[Prospective monocentric study of the toxicity and the efficacy of concurrent trastuzumab and radiotherapy].

PURPOSE: Prospective monocentric study of the toxicities related to concurrent administration of trastuzumab to breast radiotherapy.

PATIENTS AND METHODS: One hundred and seventy-three patients were treated between June 2003 and March 2009 by concurrent trastuzumab with normofractionated radiotherapy. Trastuzumab was delivered every 3 weeks (8mg/kg in the first infusion then 6mg/kg) during a median time of 12 months (2-62). Left ventricular ejection fraction was assessed by echocardiography or cardiac scintigraphy at baseline, before and after radiotherapy, every 3 months for 1 year and annually. A left ventricular ejection fraction strictly lower than 55% was considered as altered. All toxicities were evaluated using Common Terminology Criteria for Adverse Effects version 3.0.

RESULTS: Median follow-up was 52 months (17-88). Median age was 52 years (25-83). One hundred and thirty-four patients (77.5%) received radiotherapy to the internal mammary chain. Acute grade 1, 2 and 3 epithelitis was described in 132 (76.3%), 32 (18.5%) and six patients (3.4%), respectively. At 23 months, grade 1 and 2 fibrosis was observed in 31 and eight patients, respectively (18.8 and 4.6%). Left ventricular ejection fraction remained normal for 159 patients (91.9%) before radiotherapy. Among them, 18 (11.3%) experienced a left ventricular ejection fraction alteration, eight (5.0%) at the completion of radiotherapy. Congestive heart failure occurred in one patient (0.6%).

CONCLUSIONS: Toxicities related to the association of trastuzumab to breast radiotherapy were mild. Further follow-up is warranted.