Pack-a-day young women smokers at higher breast cancer risk

SEATTLE, Feb. 10 (UPI) -- Young women who smoke a pack a day for a decade or more have a significantly higher risk of developing breast cancer, U.S. researchers say.

Dr. Christopher Li of the Fred Hutchinson Cancer Research Center in Seattle and colleagues conducted a population-based study involving 778 patients with estrogen receptor positive breast cancer and 182 patients with triple-negative breast cancer. The patients were ages 20 to 44 and were diagnosed from 2004 to 2010.

Estrogen receptor positive breast cancer is the most common sub-type of breast cancer, while triple-negative breast cancer is less common but tends to be more aggressive. The study included 938 cancer-free controls.

The study, published early online in the journal Cancer, found young women who were current or recent smokers and had been smoking a pack a day for at least 10 years had a 60 percent increased risk of estrogen receptor positive breast cancer. However, smoking was not related to a woman's risk of triple-negative breast cancer, the study found.