Breast cancer prevention drug gives lasting protection, study finds [View all]

[Rhinodawg]

Drug Research Medical Research Drugs and Medicines Breast Cancer
There's a powerful alternative to prophylactic mastectomy for women at high breast cancer risk
Taking the cancer drug tamoxifen for five years drives down the incidence of breast cancer in women at high risk for the disease by close to 30%, researchers have found. And the medication's protective effects against breast cancer appear to last, unabated, for as long as 16 years after a woman stops taking it, a new study says.

The long-awaited IBIS-I trial (short for International Breast Cancer Intervention Study-I) found that tamoxifen was even more effective in preventing breast cancer in women who did not take hormone replacement medications. Women who took tamoxifen and did not take concurrent replacement hormones had a 38% decline in breast cancer diagnoses of any genetic variety over roughly 16 years of follow-up. And new diagnoses of estrogen-sensitive breast cancers -- the most common kind -- dropped by 45% among these women.

That means that for every 22 women who took tamoxifen for five years, there would be one fewer diagnosis of estrogen-sensitive breast cancer over a 20-year period. In an editorial published alongside the IBIS study, Rowan T. Chlebowski, a leading breast cancer researcher at Los Angeles BioMedical Research Institute, called that a "very favorable number."

This may be good news for the estimated 15% of women between the ages of 35 and 75 who have a roughly 20% lifetime risk of developing breast cancer (double the average woman's risk). While public attention has focused on prophylactic mastectomies, medications such as tamoxifen offer women at elevated breast cancer risk a vastly less drastic way to drive down the odds of developing such malignancies.

http://www.latimes.com/science/sciencenow/la-sci-sn-breast-cancer-prevention-drug-20141210-story.html