et al.5 has reported on the greatest longitudinal (15-year follow-up) data set yet. This prospective study included 4,526 patients (20% thoracic malignancies) who enrolled in a smoking cessation program at MD Anderson Cancer Center. The study demonstrated that quitting smoking at 3, 6, and 9 months after a cancer diagnosis was associated with significant reductions in the risk of death over 15 years: a 25% reduction for quitting at 3 months; a 21% reduction for quitting at 6 months; and a 15% reduction for quitting at 9 months. Optimal survival outcomes were observed in patients who received tobacco treatment within 6 months of their cancer diagnosis, with their survival at the 75th percentile increasing from 2.1 years among people who continued to smoke compared to 3.9 years for those who quit smoking.
Cessation across the lung cancer experience has also proven to impact health outcomes. Sheikh et al.’s earlier findings (2021)6 in a 9-year prospective study with more than 500 patients with stage IA through IIIA NSCLC with an average 7-year follow-up aimed to determine the impact of quitting smoking, assessed annually via telephone surveys, on disease progression and mortality corroborate more recent findings. This study demonstrated a remarkable 21.6 months higher adjusted median overall survival for those who had quit smoking after diagnosis compared to those who had not (6.6 years vs. 4.8 years; P = 0.001). Postdiagnosis smoking cessation was also associated with a reduced risk of overall mortality, cancer-specific mortality, and disease progression.1 Notably, the survival benefits were consistent across all subgroups, including patients diagnosed at earlier stages and later stages, as well as those with > 40 pack-years smoking history and those who had smoked ≤ 40 pack-years.6
The evidence shared here demonstrates a positive correlation between cessation (especially in the first 3 to 6 months following a lung cancer diagnosis) and lung cancer control, as evidenced by positive lung cancer survival and reduction in all-cause mortality.
In conclusion, all patients should be screened for smoking, advised to quit, assisted in quitting, or referred for cessation evaluation and treatment as early as possible once a lung cancer diagnosis is established, regardless of histological type or stage. As a professional lung cancer community, we must offer smoking cessation counseling and treatment to modify our patients’ lung cancer outcomes and improve their overall health.
Reference List
- 1. Caliri AW, Tommasi S, Besaratinia A. Relationships among smoking, oxidative stress, inflammation, macromolecular damage, and cancer. Mutat Res Rev Mutat Res 2021;787:108365.
- 2. Wang X, Romero-Gutierrez CW, Kothari J, Shafer A, Li Y, Christiani DC. Prediagnosis Smoking Cessation and Overall Survival Among Patients with Non–Small Cell Lung Cancer. JAMA Network Open 2023;6(5):e2311966.
- 3. Caini S, Del Riccio M, Vettori V, et al. Quitting Smoking At or Around Diagnosis Improves the Overall Survival of Lung Cancer Patients: A Systematic Review and Meta-Analysis. J Thorac Oncol 2022;17(5):623–636.
- 4. Gemine RE, Davies GR, Lanyon K, et al. Quitting smoking improves two-year survival after a diagnosis of non-small cell lung cancer. Lung Cancer 2023;186:107388.
- 5. Cinciripini PM, Kypriotakis G, Blalock JA, et al. Survival Outcomes of an Early Intervention Smoking Cessation Treatment After a Cancer Diagnosis. JAMA Oncology [Internet] 2024 [cited 2024 Nov 29];Available from: https://doi.org/10.1001/jamaoncol.2024.4890
- 6. Sheikh M, Mukeriya A, Shangina O, Brennan P, Zaridze D. Postdiagnosis Smoking Cessation and Reduced Risk for Lung Cancer Progression and Mortality : A Prospective Cohort Study. Ann Intern Med 2021;174(9):1232–1239. doi:10.7326/M21-0252
