Despite data showing that cigarette smoking is the number one risk factor for the development of lung cancer,1 and a leading cause of preventable disease, disability, and death in the United States, an estimated 30.8 million American adults continue to smoke cigarettes.2 Globally, the number of smokers has increased to an astounding 1.1 billion, resulting in nearly 8 million excess tobacco-related deaths—480,000 deaths each year in the United States alone related to illness caused by tobacco use or exposure to second-hand smoke.3 Smoking is so addictive that about 30% of survivors continue to smoke even after a lung cancer diagnosis.4

In addition to decreasing survival, smoking after a lung cancer diagnosis can result in increased treatment toxicity, higher risk of treatment failure, greater incidence of secondary primary tumors, and reduced quality of life.5 According to the results from a recent study investigating whether quitting smoking after a lung cancer diagnosis confers a beneficial effect on survival, smoking cessation was associated with a nearly 30% improvement in overall survival.6

The study was conducted by Saverio Caini, MD, PhD, Senior Medical Epidemiologist at the Institute for Cancer Research, Prevention, and Clinical Network, Florence, Italy, and Vieri Scotti, MD, Consultant Clinical Oncologist, Department of Oncology, Radiation Therapy Unit at Careggi University Hospital, Florence, and colleagues; they examined data presented in 21 articles published in MEDLINE and Embase between 1980 and 2021. The articles included information on more than 10,000 patients diagnosed with non–small cell lung cancer, small cell lung cancer, or lung cancer of an unspecified histologic subtype, and the impact on survival after quitting smoking at or around diagnosis or during treatment.

Quantifying the Risks of Smoking on Lung Cancer

According to the study authors, tobacco smoking promotes tumor growth, progression, and dissemination; decreases the efficacy of and tolerance to radiation and systemic therapies; and increases the risk of postoperative complications and secondary primary cancers, although the underlying biological mechanisms causing these potential effects are unknown….


1. Centers for Disease Control and Prevention: What are the risk factors for lung cancer? Available at Accessed July 15, 2022.

2. Centers for Disease Control and Prevention: Current cigarette smoking among adults in the United States. Available at Accessed July 15, 2022.

3. Centers for Disease Control and Prevention: Tobacco-related mortality. Available at Accessed July 15, 2022.

4. Burris JL, Studts JL, DeRosa AP, et al: Systematic review of tobacco use after lung or head/neck cancer diagnosis: Results and recommendations for future research. Cancer Epidemiol Biomarkers Prev 24:1450-1461, 2015.

5. Jassem J: Tobacco smoking after diagnosis of cancer: Clinical aspects. Transl Lung Cancer Res 8(suppl 1):S50-S58, 2019.

6. 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 17:623-636, 2022.

7. Zhang R, Lai L, Dong X, et al: SIPA1L3 methylation modifies the benefit of smoking cessation on lung adenocarcinoma survival: An epigenomic-smoking interaction analysis. Mol Oncol 13:1235-1248, 2019.