In January 2008, a study was published that found postmenopausal women who take combination hormone therapy for at least three years have a fourfold increased risk of developing invasive lobular breast cancer. The study also found, however, that short term use of estrogen/progestin hormone replacement therapy has little effect on the risk of invasive ductal breast cancer.

The findings are significant because, while lobular breast cancer accounts for only 15 percent of invasive breast cancers, it is usually hormonally sensitive and thought to be more treatable than ductal cancers, though difficult to detect.

“There’s a fairly appreciable risk of lobular cancer associated with the use of combination hormone replacement therapy,” said Dr. Christopher Li, author of the study.

Researchers said that if women do choose to use hormone therapy, they should use the lowest possible dose for the shortest amount of time – a message that hasn’t changed much since a Women’s Health Initiative study in 2003 first linked hormone replacement therapy to an increased risk of breast cancer.

Source: Michael Smith, “Hormone therapy linked to lobular breast cancer risk,” MedPage Today, January 15, 2008 (http://www.medpagetoday.com/HematologyOncology/BreastCancer/tb/7926).