Study: Lung Cancer Higher in Non-Smokers

A U.S. of team of researchers says the incidence of lung cancer in non-smokers is higher — especially in women — then previously thought.

Researchers at the Stanford University School of Medicine and the Northern California Cancer Center used multiple collections of data from both the United States and Sweden that, in total, tracked the incidence of lung cancer in more than 1 million people from the ages of 40 to 79.

They found that for women, the lung-cancer incidence rate in never-smokers ranged from 14.4 to 20.8 cases per 100,000 person-years. In men it ranged from 4.8 to 13.7 incidents. For current smokers, the rates were about 10 to 30 times higher.

If these statistics are representative of the overall population of the United States, the authors infer that around 8 percent of lung-cancer cases in males and close to 20 percent of cases in females are among never-smokers, according to the study published Saturday in the Journal of Clinical Oncology.

Ellen Chang, an epidemiologist at the Northern California Cancer Center and a member of the Stanford Comprehensive Cancer Center, cautioned that it is difficult to study many of the factors that could affect these statistics, but secondhand smoke could explain part of the gender difference.