By Karen Kaplan, Los Angeles Times/For the Booster Shots blog

September 23, 2011, 1:55 p.m.
Wanda Sykes has revealed to talk show host Ellen DeGeneres that she had a double mastectomy this year after doctors found evidence of early-stage breast cancer in her left breast.

As she explains on the program set to air on Monday, it all started with routine breast-reduction surgery. But then pathologists discovered that she had ductal carcinoma in situ, also known as DCIS.

“I was very, very lucky, because DCIS is basically stage zero cancer,” Sykes told DeGeneres.

The National Cancer Institute describes DCIS as a collection of abnormal cells inside the lining of a breast duct. “Many doctors don’t consider DCIS to be cancer,” according to this explainer, and some women would suffer no harm from it if left untreated. But in other cases, DCIS progresses and becomes invasive breast cancer – the dangerous kind. The problem is that there’s no way to predict which cases of DCIS are harmless and which will become life-threatening. However, experts agree that when caught at this early stage, the prognosis for women is “excellent.”

In Sykes’ case, she told DeGeneres that she didn’t want to take any chances, especially since cancer runs on her mother’s side of the family. Apparently, she did not reveal whether she has a mutation in her BRCA1 or BRCA2 genes, which increases a woman’s lifetime risk of breast cancer from 12% to about 60%.

“I had both breasts removed, because now I have zero chance of having breast cancer,” she told DeGeneres.

Well, not exactly. A double mastectomy certainly reduces one’s risk of breast cancer, but it doesn’t actually eliminate it, according to the Mayo Clinic:

Prophylactic mastectomy is highly effective. Studies show it reduces the risk of developing breast cancer by 90 percent in moderate- and high-risk women.

Although a prophylactic mastectomy significantly reduces your risk of breast cancer, it doesn't guarantee that you'll never develop the disease. Breast tissue is widely distributed on your chest wall. Sometimes breast tissue can be found in your armpit, above your collarbone or on the upper part of your abdominal wall, where it may not be detected at the time of your mastectomy. Breast tissue remaining in your body can still develop breast cancer, although the chances are slim.

If it seems like Sykes overreacted to her diagnosis, consider this study published this month in the American Journal of Surgery. Researchers from Wake Forest Baptist Medical Center wanted to figure out why more and more women with cancer in one breast are deciding to have their healthy breast removed as well. (The official medical name for this is contralateral prophylactic mastectomy, or CPM.)

The researchers looked at the medical records of 110 women who had surgical treatment for breast cancer. One-third of them had some kind of BRCA mutation that put them at high risk of developing another breast cancer. For these women, a bilateral mastectomy is usually recommended even if one breast is still cancer-free.

An additional 6% of women had a BRCA mutation that hasn’t been linked to breast cancer risk, and the remaining 61% had typical BRCA genes. Yet 37% of these women chose to have both breasts removed. The stage of breast cancer at the time of diagnosis did not appear to influence their decision – women with early-stage cancers were just as likely to opt for a double mastectomy as women with more aggressive tumors. Age didn’t make a difference either. In fact, the only demographic trait that was associated with an increased willingness to remove a healthy breast was marital status, with 44% (23 out of 52) of married women opting for the double mastectomy but only 8% (1 out of 13) of single women making the same choice.

“It is unclear if CPM in women who test negative for BRCA mutations will improve long-term survival,” the researchers concluded. “These findings warrant further prospective trials.”