PURPOSE: Genetic testing (GT) can identify individuals with pathogenic variants (PV) in breast cancer (BC) predisposition genes, who may consider contralateral risk-reducing mastectomy (CRRM). We report on CRRM rates in young women newly diagnosed with BC who received GT through a multidisciplinary clinic.
METHODS: Clinical data was reviewed for patients seen between November 2014 and June 2019. Patients with non-metastatic, unilateral BC diagnosed at age ≤45 and completed GT prior to surgery were included. Associations between surgical intervention and age, BC stage, family history, and GT results were evaluated.
RESULTS: Of the 194 patients, 30 (15.5%) had a PV in a BC predisposition gene (ATM , BRCA1, BRCA2, CHEK2, NBN, NF1), with 66.7% in BRCA1 or BRCA2. Of 164 (84.5%) uninformative results, 132 (68%) were negative and 32 (16.5%) were variants of uncertain significance (VUS). Overall, 67 (34.5%) had CRRM, including 25/30 (83.3%) PV carriers and 42/164 (25.6%) non-carriers. Only a positive test result was associated with CRRM (p < 0.01). For the 164 with uninformative results, CRRM was not associated with age (p = 0.23), a VUS, (p = 0.08), family history (p = 0.19), or BC stage (p = 0.10).
CONCLUSION: In this cohort of young women with BC, the identification of a PV in a BC predisposition gene was the only factor associated with the decision to pursue CRRM. Thus, incorporation of genetic services in the initial evaluation of young patients with a new BC could contribute to the surgical decision-making process.