Nodal response to primary systemic therapy predicts prognosis of cN3c breast cancer patients receiving multimodality therapy

AIM: To investigate the survival outcomes, patterns and risks of recurrence in cN3c breast cancer patients after multimodality therapy, as well as the predictors of candidates for ipsilateral supraclavicular (SCV) area boosting. METHOD: Consecutive cN3c breast cancer patients from January 2009 to December 2020 were retrospectively reviewed. Based on nodal response to primary systemic therapy (PST), patients were categorized into three groups: clinical complete response (cCR) not achieved in SCV lymph nodal (SCLN, Group A), SCLN cCR but axillary node (ALN) did not achieve pathological complete response (pCR, Group B), cCR in SCLN and pCR in ALN (Group C). RESULTS: The median follow-up time was 32.7 months. The 5-year overall survival (OS) and recurrence-free survival (RFS) were 64.6% and 43.7% respectively. Multivariate analysis showed cumulative SCV dose and ypT stage, ALN response and SCV response to PST were significantly associated with OS and RFS respectively. Compared with Group A or B, Group C showed significantly improved 3 y-RFS (53.8% vs 73.6% vs 100%, p = 0.003), and the lowest rate of DM as first failure (37.9% vs 23.5% vs 0%, p = 0.010). In Group A, the 3 y-OS for patients receiving the cumulative SCV dose of ≥60 Gy versus <60 Gy was 78.0% versus 57.3% (p = 0.029). CONCLUSION: Nodal response to PST is an independent prognostic factor for survival and pattern of failure. A cumulative SCV dose of ≥60 Gy is positively associated with improved OS, especially in Group A. Our data supports the perspective of optimizing radiotherapeutic strategy based on nodal response.