Pope Leo XIV’s lung cancer highlights growing number of nonsmokers diagnosed with the disease – and younger people too

Lung cancer is no longer just a disease of older men who smoke. Over the past 15 years, the disease has increasingly affected women, people who have never smoked, and younger individuals. For example, lung cancer is now the leading cause of cancer death among women, surpassing deaths from breast, ovarian, and colorectal cancer combined. While lung cancer rates have decreased by 43% for men over the last 44 years, they have risen by 79% for women during the same period. Notably, for the first time, more young women than men are being diagnosed with lung cancer. The diagnosis of Pope Leo XIV, a nonsmoker, has drawn attention to this shift in the disease's profile.

Smoking remains a major risk factor for lung cancer, but it is no longer the only one. Women who started smoking later than men and used filtered cigarettes—common in past decades—face a higher risk of adenocarcinoma, a type of lung cancer that develops in the outer parts of the lungs. Filtered cigarettes may distribute tobacco smoke differently, increasing this risk. Additionally, women appear more susceptible to the carcinogenic effects of tobacco smoke, including secondhand smoke, and may develop lung cancer after fewer years of smoking compared to men. However, about 20% of women diagnosed with lung cancer today have never smoked, a higher proportion than in men.

Beyond smoking, several other factors contribute to lung cancer risk. These include exposure to environmental hazards such as asbestos, a mineral once widely used in construction that can cause lung damage when inhaled. Radon, a naturally occurring radioactive gas found in some homes, is another risk factor. Air pollution, workplace chemicals like arsenic, beryllium, cadmium, silica, and nickel, as well as the potential risks of e-cigarette and marijuana smoke, are also under study. Genetics plays a role too, with some families showing a higher predisposition to lung cancer due to inherited gene mutations, similar to how BRCA1 and BRCA2 genes increase breast cancer risk.

Lung cancer screening in the U.S. is currently recommended for adults aged 50 to 80 who have smoked at least one pack of cigarettes per day for 20 years, as well as current smokers and those who quit within the last 15 years. Updated in 2021, these guidelines now include younger patients with less smoking history, expanding eligibility by 40% for women. Screening typically involves a low-dose CT scan, a type of imaging that uses low levels of radiation to detect early-stage tumors. Despite the availability of screening, less than 6% of eligible smokers pursue it, compared to over 70% of eligible women who undergo breast cancer screening.

Lung cancer is often diagnosed at later stages, especially in nonsmokers and younger patients, due to delayed recognition of symptoms. Common symptoms include a persistent cough, shortness of breath, fatigue, and pain in the chest or shoulders, which may be mistaken for other conditions. Women tend to be diagnosed at slightly younger ages than men and may have better outcomes, particularly if their tumors have specific molecular changes that can be targeted with therapies. Advances in targeted therapies and immunotherapies—treatments that attack cancer cells or boost the immune system—have improved prognosis for many patients. However, early detection remains critical for successful treatment.