Clinical practice guidelines for the management of breast cancer in women with an identified BRCA1 or BRCA2 gene mutation or at high risk of a gene mutation (#19)
Ensuring currency of cancer clinical practice guidelines is essential for making timely, evidence-based information available to health professionals. Cancer Australia, with input from stakeholders, identified the management of breast cancer in women with an identified gene mutation or at high risk of a gene mutation, as a priority area requiring updated clinical guidance. Approximately 5-10% of breast cancers are due to germline mutations in genes including BRCA1 and BRCA2. It has been estimated that 58% of women with BRCA1 mutations and 28% of women with BRCA2 mutations are diagnosed with cancer before the age of 50 years.1
A multidisciplinary working group was formed to develop the evidence-based clinical practice guideline. The guideline was based on a systematic review of the evidence covering research questions on surgical management, adjuvant and neoadjuvant systemic therapies and surgical risk reducing strategies. The systematic search was limited to women with a germline BRCA1/2 mutation and a diagnosis of non-metastatic breast cancer.
The systematic review, which included 76 citations, has informed development of recommendations and practice points to guide management. Most of the included studies were observational studies, including prospective and retrospective cohort studies and case-control studies. No randomised trials were identified in the review.
The systematic review identified evidence that treatment with mastectomy compared to breast conserving treatment does not increase survival in women diagnosed with breast cancer with a BRCA1/2 mutation. There is evidence that contralateral risk-reducing mastectomy substantially decreases the risk of contralateral breast cancer and that risk-reducing salpingo-oophorectomy improves overall survival in women diagnosed with breast cancer with a BRCA1/2 mutation.
Cancer genetics is a rapidly emerging area and the guideline provides much needed updated clinical guidance to assist health professionals in making treatment recommendations for this unique group of women.
- Gage M, Wattendorf D and Henry LR. Translational advances regarding hereditary breast cancer syndromes. Journal of Surgical Oncology. 2012, 105(5):444-451.