A single-institution study of intraoperative radiation therapy (IORT) using electronic brachytherapy

Objective Two prospective randomized trials, TARGIT-A and ELIOT, have shown intraoperative radiation (IORT) to be safe and well-tolerated in low-risk patients. Electronic IORT with the Xoft Axxent system has few long-term reported results. Materials/methods A total of 100 patients (101 tumors) were treated with partial mastectomy and intraoperative brachytherapy. Electronic brachytherapy via IORT was utilized to deliver 20 Gy to the balloon surface in a single fraction prior to completion of surgery. Necessity of additional intervention with surgery or radiation was noted, as was the presence of clinical seroma and tumor recurrence. Patients were followed at regular intervals for at least 5 years. Results Patients ranged in age from 41 to 83, with a median age of 66. Out of the 101 tumors treated, T-staging consisted of 28.7% Tis, 2.0% T1mi, 11.9% T1a, 23.8% T1b, 30.7% T1c, and 3.0% T2. At a median follow up of 3.8 years, there have been two recurrences. Eighteen patients required additional surgery or radiation. Patients classified as "suitable" by the accelerated partial breast irradiation suitability criteria were less likely to require re-excision (suitable: 1.6%, cautionary: 22.6%, unsuitable: 87.5%, P < 0.001), but no less likely to require additional whole breast irradiation. Symptomatic seromas were noted in 15% of patients. Conclusion IORT is a convenient and well-tolerated treatment option for the appropriately selected woman undergoing partial breast irradiation. Rates of seroma formation are similar to rates reported for multiple fraction catheter-based systems.