An increasing number of lung cancer cases—up to 25%—are being diagnosed in people who have never smoked, according to the National Institutes of Health.
The trend is especially common among women, people of Asian descent, and those with a family history of the disease.
“Lung cancer in never-smokers is emerging as a separate disease entity with distinct molecular characteristics that directly impact treatment decisions and outcomes,” said Andreas Wicki, an oncologist at the University Hospital Zurich, in an interview with the BBC.
“When we see 30- or 35-year-olds with lung cancer, they are usually never-smokers,” he added.
Researchers are now focusing on environmental exposures and genetic mutations. At the University of California, San Diego, Dr. Maria Landi and Dr. Ludmil Alexandrov are leading efforts to examine factors like air pollution.
The NIH noted, “People with high exposure to fine-particle air pollution… were 1.6 times more likely to have mutations in the gene for TP53.”