Mastectomy of Healthy Breast Does Not Extend Life

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A new study has shown that a preventative mastectomy of a healthy breast does not extend the life of breast cancer patients. Many women who have breast cancer choose to have a mastectomy of the breast that had the cancerous tumor, but some also have the healthy breast removed as well as a prophylactic measure. The idea is that removing breast tissue removes the opportunity for a breast cancer tumor to develop.

The recent study compared women who had a preventative mastectomy of a healthy breast and women who did not have a mastectomy and kept their healthy breast. Over a period of 20 years, the difference in the survival rates for the two groups was less than one percent. Having the healthy breast removed after an occurrence of breast cancer in the other breast did not extend survival times.

In this study, none of the women who participated had either of the breast cancer genes termed BRCA1 or BRCA2. This is a significant point. These genes have been well-established as conferring risk for the development of both breast cancer and ovarian cancer. The results from the recent study would not apply to cases of breast cancer where these genes are present.

The study was carried out at the University of Minnesota School of Medicine. Dr. Todd Tuttle, who is the chief of surgical oncology, was a lead researcher. Dr. Pamela Portschy, who is in the Department of Surgery at the University of Minnesota, was also a lead researcher. The study report was published in the Journal of the National Cancer Institute.

Data from a total of 100,000 women who had either stage I or stage II breast cancer were used in the study. The women were diagnosed with breast cancer at ages 40 years old, 50 years old or 60 years old. The data were obtained from the Surveillance, Epidemiology, and End Results (SEER) registry. A model was created that simulated survival outcomes. Whether the tumor was estrogen receptor positive or negative was considered. The results for women who had either estrogen receptor positive or estrogen receptor negative status were not different.

The current published statistics on breast cancer survival are about 98 percent of women with stage I breast cancer will survive for at least 10 years and about 90 percent will survive for about 20 years. For women with stage II breast cancer, the survival rate is 77 percent for 10 years and 58 percent for about 20 years.

No other factors, such as surgical complications, quality of life or level of fear when making the decision, were considered in the study. Fear has been shown to prompt some women into having a mastectomy of the healthy breast with 94 percent indicating they made this choice to boost survival despite only 18 percent of these women believing the mastectomy would actually extend life.

Reports are that if a women has breast cancer in one breast, the increased risk of developing cancer in the other breast is about four or five percent over 10 years. A key point, however, is the situation is dependent on whether there is a new breast tumor that develops or whether it is a second tumor derived from the original tumor.

Having a double mastectomy rather than a single mastectomy reportedly doubles the surgical risk and complications rates. The results from this latest study, showing that having a double mastectomy that includes a healthy breast, will likely be considered by many who are facing these tough decisions.

By Margaret Lutze

Journal of the National Cancer Institute
CBS News