The process of undergoing lung cancer screening can itself act as a catalyst for smoking cessation in heavy smokers, novel Australian data suggests.
The finding follows a five-year screening trial in which a third of baseline current smokers had quit by three years with “minimal intervention” other than annual screening, the researchers say.
Lung cancer screening is currently on the agenda in Australia, with a national program receiving the backing of the Medical Services Advisory Committee (MSAC) two months ago.
Under the proposed scheme, screening will be available for patients aged 50-70, who have a history of cigarette smoking of at least 30 pack-years.
If former smokers, they will need to have quit within the previous decade. The screening, conducted via low-dose CT scans, will be available every two years.
The study involved 235 current and former smokers (quit less than 15 years and ≥30-pack year smoking history) aged 60–74 years, who self-reported their smoking status every six months for five years. Some 108 were current smokers at enrolment.
Unlike the proposed scheme endorsed by MSAC, screening was conducted annually: at baseline, year 1 and year 2. Participants also received brief smoking cessation advice and generic Quitline materials.
But even with these limited interventions, 33% of current smokers at baseline had achieved sustained smoking abstinence (≥6 months) at 36 months.
This was a significantly better quit rate than would be expected among the general population, who would typically be expected to quit at rates of 15-21%, the researchers reported in Asia-Pacific Journal of Clinical Oncology (link here).
“This may indicate that screening is a ‘teachable moment’ to quit, given that unassisted quit rates of 5%-7% per year and 14.8% over 5.5 years are reported in general populations,” they wrote.
Nevertheless, level of nicotine dependence remained a key predictor of quitting success, according to the authors.
Five (4%) former smokers relapsed at any point during the study.
The odds of continued smoking increased by 40% for each additional unit on the Heaviness of Smoking Index measured at baseline, after controlling for comprehensive health and sociodemographic factors, they wrote.
Other significant predictors for abstinence/quitting included experience of lung cancer (first-degree relative affected), cardiovascular disease or stroke, extensive pack-years smoking, and age.
Interestingly, they did not find that CT scan result (false positive or true negative) was a significant predictor of prolonged smoking abstinence, although the researchers pointed out that finding occurred in the context of a relatively small study size.
“Although these data are important because they are the first Australian data on smoking in lung cancer screenees, we acknowledge our small sample size limits statistical precision,” they wrote.
Other issues included a “healthy volunteer effect” and a lack of Indigenous Australians in the study.
The authors concluded: “Although the optimal strategy to maximise smoking abstinence remains unknown in this population, lung cancer screening offers a unique opportunity to combine primary and secondary lung cancer prevention.”
“The challenge remains for tobacco control programs to develop effective, tailored smoking cessation interventions to fully realise the benefits of lung cancer screening.”