Patterns of Distant Failure by Intrinsic Breast Cancer Subtype in Premenopausal Women Treated With Neoadjuvant Chemotherapy.

PURPOSE: To identify patterns of distant failure (DF) in premenopausal women receiving neoadjuvant chemotherapy (NAC) for breast cancer.

PATIENTS AND METHODS: Premenopausal patients treated with NAC between 2005 and 2015 at a single institution were retrospectively reviewed. Timing and location of local, regional, and distant metastases were described. Predictors for DF and overall survival (OS) were analyzed.

RESULTS: Of 225 patients, there were 24 (10.7%) local, 30 (13.3%) regional, and 63 (28.0%) distant recurrences. Cumulative incidence of DF was higher in patients younger than age 40 (P = .01), in those with residual tumor size > 2 cm (P < .0001), in those with positive lymph nodes after NAC (P = .0003), and in those without pathologic complete response (P < .0001). Cumulative incidence of brain metastases was most common in patients with human epidermal growth factor receptor 2 (HER2)-positive disease (P = .05). Time from development of metastatic disease to death varied by breast cancer subtype (P = .019), as did 5-year OS (P = .024). Women with HER2-positive and triple-negative disease had the highest incidence of brain metastases and the shortest time from development of metastases to death. On multivariable analysis, luminal B subtype (P = .025), pathologic complete response (P = .0014), young age (P = .0008), lack of hormone therapy (P < .0001), lymphovascular space involvement (P < .0001), and pathologic size of the primary tumor (P < .0001) were all significant predictors for DF.

CONCLUSION: Patterns of DF after NAC in premenopausal women vary by breast cancer subtype, with DF more common than locoregional failure. Young age remains an independent poor prognostic factor, and OS differs by breast cancer subtype.