At least 20% of people who develop lung cancer are nonsmokers, according to Mayo Clinic physician Catherine Madaffari, M.D.
Notes on verification
Direct quote confirmed via Mayo Clinic News Network, and the 20% figure is corroborated by American Cancer Society and Yale Medicine, though some epidemiological studies cite slightly lower ranges (10-15%) depending on methodology.
Sources
- Anyone With Lungs Can Get Lung Cancer (newsnetwork.mayoclinic.org)
- https://www.yalemedicine.org/conditions/lung-cancer-in-nonsmokers (yalemedicine.org)
- https://www.cancer.org/cancer/latest-news/why-lung-cancer-strikes-nonsmokers.html (cancer.org)