Cancer Research Lab

Findings from a new study confirm that lung cancer in people who have never smoked is more common in women than in men.

“With lung cancer persisting as the leading cause of cancer mortality in the US, research into the epidemiology of lung cancer in never smokers should be an important public health priority,” Dr. Heather A. Wakelee, from Stanford University School of Medicine in California, and colleagues emphasize in their report in the Journal of Clinical Oncology for February 10.

Smoking remains the main etiologic factor in lung cancer, the investigators note. As such, few studies have looked at the occurrence of this malignancy among nonsmokers.

Dr. Wakelee’s team assessed the epidemiology of lung cancer in never smokers by analyzing data from six large prospective cohorts: the Nurses’ Health Study, the Health Professionals Follow-up Study, the California Teachers Study, the Multiethnic Cohort Study, the Swedish Lung Cancer Register in the Uppsala/Orebro region, and the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study.

In never smokers between 40 and 79 years of age, the incidence rates of lung cancer in these cohorts were 14.4 to 20.8 per 100,000 person-years for women and 4.8 to 13.7 per 100,000 person-years and men.

The results also indicate that the lung cancers that affect never smokers are distinct from those typically seen in smokers. For example, cancers in never smokers respond differently to epidermal growth factor receptor inhibitors and are more likely to show adenocarcinoma histology.

The pathogenesis of lung cancer in never smokers is not completely understood, but second-hand smoke exposure probably plays a role.

“We know that secondhand smoke does increase the risk of lung cancer,” co-author Dr. Ellen Chang said in a statement. “So, it’s likely that a lot of these cases we observe are attributable to that.”