Up to 1 in 5 lung cancer patients are nonsmokers: study

Up to one in five people diagnosed with lung cancer globally aren't smokers, a study involving Australian researchers has found.

Lung cancer in nonsmokers, defined as having smoked fewer than 100 cigarettes in their lifetime, accounts for 15 to 20 percent of all lung cancer cases worldwide, said a review published by Australian and British researchers in the Journal of the American Medical Association.

Nonsmokers with lung cancer have higher rates of cancer-related gene mutations, which appear to influence the effectiveness of different treatments for those patients, according to a summary of the study published on the Australian Science Media Center website on Tuesday.

After reviewing 92 previous international studies on lung cancer in nonsmokers, the team, including Benjamin J. Solomon, a researcher at Australia's Peter MacCallum Cancer Center and University of Melbourne, found that most cancers in this group are adenocarcinomas, cancers that start in glandular cells.

From the previous research, the authors said nonsmokers at the highest risk of lung cancer are mostly those who are exposed to passive smoking, radioactive material, air pollution, and asbestos, and have a history of lung cancer in a first-degree family member, including parents and full siblings, according to the summary.