PURPOSE: Triple-negative breast cancer (TNBC) is an aggressive subtype commonly treated with chemotherapy and radiotherapy, administered preoperatively as neoadjuvant chemotherapy (NACT) or postoperatively as adjuvant treatment (AT; defined here as adjuvant chemotherapy ACT with or without adjuvant radiotherapy ART). As NACT is increasingly favored, the relative survival outcomes of these approaches and the added benefit of postoperative therapy after NACT remain uncertain. This study aimed to assess their impact on survival. METHODS: In this nationwide registry-based cohort study, data for women diagnosed with cT1-2N0M0 TNBC in Sweden between 2007 and 2021 were retrieved from the Swedish National Quality Register for Breast Cancer. Survival outcomes for patients receiving NACT ± AT were compared with those receiving AT only. Propensity score matching (1:1) was performed, adjusting for age, clinical T-stage, and comorbidity. Overall survival (OS) and breast cancer-specific survival (BCSS) were estimated using Kaplan-Meier and Cox proportional hazards models. RESULTS: Of 3747 eligible patients, 711 received NACT ± AT and 3036 received AT alone. Median follow-up for BCSS was 3.61 years (IQR 2.37-5.50) for NACT and 6.95 years (IQR 4.36-9.62) for AT. After matching, 711 patients remained in each group. Both prior and post matching, 5-year OS and BCSS did not differ significantly between AT and NACT. These findings remained consistent after adjustment for potential confounders. CONCLUSION: OS and BCSS were similar between AT and NACT. These findings suggest that chemotherapy sequencing was not associated with a detectable survival difference, although treatment selection should be individualized and evaluated in the context of contemporary regimens.
Olsson et al. (Tue,) studied this question.