Cancer Screening & PreventionJanuary 20, 2026·5 min read
By the CIRRUS Editorial Team — how we write and source this
Smoking cessation and lung cancer risk reduction timeline
Risk doesn't reset to zero immediately after quitting, but the reduction curve is more encouraging than many assume.
Lung cancer risk begins declining relatively soon after quitting compared to continued smoking, though it doesn't return to a never-smoker's baseline risk quickly — research generally shows risk continuing to decrease over the 10-15 years following cessation, with the steepest relative decline in the first several years.
This is distinct from some other smoking-related health risks that improve on a faster timeline — cardiovascular risk, for instance, has shown meaningful improvement within the first year or two of cessation in several studies, a notably faster curve than lung cancer risk reduction.
The benefit of quitting scales with how early it happens relative to total smoking history — someone who quits after 10 years of smoking has a different long-term risk trajectory than someone who quits after 30, though quitting produces a meaningful risk reduction at any point compared to continuing.
This extended but real risk reduction timeline is also the reasoning behind lung cancer screening eligibility extending to 15 years after cessation — risk during that window remains elevated enough above a never-smoker's baseline to warrant continued screening consideration.
This article is general health information, not medical advice, and doesn’t replace evaluation by your own physician. Talk to a doctor about anything specific to your own diagnosis or treatment.