There are limited data comparing the OncotypeDX© Recurrence Score (RS) among BRCA mutation carriers and patients with sporadic breast cancer.
To compare RS results among BRCA mutation carriers and patients with sporadic breast cancer in oestrogen receptor positive (ER+), human epidermal growth factor receptor-2 negative (HER2-) breast cancer.
A systematic review was performed in accordance with PRISMA and MOOSE guidelines. Retrospective cohort studies comparing RS in BRCA mutation carriers and cases of sporadic cancer were included. Dichotomous variables were pooled as odds ratios (ORs) and associated 95% confidence intervals (CIs) using the Mantel-Haenszel method.
Five studies involving 4286 patients were included with a mean age of 60 years (range 22-85). Overall, 7.8% were BRCA mutation carriers (333/4286). The mean RS was 18.0 (range 0-71), and the mean RS in BRCA carriers was 25 (range 10-71) versus 18.4 in cases of sporadic disease (range 0-62). Patients with sporadic cancers were more likely to have RS < 18 (OR 0.27, 95% CI 0.14-0.51, P = 0.010). BRCA mutation carriers were more likely to have RS 18-30 (OR 1.74, 95% CI 1.28-2.37, P  30 (OR 3.71, 95% CI 2.55-5.40, P < 0.001).
There is an increased likelihood of high-risk RS among patients with known germline BRCA mutations when compared to patients developing sporadic ER+/HER2-early breast cancer. This study offers insight into genomic testing results within BRCA mutation carriers which may be useful in counselling patients with BRCA mutations in future practice.

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