(Reuters Health) - Breast cancer surgeons play a big role in deciding whether women with early-stage breast cancer undergo a controversial operation to have both breasts removed, even when cancer is found in only one, a new study shows.

The decision to go ahead with the procedure may depend more on the surgeon’s preferences than on the patient’s, researchers say.

“The majority of patients strongly defer to their surgeons - perhaps because of the complexity of the treatment choices and clinical information,” Dr. Steven Katz of the University of Michigan in Ann Arbor said in an email to Reuters Health.

Katz and colleagues studied survey responses from women diagnosed with early-stage breast cancer in one breast. Among the 3,353 women (mean age, 62) who participated in the survey, 16% had the other breast removed as a preventive measure - a procedure called contralateral prophylactic mastectomy (CPM).

Researchers also surveyed 349 of the patients’ surgeons, to gauge their attitudes toward CPM versus breast-conserving surgery, which involves removing just the cancerous tissue, or surgery to remove only the affected breast.

Medical guidelines generally recommend against CPM because it doesn’t improve survival – except possibly for women with certain genetic mutations that increase their risk for breast cancer and other malignancies - and it increases the risk for surgical complications.

Surgeons were given a hypothetical case - a woman with a normal mammogram, no family history of breast cancer, and a small mass in one breast - and asked what treatment they would recommend. They were also asked if they would perform CPM if a woman requested it.

It turned out that surgeons’ attitudes were strongly linked with whether or not their patients received CPM, according to the report published in JAMA Surgery.

When surgeons heavily favored breast-conserving surgery and were most reluctant to perform CPM, only 4 percent of their patients actually received CPM.

In contrast, 34 percent of women whose surgeons didn’t favor breast conservation and who were most willing to do CPM had the procedure done.

The most common reasons surgeons gave for performing CPM, according to the survey, were to give patients peace of mind, to avoid patient conflict and to improve cosmetic outcomes. The least frequent reasons were to avoid losing the patient or to improve survival.

Katz offered tips for women with early-stage breast cancer who want to explore all of their treatment options:

1- Ask your surgeon’s opinion about the best options and why, and discuss benefits and harms.

2- Bring someone with you on the first visit to take notes and help with questions.

3- Ask the surgeon to briefly summarize his or her recommendations while you record them on your cell phone so you can review them later. Even if you feel you’ve made a decision on the first visit, go back for a second visit or discuss again by phone before finalizing.

“Both patients and physicians have inherent biases when discussing the options for breast cancer surgical therapy,” Dr. Julie Margenthaler of the University of Washington School of Medicine in St. Louis told Reuters Health in an email.

The treatment decision “can be very difficult and is a very personal one,” said Margenthaler, coauthor of an editorial that was published along with the study. Discuss options thoroughly, she advises, so you can make “an informed decision that meets your goals and values.”

Katz added, “Surgeons want to get this right with patients, and realize it’s not just only about surgery - it’s about all the treatments on the table, including radiation, endocrine therapy, chemotherapy.”

“Slow the decision process down if you need to,” he said. “If you’re uncertain, a good surgeon will be happy to arrange a second opinion.”

SOURCE: bit.ly/2y3OIEs and bit.ly/2y4bRXn JAMA Surgery, online September 13, 2017.