WASHINGTON, DC — The survival benefit for contralateral prophylactic mastectomy among women who do not have aBRCA gene mutation is less than 1% at 20 years, a new computer model suggests.
"We hope that by providing women with accurate and easily understood information about the potential benefits of contralateral prophylactic mastectomy, this may impact current trends," said Pamela Portschy, MD, from the University of Minnesota in Minneapolis.
These findings, which come at a time of increasing demand for the procedure by women with cancer in one breast, were presented here at the American College of Surgeons 2013 Annual Clinical Congress.
"This model provides long-term survival information to physicians and their patients when discussing breast cancer risk-reduction strategies," Dr. Portschy explained.
Her team used published data to compare the risks for contralateral breast cancer and mortality with and without prophylactic mastectomy in women 40 to 60 years of age with early-stage breast cancer and without the high-risk BRCA mutation. The analysis took age, breast cancer stage (I or II), and estrogen-receptor status into account.
Gains in life expectancy with prophylactic mastectomy ranged from less than 1 month in a 60-year-old woman with estrogen-receptor-positive, stage II breast cancer, to 6.3 months in a 40-year-old with estrogen-receptor-negative stage I disease.
The absolute overall difference in survival at 20 years ranged from 0.36% to 0.94% for the 2 patient groups.
For the majority of women, there is not a good oncological reason to do a prophylactic mastectomy," study discussant Isabelle Bedrosian, MD, from the University of Texas M.D. Anderson Cancer Center in Houston, told Medscape Medical News. "The risk of cancer in the other breast is low, there are alternative options other than surgery for many women, and in many instances, there are other causes of mortality that are greater than breast cancer," she said.
But, Dr. Bedrosian added, one limitation of the study is that it didn't take into account factors such as comorbidities and family history of breast cancer, which also influence a patient's risk calculation.
Speaking to reporters, Todd Tuttle, MD, chief of surgical oncology at the University of Minnesota, said that approximately 20% of women in the United States who have cancer in one breast undergo double mastectomies. This is a dramatic increase from about 1% in the 1990s, he said during a news conference.
Possible reasons for the increase, Dr. Tuttle noted, include improved mastectomy and breast reconstruction techniques, awareness of genetic breast cancer, and publicity about celebrities who undergo the procedure. However, "we're also concerned that women have misperceptions about their risk of contralateral breast cancer and the potential survival benefits of having both breasts removed," he added.
Misperceptions
Dr. Tuttle explained that previous data from his group suggest that women without the BRCA mutation estimate their risk to be about 30% to 40% at 10 years, which is the risk for women with the BRCA mutation. In fact, the risk without the mutation is only 4% to 5%.
He added that it's important to distinguish between a patient who has just been diagnosed with breast cancer and someone like Angelina Jolie, who has theBRCA mutation but does not have cancer. "She had a long time to decide what to do," he pointed out. "If you don't have breast cancer but you have the mutation, you have time. But generally women with a diagnosis of breast cancer don't have that luxury."
"I still do a lot of double mastectomies, but I hope that my patients are informed," Dr. Tuttle said.
"I do point out to my patients there's really no need to do this," Dr. Bedrosian told Medscape Medical News. "In some cases, that registers and in many cases it doesn't. We respect patient choices and patient autonomy. If they ultimately choose prophylactic mastectomy after much discussion and review, we move forward."
She added that "there's clearly a disconnect between rational decision-making and emotional decision-making. That's a hard thing for the medical profession to overcome with just a conversation about the data. I think we need to explore more structured conversations, and perhaps better tools like decision aids, which have been shown to be an important adjunct to help patients make more reasoned decisions. I think that's what we really need to explore to better align the data with patient choice."
Dr. Portschy, Dr.Bedrosian, and Dr.Tuttle have disclosed no relevant financial relationships.
American College of Surgeons (ACS) 2013 Annual Clinical Congress. Presented October 7, 2013.
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