An increasing number of women with cancer affecting one breast (unilateral) are now opting for the removal of both breasts (bilateral mastectomy), as opposed to a lumpectomy and radiation to remove the tumor. A third surgical option that some women choose to undergo is a unilateral mastectomy. Radiation is not needed after a unilateral mastectomy.
But does a bilateral mastectomy improve survival compared to a lumpectomy with radiation?
No, it doesn’t, according to a recent observational study published in the Journal of the American Medical Association. It found that there is no benefit to undergoing a bilateral mastectomy when compared to a lumpectomy with radiation, but that a unilateral mastectomy, without radiation, actually has worse results. The study used data from 189,734 newly diagnosed women with stages 0-III unilateral breast cancer in California from 1998 through 2011. The data, taken from the California Cancer Registry, showed an increasing rate of bilateral mastectomies, rising from 2% in 1998 to 12.3% in 2011. The greatest increase for women undergoing bilateral mastectomies for breast cancer in one breast was in women less than 40 years old at the time of diagnosis. We don’t know why this surge in bilateral mastectomies occurred, but the results from the study provide us with information regarding surgical treatment options for patients with breast cancer.
Ten year mortality rates were 18.8% for bilateral mastectomy, 16.8% for lumpectomy surgery with radiation, and 20.1% for unilateral mastectomy without radiation. Patients who had unilateral mastectomies experienced significantly higher mortality compared to the other two treatment options. The mortality rates for bilateral mastectomy and lumpectomy with radiation were not significantly different.
Patients have a choice whether or not to undergo a bilateral mastectomy for unilateral breast cancer, and there are many variables that can influence a patient’s decision for treatment. However, there are risks and complications that go along with a bilateral mastectomy, including bleeding, infections, and the potentially negative effects on psychological well-being. A lumpectomy has a somewhat lower level of risk, although the radiation performed after such surgery has its own risks. However, many patients are misinformed, and believe that once they’ve had a bilateral mastectomy, there is absolutely no chance of their facing breast cancer again. This option then, provides them with a greater sense of protection than a lumpectomy with radiation. In reality, however, there is no guarantee that all breast tissue will be completely removed during a mastectomy, and any remaining tissue could at some point become cancerous. This may help explain why a bilateral mastectomy does not improve survival when compared with a lumpectomy and radiation.
There are certain situations in which prophylactic bilateral mastectomies are sometimes recommended. Previous studies have shown that bilateral mastectomies reduce the risk of breast cancer by at least 95% in cases where women possess the BRCA 1/2 gene mutation, which puts patients at a higher risk for breast cancer. However, the majority of women opting for a bilateral mastectomy do not have the mutation, which is why the increased rate of bilateral mastectomies is perplexing to doctors.
Socioeconomic status may be a driving factor for patients choosing different surgical options. In this study, patients undergoing a double mastectomy were mostly non-Hispanic whites, with private insurance, and receiving care at a National Cancer Institute-designated cancer center. Unilateral mastectomy was mostly done in ethnic minorities (Asian, Hispanic) and patients with public/Medicaid insurance. These patients may have more logistical difficulties in attending the 6 weeks of daily radiation that often follows breast-conserving surgery, which could improve their survival rates over having unilateral mastectomies. It is possible, of course, that these patients experienced worse survival due to other factors related to socioeconomic factors. However, the researchers attempted to control for this possibility with statistical analysis, and found that it did not change their results.
Even though the study used data of nearly two hundred thousand breast cancer patients, it lacked data on family cancer history, genetic testing, and comorbidities, which certainly can influence surgical decisions. Future research that includes this information is needed in order to further our understanding of these treatment options.
Nevertheless, the results of this study provide us with valuable information for newly diagnosed breast cancer patients. Patients should be educated about treatment options and their potential risks. Women need to be aware of the fact that undergoing a more invasive surgery such as a bilateral mastectomy may not be necessary, as there may very well be no survival advantage compared to having a lumpectomy.