For smokers, new research suggests it really is never too late to quit.
The study found that folks who kick their habit after a lung cancer diagnosis will likely live longer than those who continue lighting up.
Investigators from Italy concluded that lung cancer patients who stop smoking at or around the time of their diagnosis can look forward to survival times nearly a third (29%) longer than patients who never stop.
"Smoking is by far the most important risk factor for lung cancer," said study author Dr. Saverio Caini. "So a large proportion of those receiving this diagnosis will be actively smoking when this happens. Thus, this question is relevant for many patients."
Lung cancer is typically characterized by relatively poor survival rates, added Caini, a senior medical epidemiologist at the Institute for Cancer Research, Prevention and Clinical Network in Florence. "Any chance of substantially improving your prognosis is worth pursuing," he said.
Caini noted that "persistent smoking has a negative effect on the immune system, increases the risk of surgery complications, and decreases the efficacy of radiation therapy. And it is probably the sum of all these effects -- and perhaps others that we still do not know -- that in the end allow quitters to have a better chance of surviving than continued smokers."
Dr. Andrea McKee, a volunteer spokesperson for the American Lung Association, highlighted a similar list of meaningful benefits.
For one thing, she agreed that treatments such as radiation and chemotherapy "are more effective in the absence of tobacco."
McKee also noted that the nicotine in cigarettes is known to promote tumor growth and progression in all cancers for which smoking is a known risk factor.
Therefore, "I am not surprised by the degree of benefit" linked to smoking cessation, she said.
The finding follows an analysis of 21 studies published between 1980 and late 2021. Collectively, they involved more than 10,000 patients with non-small cell lung cancer (the most common type), small cell lung cancer and/or lung cancers of unspecified type.
The review team only included studies that focused on patients who had quit smoking either when diagnosed with lung cancer, during treatment or in the 12 months just prior to diagnosis.
The results were published Jan. 4 in the Journal of Thoracic Oncology.
While they noted differences in study design, including types of treatment, the researchers said the data was solid enough to conclude that quitting smoking is "significantly associated" with notably longer disease-free or progression-free survival times.
Based on their findings, the team suggested smoking cessation programs should become a part of lung cancer treatment plans, so that patients get the encouragement and support they need to up their survival chances.
The bottom line, said Caini, is that quitting is "an effective therapy for lung cancer patients, tolerable by everyone and with no severe side effects, and with very low costs for the patient and the health system."
Indeed, Caini argues that quitting should be strongly encouraged at the outset of any cancer screening process, before patients get a firm lung cancer diagnosis, or even if they get an all-clear.
"Unfortunately, there are not enough smoking cessation programs in the U.S.," McKee said. "I suspect this is in large part due to underfunding of the service. Data such as this will hopefully incentivize policy makers and insurance companies to better reimburse for tobacco cessation services."
There's more on the link between smoking and lung cancer at the American Lung Association.
SOURCES: Saverio Caini, MD, PhD, senior medical epidemiologist, cancer risk factors and lifestyle epidemiology unit, Institute for Cancer Research, Prevention and Clinical Network, Florence, Italy; Andrea McKee, M.D., volunteer spokesperson, American Lung Association; Journal of Thoracic Oncology, Jan. 4, 2022