April 18, 2011 — Most women with breast cancer who elect to undergo contralateral prophylactic mastectomy (CPM) — a procedure that is occurring with increasing frequency — are not at high risk for contralateral breast cancer, but make their decisions for other reasons, according to a new study published online April 4 in the Journal of Clinical Oncology.
"This decision is very complex and it behooves the surgical community to really try to understand the factors that are important to women in making this decision," lead author Tari A. King, MD, from Memorial Sloan-Kettering Cancer Center in New York City, told Medscape Medical News.
"Many women estimate their risk of developing a second breast cancer to be much higher than it is. We need to ensure that we are counseling them that the risk of contralateral breast cancer in the modern era is actually quite low, much lower than it was 15 or 20 years ago," Dr. King said.
She and her colleagues noticed that more contralateral prophylactic mastectomies were being done at their institution and decided to take a closer look at their data to see if they could identify a trend.
They reviewed their prospectively maintained database of all women who undergo breast cancer surgery at Memorial Sloan-Kettering and identified 2965 women who had stage 0, 1, 2, or 3 unilateral breast cancer treated with mastectomy between 1997 and 2005.
Over that time period, 407 women (14%) underwent CPM. Consistent with what has been seen in other studies that have shown an increasing rate of CPM, the investigators found that their rate of the procedure increased 3-fold over the 8-year period, from 6.7% in 1997 to 24% in 2005 (P < .0001).
Just 52 (13%) of the women who had CPM had BRCA mutations or previous mantle radiation — the 2 factors that are associated with an increased risk for contralateral breast cancer and are accepted indications for the procedure.
Independent predictors of CPM include white race (odds ratio [OR], 3.3), immediate breast reconstruction (OR, 3.3), family history of breast cancer (OR, 2.9), magnetic resonance imaging at diagnosis (OR, 2.8), age younger than 50 years (OR, 2.2), noninvasive histology (OR, 1.8), and previous attempt at breast conservation (OR, 1.7).
No Proven Survival Benefit With CPM
"We need to have a very balanced discussion of what their actual risk of contralateral breast cancer is, educate them that there has not been any proven survival benefit from removing their contralateral breast, and try to understand what is motivating them to make this decision — in the context of not only what we consider important end points but also what the woman considers to be an important end point," Dr. King said.
It is possible that some women will come to regret the decision to have CPM, she added.
"It would be good to know if they are satisfied with their choice many years later." For example, some studies have shown that a significant minority of patients — as many as 30% — report negative feelings about breast reconstruction, Dr. King noted. "They report decreased satisfaction with body image and decreased sexual functioning. Even though it is a minority, 30% is still a large number of women. There has not been much work done to understand whether satisfaction and expectations remain positive many years after this type of surgery."
Fear Might Motivate the Choice
Despite current reports demonstrating that the risk of a woman developing cancer in her other breast after modern breast cancer treatment is low — from 0.1% to 0.3% per year — fear of recurrence can be very real and might influence a woman's decision to undergo the prophylactic removal of the healthy breast.
There is also a lot of anxiety associated with ongoing breast cancer screening and surveillance and the potential need for biopsies. "These factors may also prompt a woman to choose CPM. But right now, we don't have any studies that capture how significant these factors are in a woman's decision-making process" Dr. King said.
In an accompanying editorial, Seema A. Khan, MD, from Northwestern University, Evanston, Illinois, writes that this study adds valuable information regarding the factors that are associated with the increasing use of CPM.
"The report by King et al adds urgency to the need to resolve the paradox between progress in breast cancer therapy and the increasing use of a radical and unproven procedure," Dr. Khan writes. "It is important that future studies of the consequences of bilateral mastectomy (with or without reconstruction) address not only the early complications of the procedure, but also the long-term impact on quality of life, including overall satisfaction, sexuality, and chronic pain, and balance this against the risk of adverse cancer outcomes and the risks of surveillance."
She suggests prospective studies that enroll patients when they are deciding whether or not to have CPM, and then observing them for quality-of-life outcomes. Embedding such a study into parallel adjuvant therapy studies would be the most efficient, she said.
Dr. King and Dr. Khan have disclosed no relevant financial relationships.
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Cite this: Rise in Contralateral Prophylactic Mastectomy Not Linked to High Risk - Medscape - Apr 18, 2011.