Investigators have found that risk-reducing mastectomy decreases the risk of receiving a breast cancer diagnosis and the likelihood of mortality in female patients with BRCA1 or BRCA2 genetic variants, according to a recent study published by Metcalfe et al in the British Journal of Cancer.
Background
Female patients who have an inherited BRCA1 or BRCA2 genetic variants have an 80% risk of developing breast cancer over the course of their lifetimes. Research has shown that a risk-reducing mastectomy—one of the most effective strategies for preventing breast cancer in female patients with this risk profile—may reduce the risk of breast cancer by 90%. In Canada, 30% of female patients with pathogenic variants tend to opt for this surgery.
However, to date, there has been only one previous study exploring the impact of risk-reducing mastectomy on mortality and quantifying the benefits in this patient population.
“The decision to have a risk-reducing mastectomy is often difficult for a [patient] to make, and the more evidence we are able to provide them with when they are making that decision, the more informed their care plan will be,” explained lead study author Kelly Metcalfe, RN, PhD, FCAHS, FAAN, of the Lawrence Bloomberg Faculty of Nursing and a senior scientist at the Women’s College Research Institute.
Study Methods and Results
In the recent pseudorandomized study, the investigators examined how risk-reducing mastectomy may affect the rate of mortality in 1,600 female patients with pathogenic BRCA1 or BRCA2 variants but no breast cancer diagnoses. They noted that about 50% of the patients underwent risk-reducing mastectomy.
After a follow-up of 6 years, the investigators discovered 20 cases of breast cancer and two deaths in the risk-reducing mastectomy group, and 100 cases of breast cancer and seven deaths in the control group. Additionally, risk-reducing mastectomy decreased the risk of breast cancer incidence by 80%, and the risk of dying from breast cancer within 15 years of the procedure was less than 1%.
Conclusions
“Although there wasn’t a significant difference in deaths between the two groups in this study, we know that a risk-reducing mastectomy significantly reduces the risk of ever developing breast cancer,” underscored Dr. Metcalfe.
The investigators indicated that following-up with the patients involved in the study for longer periods of time could generate more evidence to assess the true post–risk-reducing mastectomy mortality rate and highlight the benefits associated with this type of procedure.
“Right now, we have good screening in place for breast cancer, including breast [magnetic resonance imaging], so surgery is only offered as an option, not a recommendation. [Nonetheless], with more studies being conducted to assess [patients'] trajectory and risk factors following [risk-reducing mastectomy], we will know whether these guidelines need to be changed in the future,” concluded Dr. Metcalfe.
Disclosure: For full disclosures of the study authors, visit nature.com.
