In recent years, research has found that more and more women are opting for a double mastectomy. Now, a study published in JAMA Surgery finds that the reason behind this increase is driven in part by the surgeons performing the procedure—even if it’s not medically necessary.

With many other treatment options available, doctors generally discourage women at average risk to undergo a contralateral prophylactic mastectomy, also known as CPM. A CPM involves removing both breasts when only one breast has cancer. If the woman has a higher risk gene, like BRCA, then a doctor will typically recommend a CPM.

Time reports that the number of women choosing to remove both breasts has increased “nearly six fold from 1998 to 2011.” This is also seen mostly with younger women with early stages of cancer in one breast and who have no genetic risk factors.

This new study shows that there are many reasons for the increasing demand for CPM. However, it notably mentions that 20 percent of the accountability in variations is due to the woman’s doctor.

Researchers surveyed 5,080 women at average risk with early-stage breast cancer, along with 377 of their surgeons. They found that doctors largely agreed initially to recommend breast conserving surgery over CPM. However, that didn’t necessarily match up with what was eventually performed.

They found that if a woman went to a surgeon who was hesitant to perform a CPM, she had only a four percent chance of undergoing it. If she went to what researchers referred to as a surgeon open to performing a CPM, she had a 34 percent chance of having both breasts removed, even with their initial reluctance.

The surgeons explained that their reasons for offering a CMP was “to give patients a peace of mind,” and “avoid patient conflict.” These choices were in no way linked to increase survival rates or decrease recurrence.

Old Lyme, CT, plastic surgeon Vinod Pathy, MD, says, “Like other colleagues of mine, I have seen an increase in contralateral prophylactic mastectomies in certain populations in recent years in my practice, particularly in the younger population.” He also notes that while the study is interesting, it is not surprising that surgeons have an influence on the treatment offered to the patient based on the doctor’s bias.

“It is clear from the recent study that medicine and surgery are just as much art as they are science at times,” Dr. Pathy says. “Regarding a bilateral mastectomy, it is important for us as surgeons to gather not only the typical scientific data regarding survival rates and recommendations by our respective societies and governing bodies, but also to listen to our patients, impart our expertise in general, but do our best to remove some of our biases one way or another in providing the best options for care.”

But that’s not to say that the decision is based on just one factor. “Because breast oncologic care should be a true team approach, the best care for the patient ultimately is brought about by discussions with the entire team,” adds Dr. Pathy. This team includes the breast surgeon, oncologist, radiologist, possibly radiation oncologist, pathologist, medical physician, and reconstructive surgeon and other ancillary services.

If you do have to go through breast cancer treatment, just be sure to keep an open dialogue with your doctors to determine the best options for your treatment and care.