Young women who have smoked a pack a day for a decade or more have a significantly increased risk of developing the most common type of breast cancer, according to a study.
The study, published Feb. 10 on the website of the journal Cancer, indicates that an increased risk of breast cancer may be another health risk incurred by young women who smoke.
The majority of recent studies evaluating the relationship between smoking and breast cancer risk among young women have found that smoking is linked with an increased risk, according to background information in the study. However, few studies have evaluated risks according to different subtypes of breast cancer.
To investigate, Christopher Li, MD, PhD, of the Fred Hutchinson Cancer Research Center in Seattle, and his colleagues conducted a population-based study consisting of 778 patients with estrogen receptor positive breast cancer and 182 patients with triple-negative breast cancer. Estrogen receptor-positive breast cancer is the most common subtype of breast cancer, while triple-negative breast cancer is less common but tends to be more aggressive.
Patients in the study were ages 20 to 44 and were diagnosed from 2004-10 in the Seattle-Puget Sound metropolitan area. The study also included 938 cancer-free controls.
The researchers found that young women who were current or recent smokers and had been smoking a pack a day for at least 10 years had a 60% increased risk of estrogen receptor positive breast cancer. In contrast, smoking was not related to a womans risk of triple-negative breast cancer.
The health hazards associated with smoking are numerous and well known, Li said in a news release. This study adds to our knowledge in suggesting that with respect to breast cancer, smoking may increase the risk of the most common molecular subtype of breast cancer but not influence risk of one of the rarer, more aggressive subtypes.
Cancer is a peer-reviewed journal of the American Cancer Society. Study abstract: http://onlinelibrary.wiley.com/doi/10.1002/cncr.28402/abstract