Patients who quit smoking after receiving a diagnosis of non-small cell lung cancer may have an almost two-year survival benefit than those who continued to smoke.
Quitting smoking after receiving a diagnosis of early-stage non-small cell lung cancer may improve survival compared with continuing a smoking habit.
In the study published in the Annals of Internal Medicine, researchers observed this effect on overall survival (time from diagnosis when a patient is still alive) and progression-free survival (time during and after cancer treatment that a patient lives with the disease without worsening) over an average follow-up of seven years.
“We found that patients who (smoked and developed) lung cancer, could significantly benefit from quitting smoking even after they are diagnosed with cancer,” said lead study author Dr. Mahdi Sheikh, scientist at the International Agency for Research on Cancer, in an interview with CURE®. “These patients, on average, could live almost two years longer, and without the recurrence of their disease, than patients who did not quit smoking. I would say (a two-year) improvement in the survival time is a huge effect.”
Cigarette smoking is a major risk factor for non-small cell lung cancer, a subtype that makes up approximately 85% of all lung cancer cases, according to the study’s introduction. In addition, at least 80% of patients with non-small cell lung cancer have a history of smoking cigarettes, and between 40% and 50% of patients were current smokers when they received a diagnosis of non-small cell lung cancer.
“When we look at the statistics of patients with lung cancer, we see that almost 50% of patients (smoke) at the time of cancer diagnosis,” Sheikh said. “If we can convince this 50% to quit smoking, the ultimate effects on the global burden of lung cancer could be massive.”
To assess the effect of smoking cessation on survival and mortality, researchers analyzed data from 517 current smokers (mean age, 61 years; 89% men) who were diagnosed with early-stage non-small cell lung cancer (stages 1A to 3A). Data from these patients were originally collected before receiving any cancer treatment. For this study, current smokers were defined as those who smoked at least one cigarette per day for more than one year at the time of their lung cancer diagnosis. Patients were followed up each year for an average of seven years to determine tumor progression, vital status, therapeutic procedures and either recurrence or metastasis after diagnosis.
Of the patients in the study, 42.5% quit smoking after receiving a diagnosis of non-small cell lung cancer and 57.4% continued smoking. During follow-up, 63.2% of patients died from any cause, of whom 52.8% were reported to have died from their cancer. Tumor progression, which included local recurrence or metastasis, was recorded in 33.7% of patients.
Patients who quit smoking had a longer overall survival time than those who continued smoking (6.6 years versus 4.8 years). Compared with the patients who continued smoking, those who quit smoking had a higher five-year overall survival (60.6% versus 48.6%) and progression-free survival (54.4% versus 43.8%).
Researchers also performed an analysis where they adjusted the data for risk factors and other variables. Smoking cessation continued to be associated with a lower risk for cancer-specific mortality, all-cause mortality and disease progression.
The beneficial effects of smoking cessation were comparable in patients who were mild-to-moderate and heavy smokers, and in those with earlier- and later-stage cancer.
Sheikh mentioned that the effect of quitting smoking on survival may help squash the stigma often associated with a lung cancer diagnosis among smokers.
“Unfortunately, patients, at the time of cancer diagnosis, may feel fatalistic,” he said. “They might feel it is too late now (and) there is no point of quitting smoking. However, this study shows that even after being diagnosed with cancer, it is still very useful to stop smoking. The main message we want to tell (patients) that it is never late. Even if you get cancer, you can benefit a lot from quitting smoking, so they shouldn’t lose hope. The effect that we saw is comparable to the emerging and new therapeutics for lung cancer that are being investigated, which could cost thousands of dollars and might not be accessible for many patients, but (quitting smoking) is potentially feasible for all patients and is free. We encourage them to quit smoking after diagnosis, the earlier, the better. However, the patients should also be encouraged and supported by their physicians and the health care system to quit smoking”
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