Key clinical point: Patients with germline (g) BRCA1/2-associated primary breast cancer (BC), particularly those with g BRCA2 pathogenic mutations, faced a moderately increased risk of developing contralateral breast cancer (CBC) after receiving adjuvant radiotherapy.
Major finding: The risk for invasive and in situ CBC increased by 44% in patients with g BRCA1/2 mutations who did vs did not receive radiotherapy (adjusted hazard ratio [HR] 1.44; 95% CI 1.12-1.86), with the risk being even more prominent in g BRCA2 pathogenic variant carriers (adjusted HR 1.77; 95% CI 1.13-2.77).
Study details: Findings are from an analysis including 3602 patients with g BRCA1/2-associated primary BC from the prospective international BRCA1/2 Carrier Cohort Study, of whom 64% of patients received adjuvant radiotherapy.
Disclosures: This study did not receive any specific external funding. DG Evans reported ties with AstraZeneca and AmGen, K Kast declared ties with Roche Pharma AG, and J Simard declared holding patents related to BRCA1 and BRCA2.
Source: van Barele M et al. Contralateral breast cancer risk in irradiated breast cancer patients with a germline- BRCA1/2 pathogenic variant. J Natl Cancer Inst. 2023 (Jun 27). Doi: 10.1093/jnci/djad116