Study shows that nonsmall cell lung cancer patients who smoke but quit after their diagnosis have better overall survival, progression-free survival than patients who continue to smoke.
Say a treatment drug for nonsmall cell lung cancer (NSCLC) increased overall survival by 21.6 months and progression-free survival by the same amount among patients who smoke. That would be a pretty remarkable drug, especially because so many NSCLC patients are smokers. Roughly 80% of NSCLC patients have a smoking history and between 40% and 50% are smokers when they are diagnosed.
But it isn’t a drug that is associated with such large survival gains. It is smokers giving up the smoking habit that very likely resulted in their lung cancer
Research results reported in today’s Annals of Internal Medicine show that the adjusted median overall survival time of NSCLC patients who were current smokers when they were diagnosed but then quit was 6.6 years compared with 4.8 years among those who continued to smokers. The median progression-free survival of the NSCLC patients who smoked but quit was 5.7 years compared with 3.9 years for the patients who didn’t quit.
Other comparisons between the quitters and those who continued to smoke showed the same pattern of a strong, statistically valid association between smoking and better outcomes.
The people who volunteered to be in this study were patients at two hospitals in Moscow, N.N. Blokhin National Medical Research Center of Oncology and City Clinical Oncological Hospital No. 1. The researchers compared 297 NSCLC patients who continued smoking to 220 who quit. Patients were identified as current smokers if they smoked one cigarette day for more than a year before they were diagnosed. Of the quitters, 157 (71.3%) quit soon after they were diagnosed and before their first treatment and 33 (15%) quit after treatment started but within a year of when they were diagnosed.
This isn’t the first study to show that smoking cessation has benefits even for those who have been diagnosed with NSCLC. But it is more definitive because it is a large study with a fairly long follow-up period.
Researchers have come up with a variety of explanations for why patients who continue to smoke don’t fare as well as those who quit. For example, the cancer-causing carcinogens in tobacco smoke may promote tumor growth. That’s an exposure that those who quit smoking don’t experience.
In the discussion section of their paper, lead author Mahdi Sheikh, M.D., Ph.D., of the International Agency for Research on Cancer, which is part of the World Health Organization, and his colleagues write that NSCLC patients who smoke “may feel fatalistic and not recognize the beneficial effects of quitting smoking postdiagnosis.
They go on to say that their results “strongly suggest” that patients with lung cancer who smoke should be encouraged to stop at any time and at each visit after they are diagnosed with NSCLC.