Study shows survival benefits of smoking cessation after lung cancer diagnosis

ByJanel Miller

Current smokers with early-stage lung cancer who quit smoking after their diagnosis had improved overall and progression-free survival rates, according to a prospective cohort study.

Perspective from Nina Thomas, MD

To date, studies that investigated whether smoking cessation after a cancer diagnosis might improve patients’ chances of survival have only measured smoking status at the time of diagnosis or treatment without follow-up, or had a limited number of smokers and short follow-up, Mahdi Sheikh, MD, PhD, a physician and cancer epidemiologist at WHO's International Agency for Research on Cancer, and colleagues wrote in Annals of Internal Medicine.

The 5-year overall survival rate (60.6% vs. 48.6%; P = .001) and the progression-free survival rate (54.4% vs. 43.8%; P = .004) were both higher in patients who quit compared with those who continued smoking. — Reference: Sheikh M, et al. *Ann Intern Med*. 2021;doi:10.7326/M21-0252.

“Furthermore, it is not clear whether any effects of smoking cessation differ between mild to moderate smokers and heavy smokers or among those with earlier- versus later-stage tumors,” the researchers wrote.

Sheikh and colleagues followed 517 current smokers — most of them men — with a mean age of about 61 years who had non–small cell lung cancer and tumor stage between IA and IIIA. The study participants were recruited between 2007 and 2016 and followed annually through 2020. During the study, 297 patients told the researchers they quit smoking.

During an average follow-up of 7 years, 325 patients died; 271 died from cancer. The researchers documented 172 cases of tumor progression — either a local recurrence or metastasis. The adjusted median overall survival time was 21.6 months longer among patients who quit smoking compared with those who continued to smoke (6.6 vs. 4.8 years, P = .001). The 5-year overall survival rate (60.6% vs. 48.6%; P = .001) and the progression-free survival rate (54.4% vs. 43.8%; P = .004) were both higher in patients who quit compared with those who continued smoking. Compared with patients who continued smoking in the follow-up period, those who quit smoking had a 33% decreased risk for overall mortality and a 25% decreased risk for cancer-specific mortality.

The researchers also wrote that after adjusting for numerous factors, smoking cessation remained associated with a decreased risk for all-cause mortality (HR = 0.67; 95% CI, 0.53-0.85), cancer-specific mortality (HR = 0.75, 95% CI, 0.58-0.98) and disease progression (HR = 0.72, 95% CI, 0.56-0.92). Similar effects were seen among mild to moderate and heavy smokers and patients with earlier and later cancer stages.

“Given that at least 50% of active smokers with [non–small cell lung cancer] are thought to continue smoking after diagnosis, this provides an important opportunity to substantially improve overall and progression-free survival in this type of cancer,” Sheikh and colleagues wrote.

In 2019, the International Association for the Study of Lung Cancer recommended all physicians screen their patients with cancer for tobacco use and recommend tobacco cessation. In addition, the authors of a 2019 commentary in JAMA Network Open wrote that comprehensive cancer care should include making “effective smoking treatment an integral and essential component of cancer care for patients who smoke.”

In a related editorial, Nancy A. Rigotti, MD, founder and director of the Tobacco Research and Treatment Center at Massachusetts General Hospital, wrote the new findings “strengthen the case for making tobacco cessation treatment a standard component of routine health care for all patients with cancer.”

Regrettably, some of the efforts to ensure such treatments are provided are either “struggling to sustain viability” or not universally offered, according to Rigotti.

“It’s not too late for cigarette smokers with cancer and cancer survivors to benefit from becoming smoke-free,” she wrote. “We need to make this happen!”

References:

Fiore MC, et al. JAMA Netw Open. 2019;doi:10.1001/jamanetworkopen.2019.12264.

IASLC. Declaration from IASLC: Tobacco cessation after cancer diagnosis. www.iaslc.org/About-IASLC/News-Detail/declaration-from-iaslc-tobacco-cessation-after-cancer-diagnosis. Accessed July 26, 2021.

Rigotti NA. Ann Intern Med. 2021;doi:10.7326/M21-2997.

Sheikh M, et al. Ann Intern Med. 2021;doi:10.7326/M21-0252.

Perspective

Nina Thomas, MD

This is an interesting prospective study evaluating how smoking cessation after lung cancer diagnosis impacts survival. Sheikh and colleagues found overall and cancer-specific survival as well as progression-free survival was improved for patients who quit smoking.

Prior data have shown that smoking cessation among patients screened for lung cancer was associated with decreased all-cause mortality regardless of screening arm, and the reduction was greater when combined with screening with low-dose CT. So, it is not surprising that both overall survival and cancer-specific survival would improve with smoking cessation even after diagnosis of lung cancer.

Although I am not sure causation has been clearly established in the Sheikh study, the researchers demonstrated an association of smoking cessation with better survival. Is it possible that patients who are doing better have increased motivation to quit? However, this study could be a starting point to generate further investigation on how smoking cessation may specifically affect factors associated with improved survival, such as response to chemotherapy, targeted therapy and immunotherapy, development of mutations or resistance to targeted therapies, healing after surgical resection, lung cancer recurrence or development of a second primary lung cancer.

Another interesting finding in the Sheikh study is that less than half of patients diagnosed with lung cancer quit smoking, further highlighting the barriers to smoking cessation counseling even among patients diagnosed with lung cancer. Most patients who did quit did so within 3 months of diagnosis, which may suggest that the time of diagnosis may represent a prime opportunity to intervene. While all patients, regardless of diagnosis of lung cancer, stand to benefit from smoking cessation, I do believe this study highlights the importance of continued counseling and resources dedicated to smoking cessation among patients diagnosed with lung cancer undergoing treatment given its impact on survival.

Reference:

Kanodra NT, et al. Ann Am Thorac Soc. 2016;doi:10.1513/AnnalsATS.201604-286OC.

Nina Thomas, MD

Pulmonologist and critical care specialist, University of Colorado Hospital at the UCHealth Pulmonary Nodule Clinic-Anschutz Medical Campus
Assistant professor of pulmonary sciences and critical care, University of Colorado School of Medicine

Disclosures: Thomas reports no relevant financial disclosures.

Sources/Disclosures

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Source: Sheikh M, et al. Ann Intern Med. 2021;doi:10.7326/M21-0252.

Disclosures: Sheikh and colleagues report no relevant financial disclosures. Healio Primary Care could not confirm Rigotti’s relevant financial disclosures at the time of publication.

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Study shows survival benefits of smoking cessation after lung cancer diagnosis

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