— “The challenge is to implement this goal into practice,” says editorialist
Going smoke-free after a diagnosis of early-stage non-small cell lung cancer (NSCLC) significantly reduced risks of overall and disease-specific mortality, according to a prospective study.
Over an average follow-up of 7 years, smoking cessation was associated with a 33% decreased risk of all-cause mortality (HR 0.67, 95% CI 0.53-0.85), a 25% decreased risk of lung cancer-specific mortality (HR 0.75, 95% CI 0.58-0.98), and a 30% reduced risk of disease progression (HR 0.70, 95% CI 0.56-0.89) among those with stage IA-IIIA NSCLC, after adjusting for potential confounders and risk factors, reported Paul Brennan, PhD, of the International Agency for Research on Cancer in Lyon, France, and colleagues.
“Given that at least 50% of active smokers with NSCLC 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,” they wrote in Annals of Internal Medicine.
Studies show that up to half of patients with NSCLC are current smokers at the time of diagnosis. However, Brennan and colleagues noted that there is a lack of evidence showing that smoking cessation upon diagnosis improves survival. Furthermore, they pointed out that the available evidence has mainly been generated from retrospective studies that measure smoking status at the time of diagnosis or treatment with no follow-up, or small retrospective studies with short follow-up.
This large prospective study recruited 517 patients (mean age 61, 88.5% men) from 2007 to 2016 from the N.N. Blokhin National Medical Research Centre of Oncology and City Clinical Oncological Hospital No. 1 in Moscow. Patients had received their cancer diagnosis but had not yet received any local or systemic treatments.
Patients were asked about chronic health conditions and their lifetime history of cigarette smoking. They were followed annually to determine vital status, tumor progression, and events after diagnosis, as well as therapeutic procedures received.
Of the 517 patients in the study, 220 (42.5%) reported that they had quit smoking (eight of whom relapsed during follow-up), and the remaining 297 patients (57.4%) continued smoking after diagnosis.
Over the follow-up period, there were 325 deaths (271 of which were cancer specific) and 172 cases of tumor progression. Median overall survival (OS) for the entire cohort was 5.2 years, with 3- and 5-year OS rates of 65.1% and 50.9%, respectively.
The adjusted median OS was 6.6 years among patients who quit smoking compared with 4.8 years for continuing smokers — a difference of 21.6 months (P=0.001). Median progression-free survival was 5.7 years among patients who quit smoking versus 3.9 years for continuing smokers (P=0.004).
The team also determined that smoking cessation was similarly protective no matter whether patients had earlier- or later-stage disease, were mild-to-moderate or heavy cigarette smokers, or received radiation therapy or chemotherapy.
The study was limited by its observational nature, the fact that exposure measurements were based on self-reporting, and the possibility that smoking cessation could be associated with unmeasured confounders of improved outcomes, Brennan and colleagues noted.
“More studies are required to confirm these findings,” they wrote.
The authors provide a strong rationale for making smoking cessation treatment a component of routine care for all cancer patients, noted Nancy A. Rigotti, MD, of Massachusetts General Hospital and Harvard Medical School in Boston, in an accompanying editorial.
She pointed out that not only does the evidence support the feasibility and effectiveness of establishing smoking cessation programs in oncologic settings, but that such treatment provides good value considering the cost-effectiveness of these programs and the downstream costs associated with continued smoking by cancer patients.
“Unfortunately, despite this strong case for action, tobacco treatment has yet to become a standard component of cancer care delivery,” Rigotti wrote, further suggesting that smoking cessation treatment must extend beyond larger cancer care centers to community centers and sites, where most patients receive their diagnosis and treatment.
While this study indicates it is not too late for cigarette smokers with cancer to benefit from becoming smoke-free, “the challenge is to implement this goal into practice,” she concluded.
- Mike Bassett is a staff writer focusing on oncology and hematology. He is based in Massachusetts.
The study was supported by the International Agency for Research on Cancer.
The authors reported no disclosures.
Rigotti reported relationships with the National Cancer Institute, Pfizer, Achieve Life Sciences, and UpToDate.
Annals of Internal Medicine
Annals of Internal Medicine
by Mike Bassett, Staff Writer, MedPage