Simple Summary
As the number of breast cancer patients achieving pathological complete response after neoadjuvant therapy increases, the choice regarding breast surgery extent becomes pivotal. This analysis from the EUSOMA database shows that breast-conserving surgery provides survival outcomes comparable to mastectomy in patients with pathological complete response. While axillary nodal involvement remains correlated with worse prognosis, mastectomy does not seem to improve survival. These findings support the efforts toward surgical de-escalation and reinforce breast-conserving surgery as a safe, evidence-based option for selected patients. In this context, current clinical practice should incorporate shared decision-making and avoid surgical overtreatment whenever feasible.
Abstract
Background: Optimal management of breast cancer (BC) patients with pathological complete response (pCR) after neoadjuvant therapy (NAT) remains debated. We performed a retrospective analysis to evaluate whether the extent of surgery influences survival outcomes in this patient population. Methods: Using the EUSOMA database, we retrospectively collected data of women with pCR after NAT, excluding those with BRCA1/2 mutations. The cohort was stratified by surgery type, i.e., breast-conserving surgery (BCS) or mastectomy. Relapse-free survival (RFS) and overall survival (OS) were compared using Cox regression. Results: Of 467 patients, 327 (70.0%) underwent BCS and 140 (30.0%) underwent mastectomy. Women treated with mastectomy were more likely to have multifocal tumors and advanced disease. After a median follow-up of 5.6 years, 7.3% of patients experienced BC recurrence. Axillary nodal involvement (cN+) and mastectomy were independently associated with recurrence, occurring in 11.4% of cN+ compared to 3.7% of cN0 patients (HR 3.02; 95% CI: 1.40–6.51; p = 0.005) and in 12.5% of mastectomy vs. 5.2% of BCS patients (HR 2.08; 95% CI: 1.05–4.11; p 0.035). cN+ patients also showed significantly higher mortality rates (9.4% vs. 1.6% of cN0; HR 6.16; 95%CI: 2.09–18.17; p= 0.001). However, surgery type did not impact OS. Conclusion: In this cohort of BC patients with pCR after NAT, BCS was not associated with a higher risk of recurrence compared with mastectomy. Baseline nodal involvement independently predicted recurrence and mortality; however, the type of surgery did not impact OS. These findings support BCS as a safe treatment option for this patient population.