Prophylactic Mastectomy—Yes of No?
Breast cancer is a very common disease, with nearly 300,000 new cases in the United States annually. According to the American Cancer Society, breast cancer is the second leading cause of cancer death among women. For many women, more than just a lumpectomy is needed to ensure that malignant cells are all removed. And plenty of patients requiring a mastectomy for one breast consider the removal of the other breast as well even if no signs of cancer have been found there. It's a natural reaction to want to eliminate any possibility of having to go through a second round of treatment or risk dying of the disease, but new research suggests that prophylactic mastectomy may not offer any measurable health benefit.
The study, which was conducted at the University of Minnesota School of Medicine in Duluth, found that survival rates for breast cancer patients are not significantly improved when their healthy breast is removed for prophylactic purposes.1 The subjects were more than 100,000 women who had stage I or stage II breast cancer. The researchers followed them for a 20-year period to track survival in both those who had undergone a mastectomy preventively and those who had not. They determined that the survival benefit over the course of 20 years was less than one percent higher for the women who had their healthy breast removed than for the women who did not opt for removal.
In life expectancy terms, the outcome was a very slight increase for those who had the preventive mastectomy, with a boost that ranged from one to seven months. However, that modest bump was spread across the decades covered in the study, decreasing its impact significantly. It was the younger patients diagnosed at stage I who appeared to benefit slightly more from a prophylactic mastectomy, especially if they had estrogen receptor-negative breast cancer. Stage I refers to the fact that it has not spread beyond the breast except perhaps minimally to the lymph nodes. Estrogen receptor-negative breast cancer is not stimulated by estrogen circulating through tissues. Estrogen receptor-positive breast cancers are far more common, though. Yet even for these participants, the results showed a statistical difference of less than one percent in survival rate between the two groups of women.
One major caveat to the research is that women with BRCA-1 and BRCA-2 genes were not included. These genes contain mutations that have been found to greatly elevate the risk of developing not only breast, but also ovarian cancer in carriers. In fact, a 1999 study through the Cancer Research Campaign in Cambridge, United Kingdom found that the BRCA-1 and BRCA-2 genes together are responsible for between 20 and 25 percent of hereditary breast cancers.2 Because of this apparently greater risk, many women who are BRCA positive decide to have one or both healthy breasts removed and/or a prophylactic oophorectomy to remove the ovaries. It is this fear of finding a malignancy or having a recurrence that drives so many women to be willing to remove a breast with no sign of cancer.
It is certainly a difficult decision for anyone to have to make. Even if the preventive mastectomy will be performed during the same procedure as the removal of the diseased breast, it still increases surgical risk as the time under anesthesia is extended and the chance of developing complications such as infection and bleeding is higher as well. If the results of this study are correct, it would appear that it may not be worth the additional risks for an increase in survival rate of less than one percent, with the possible exception of those who have tested positive for BRCA genes. But even here, without a family history of breast cancer (which might be due to shared diet and/or environmental factors), the differences between those women who test positive for the BRCA genes and those who don't is only 5%.
Ultimately, the best-case scenario is to never have a breast cancer diagnosis so you will never need to contemplate a prophylactic mastectomy. Of course, it is impossible to guarantee prevention as breast cancer strikes one in eight women at some point in their lives and there are a complex array of both environmental and genetic factors involved. But there are certainly steps we can take to lower the chance of developing the disease. Maintaining a healthy weight and eating a nutritious diet rich in fruits and vegetables have both been shown to help prevent breast cancer, while consumption of alcohol is associated with an increased risk. Balancing your hormones is also important. And a 2012 study at the University of North Carolina at Chapel Hill found that increasing physical activity levels can cut breast cancer risk.3 A few moderations to your lifestyle may ultimately make a very big difference.
- 1. Doheny, Kathleen. "Preventive mastectomy does little to extend life of breast cancer patients." CBS News. 16 July 2014. Accessed 23 July 2014. http://www.cbsnews.com/news/removing-healthy-breast-has-little-benefit-to-breast-cancer-patients
- 2. Easton, Douglas F. "How many more breast cancer predisposition genes are there?" Breast Cancer Research. 23 August 1999. Accessed 24 July 2014. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC138504
- 3. McCullough, Lauren E.; et al. "Fat or fit: The joint effects of physical activity, weight gain, and body size on breast cancer risk." Cancer. 25 June 2012. Accessed 24 July 2014. http://onlinelibrary.wiley.com/doi/10.1002/cncr.27433/abstract