Bryant Lin, a clinical professor and primary care physician at Stanford University, was diagnosed with Stage 4 lung cancer in spring 2024 despite never having smoked. His diagnosis came after he experienced a persistent cough that lasted six weeks and failed to respond to typical allergy, asthma, and reflux treatments. At the time of diagnosis, the cancer had already spread to his liver, bones, and brain. Lin’s case highlights a growing health concern: lung cancer in nonsmokers.

Lung cancer is traditionally associated with cigarette smoking, but a rising number of cases occur in individuals who have never smoked. Lin noted that about 20% of lung cancer patients in the United States fall into this category. Last week, Pope Leo underwent surgery to remove part of his right lung due to adenocarcinoma, the most common type of lung cancer, and he is also reported to have never smoked.

Declining smoking rates in the U.S. and other countries have brought attention to lung cancer among nonsmokers, which is now the eighth leading cause of cancer-related death in the United States and the fifth worldwide. Researchers have identified distinct clinical and demographic characteristics for lung cancer in nonsmokers. A recent study found a rare genetic mutation concentrated in the southeastern U.S. that raises lung cancer risk 60-fold among never-smokers. Women who have never smoked are more than twice as likely to develop lung cancer compared to men in the same category. Additionally, the disease is more common among people of East Asian descent, though it remains unclear whether this link is genetic or environmental.

Other risk factors for lung cancer in nonsmokers include exposure to secondhand smoke, radon, air pollution, asbestos, and a family history of early-onset cancer. Historically, lung cancer was considered rare in the early 20th century, but it has since become the leading cause of cancer deaths globally, surpassing colon, breast, and prostate cancers combined in the U.S.

Despite advances in understanding the disease, stigma remains a challenge for all lung cancer patients. Both smokers and nonsmokers may face delayed diagnosis and treatment due to assumptions about who is at risk. Medical oncologist Haiying Cheng emphasized that lung cancer diagnoses should not be influenced by judgments about a person’s smoking history, advocating for a focus on individual risk and tumor biology instead.

Current U.S. screening guidelines recommend lung cancer screening mainly for smokers and former smokers aged 50 to 80. Experts suggest that as the prevalence of lung cancer in nonsmokers grows, screening criteria should shift toward risk-based approaches. For example, Taiwan has implemented a national early-detection program offering low-dose computed tomography scans to nonsmokers with a family history of lung cancer.

Since his diagnosis, Lin has actively worked to raise awareness about lung cancer in nonsmokers. He developed a course at Stanford Medical School based on his experience and continues to lead research at the Stanford Center for Asian Health Research and Education. He also partners with the Susan Wojcicki Foundation to promote screening and early detection and has founded a company focused on advancing lung cancer treatments.

Lin has been receiving targeted antibody therapy for a mutation common among nonsmokers, which has markedly improved his condition. Despite the generally poor prognosis for Stage 4 lung cancer, with a five-year survival rate of approximately 13%, Lin maintains hope and productivity nearly two and a half years after his diagnosis. He encourages others, including his own children, to consider early screening as new diagnostic tools, such as blood-based tests, may become available in the near future.