Impact of multifocal or multicentric disease on local recurrence and survival in breast cancer patients with or without BRCA1/2 variants.

PURPOSE: Multifocal or multicentric (MFMC) breast cancer is mainly focused on breast cancer patients with unknown BRCA status, the incidence and clinical relevance of MFMC disease in BRCA1/2 carriers is less explored to date. Our study was to investigate the incidence of MFMC disease in BRCA1/2 carriers and whether MFMC disease influences local recurrence and clinical outcomes.

METHODS

In this retrospective study, 479 breast cancer patients with BRCA1/2 variants and 1437 age-matched noncarriers were enrolled and patients received either breast-conserving therapy (BCT) or mastectomy with or without radiotherapy.

RESULTS

The rates of MFMC disease in BRCA1 and BRCA2 carriers, and noncarriers were 33.0% (61 of 185), 37.4% (110 of 294), and 31.2% (449 of 1437), respectively. MFMC disease in BRCA2 carriers was significantly higher than that in noncarriers (P = 0.039). After a median follow-up of 8.1 years, among patients treated with BCT, BRCA2 carriers with MFMC disease experienced a significantly higher rate of ipsilateral breast tumor recurrence (IBTR) than those with unifocal disease (16.7% vs 4.1%, P = 0.044). Moreover, BRCA2 carriers with MFMC disease had a significantly worse RFS (unadjusted hazard ratio [HR], 3.65 [95% CI 1.40-9.52]; P = 0.008), DRFS (unadjusted HR, 3.07 [95% CI 1.07-8.80]; P = 0.037), and OS (unadjusted HR, 4.96 [95% CI 1.18-20.02]; P = 0.029) than those with unifocal disease when treated with BCT.

CONCLUSION

MFMC breast cancer is more common in BRCA2 carriers, and BRCA2 carriers with MFMC disease treated with BCT exhibit a higher rate of IBTR and may have a poor survival.