A systematic review of international guidelines and recommendations for the genetic screening, diagnosis, genetic counseling, and treatment of BRCA-mutated breast cancer

Carol Forbes,¹ Debra Fayter,¹ Shelley de Kock,² Ruben GW Quek<sup>3

1</sup>Department of Reviews, Kleijnen Systematic Reviews Ltd, Escrick, York YO19 6FD, UK; ²Department of Information, Kleijnen Systematic Reviews Ltd, Escrick, York YO19 6FD, UK; ³Health Economics and Outcomes Research, Pfizer Inc., San Francisco, CA 94105, USA

Purpose: To conduct a systematic review of international guidelines on screening and management of patients with BRCA-mutated breast cancer (BC).
Methods: Major electronic databases (MEDLINE and Embase; N=8) and gray literature sources were searched (January 2007 to February 2018). Latest guideline recommendations on genetic screening, counseling, and BC treatment of BRCA mutation carriers were summarized. Guidelines specific to germline BRCA (gBRCA) mutation were captured where available.
Results: A total of 3,775 records were retrieved and 32 guidelines were included; Europe (n=16), USA (n=11), Canada (n=3), Australia (n=1), and Japan (n=1) were included. Across and within guidelines, genetic counseling was recommended at multiple points in the care pathway, though the format was not always clearly defined. US guidelines emphasized that BRCA mutation testing should occur after specialized genetic counseling; other European guidelines are less prescriptive. BRCA testing eligibility criteria differed, with some guidelines being less restrictive; US National Comprehensive Cancer Network (NCCN) BC guidelines specified that HER2-negative BC patients eligible for single-agent therapy are eligible for gBRCA testing. Fast-track BRCA testing is recommended in the Netherlands if treatment choice will affect survival, but in the UK only as part of clinical trials. More recent European (European School of Oncology–European Society for Medical Oncology 3rd International Consensus Guidelines for Breast Cancer in Young Women 2017, Arbeitsgemeinschaft Gynäkologische Onkologie 2017 in Germany) and US (NCCN) guidelines have updated recommendations regarding gBRCA-targeted poly(ADP-ribose) polymerase (PARP) inhibitor therapy in BC.
Conclusion: Regional and organizational guidelines differ for genetic screening, counseling, and treatment of patients with BRCA-mutated BC. Guideline harmonization would optimize identification and management of these patients.

Keywords: BRCA1, BRCA2, guidelines, systematic review, chemotherapy, PARP inhibitor