Risk factors of locoregional relapse in locally advanced breast cancer treated with neoadjuvant chemotherapy following mastectomy and radiotherapy

We seek to investigate the prognostic factors that could possibly increase the locoregional recurrence of breast cancer patients who do not achieve pathological complete response after neoadjuvant chemotherapy, and to build a prognostic nomogram to predict patients' outcome. The retrospective analysis included 510 patients who had received neoadjuvant chemotherapy followed by surgery and radiotherapy. 62 locoregional events occurred after a median 61 months of follow-up. The five-year cumulative incidence of local recurrence and regional recurrence were 8.63% and 4.31%, respectively. Multivariate analysis revealed that positivity for ≥ 4 lymph nodes and Ki-67 index ≥ 14% were independent factors. According to our prognostic model, the 5-year locoregional free survival rates in the low, intermediate, and high-risk groups were 95.5%, 89.1%, and 67.1%, respectively (p < 0.001). Annual recurrence curves indicated that the relapse peak after mastectomy emerged in the first 1 year. Positivity for ≥ 4 lymph nodes and Ki-67 index ≥ 14% were independent factors for locoregional recurrence. This prognostic model has considerable clinical value in predicting locoregional recurrence, which could help clinicians to design appropriate locoregional treatment specifically and to perform surveillance individually.