Residual Primary Breast Cancer After Chemotherapy: Assessment of Recurrence and Survival

Introduction The presence of residual breast cancer after neoadjuvant chemotherapy can influence the rate of distant recurrence. Objective To identify clinical and tumoral risk factors predicting recurrence, and to evaluate their impact on distant recurrence-free survival (DRFS), in patients with stage III breast cancer who did not achieve a pathological complete response (non-pCR) after neoadjuvant chemotherapy Material and methods This retrospective study evaluated the association between risk factors and recurrence in patients who did not achieve a pathological complete response using relative risk. Five-year distant recurrence-free survival was calculated for three risk groups: low-risk, intermediate-risk, and high-risk. The discriminative ability for predicting recurrence was assessed using receiver operating characteristic methodology. Two Cox regression analyses were performed to identify independent predictors of relapse. Results Residual tumor was present in 69.8% (88/126) of patients, with 47 total recurrences. Significant risk factors included clinical stage IIIB, grade 3 tumors, and luminal B and HER2+ subtypes, with relative risks (RRs) of 3.5 (95% CI: 1.6-7.5), 3.7 (95% CI: 1.7-8), 3.4 (95% CI: 1.3-8.6), and 4.2 (95% CI: 1.1-15), respectively. Recurrence rates for the low-risk, intermediate-risk, and high-risk groups were 22% (10/45), 36% (19/53), and 64% (18/28), respectively, with corresponding five-year distant recurrence-free survival rates of 67% (95% CI: 43-83%), 61% (95% CI: 46-73%), and 36% (95% CI: 18-54%). The positive likelihood ratios were 0.38 for the low-risk group, 0.71 for the intermediate-risk group, and 2.94 for the high-risk group. Cox regression analysis showed that the intermediate-risk and high-risk groups had an increased risk for recurrence of 3.3 (95% CI: 1.2-9) and 5.4 (95% CI: 1.9-15) times, respectively, compared to the low-risk group. Conclusions This staging that includes a clinical and tumoral characteristics scale facilitates the early optimization of subsequent systemic treatments, allowing for therapeutic adjustments prior to the development of clinical metastasis.