Breast cancer is one of the few major illnesses for which physicians may not recommend a specific treatment option. North American women are more likely to opt for precautionary breast surgery when physicians don’t specifically counsel against it, according to a new study.

The research, presented at the American Society of Breast Surgeons Annual Meeting in Las Vegas, also demonstrates how clarity during consultations and the capability of clinical facilities also play important roles influencing a woman’s breast cancer treatment choices.

There is more than one type of preventive breast surgery, but this study looked only at cases in which cancer has been diagnosed in only one breast. This form of prophylactic breast surgery, called a contralateral prophylactic mastectomy, entails removing the healthy breast at the same time as the cancerous breast. The procedure can reduce the risk of breast cancer recurrence in women who have a strong family history of breast or ovarian cancers, and in women who have a genetic mutation that makes breast cancer more likely.

‘While effective for such groups,’ explained Dr Andrea Covelli, lead author and a University of Toronto general surgery resident, whose research work was supervised by Dr Nancy Baxter of St. Michael’s Hospital. ‘The number of prophylactic mastectomies across North America has risen among women without these underlying conditions — among women who have only an average risk of developing cancer in their non-cancerous breast.’

Previous national studies have shown that instances of prophylactic breast surgery among early-stage, average risk women have increased nearly twelve-fold in the US over the last decade. In Canada, rates increased by 140% between 2008 and 2010.

In the US, some states legislate that surgeons present all treatment options to patients. The research found that surgeons complied in the 20 states with such legislation, but generally surgeons did not recommend one procedure over another, but encouraged patient choice. Canadian surgeons discussed similar surgical options with their patients. However, they more often specifically recommended breast-conserving surgery and counselled against prophylactic mastectomies.

Immediate reconstruction was associated with the choice of prophylactic mastectomy and is more widely available in the US than in Canada. In both countries, many patients requested a prophylactic mastectomy after returning from a consult with a reconstructive surgeon.