Prospective and comparative evaluation of the toxicity of adjuvant concurrent chemoradiotherapy after neoadjuvant chemotherapy for breast cancer.

PURPOSE: The lack of pathologic breast cancer response to neoadjuvant chemotherapy (NCT), a negative prognostic factor, has prompted the addition of chemotherapy to adjuvant radiotherapy. This study aims to investigate prospectively the toxicities of adjuvant concurrent chemoradiotherapy versus radiotherapy alone. PATIENTS AND METHODS: Two groups of patients treated for breast cancer between 1997 and 2002 by NCT, surgery, and radiotherapy with or without concurrent chemotherapy, were matched on age, body mass index (BMI), treatment period, treated side, and surgery type. Late toxicity was prospectively evaluated according to the CTCAE v3.0. Acute toxicity was derived from the medical charts. RESULTS: A total of 52 patients were matched. Median follow-up was 10 years. Acute toxicity was higher in the chemoradiotherapy group compared with the radiotherapy alone group: 37% patients versus 10% experienced a grade 2/3 epithelitis (P=0.002); 48% versus 8% experienced a grade ≥1 mucositis (P=0.00001). Late toxicity was not significantly different in both univariate (51% vs. 49%; P=0.79) and multivariate analyses adjusted on the BMI (P=0.08). In univariate analysis, only the BMI tended to be predictive of toxicity (P=0.07). CONCLUSIONS: Concurrent chemoradiotherapy after NCT and surgery was associated with increased acute toxicity but not long-term toxicity. The efficacy of this therapeutic strategy should be evaluated to better define its indications.