Some women, upon learning they have cancer in a breast, will elect to have the second, healthy breast removed, out of fear that the disease will wind up in that other breast sooner or later.

This decision has met with criticism, including by doctors, who say it doesn’t improve survival odds much. The latest study comes from the Dana-Farber Cancer Institute.

In women who do not have a genetic predisposition to breast cancer, the odds of the disease striking the non-removed healthy breast is 2 to 4 percent, says this study.

To me, that sounds like a pretty darned good reason to have the healthy breast removed. I can’t blame a woman for refusing to live her life constantly wondering if she’s in that 2 to 4 percent group.

My cousin decided to have her healthy breast removed after being diagnosed with this disease. This decision is called contralateral prophylactic mastectomy (CPM). Otherwise, she’d be incessantly waiting for that other shoe to drop.

The Dana-Farber study details appear in the Sept. 17, 2013 Annals of Internal Medicine. The paper says that CPM has negligible impact on survival rates for women with non-genetic breast cancer.

How could this be when my cousin eliminated herself from that 2 to 4 percent group?

Though it’s possible that micrometasteses can be missed in what appears to be early stage breast cancer  —  the mets having already settled in some distant part of the body, that will eventually rear their ugly head in a woman who has CPM  —  what if a woman who has CPM doesn’t already have the micrometasteses? How could CPM not have a respectable positive impact on survival?

“An increasing percentage of women treated for early-stage breast cancer are choosing to have CPM,” says the study’s lead author, Shoshana Rosenberg, ScD, MPH.

She notes that many women have an unrealistic perception of CPM’s benefits and risks.

My cousin has not had a recurrence of her disease; her CPM was about 12 years ago. Who’s to say that, had she not had the CPM due to vanity, she wouldn’t have had a recurrence in that other breast eventually  —  maybe even two years out from the initial diagnosis? Vanity was never on her mind.

The study also says that many of the women underestimated the extent of CPM’s side effects. Many subjects reported that CPM’s effect on their appearance was worse than expected. Alarmingly, 42 percent of the participants reported that CPM had damaged their sense of sexuality.

If a woman puts health and survival far ahead of vanity, and derives her sense of sexuality from the most important sex organ of all, the brain, then she should have a right to choose CPM without having to get the third degree from her medical team or anyone else.

A woman should not have to go through an Act of Congress to have her healthy breast removed when the other one has cancer.