Double Mastectomy and Inherited Breast Cancer
Study found procedure might cut risk of death in half for those with certain genetic mutations
The new study traced the cancer histories of nearly 400 women with stage 1 and stage 2 breast cancer who were diagnosed between 1977 and 2009. All the women came from families known to have mutations in their BRCA1 or BRCA2 genes. Most of the women had tested positive for a mutation themselves, and were diagnosed with cancer in their early 40s. They were followed for an average of 13 years.
When it came time for surgery, 209 women opted to remove only the breast affected by the cancer, while 181 had both breasts removed.
Over the course of the study, 79 women died of breast cancer -- 61 in the group that had only one breast removed and 18 in the group that had both breasts removed.
After controlling for other factors that might influence survival -- such as tumor size, age at diagnosis and whether the cancer had spread to the lymph nodes -- researchers found that having both breasts removed reduced a woman's chances of dying of breast cancer by 48 percent during the next 20 years.
The researchers said bilateral mastectomy seemed to do the most good in the second decade after diagnosis.
"If you have breast cancer and a BRCA mutation -- and if you're going to die of that breast cancer -- you'll likely die in the first 10 years," Narod said. "After the 10 years are up, in most cases, you should consider yourself cured of breast cancer."
"What that means is that women who died between years 10 and 20 didn't die of the first breast cancer, they died of a new [cancer], and you can prevent that," he said.
Narod said his study underscores the importance of genetic testing, especially for women who are diagnosed at a young age or who have a strong family history of the disease. For them, a positive genetic test should help guide treatment decisions.
Not all experts agree that this study is the last word, however.
Karin Michels, an epidemiologist at Brigham and Women's Hospital in Boston, said the decision to remove both breasts is a difficult choice for many women, and one that should be carefully considered.