Purpose: We compared patients undergoing partial breast irradiation (PBI) with the MammoSite applicator (Cytyc Corp., Marlborough, MA) to a similar group of patients who underwent whole breast irradiation with external beam radiotherapy.
Methods and materials: Stage 0-IIA breast cancer patients satisfying American Brachytherapy Society selection criteria and receiving accelerated PBI with the MammoSite system (n=100) were compared for toxicities with similarly staged patients receiving whole breast irradiation using tangential portals (n=100). The MammoSite applicator treatment was prescribed to a total dose of 34 Gy. External beam doses generally ranged from 60 to 66 Gy.
Results: Based on common toxicity criteria scores for acute toxicities, MammoSite patients experienced less cutaneous toxicity, fatigue, and breast pain and had higher Karnofsky performance status scores during the acute period than external beam patients but experienced more seroma pain during followup. These results were both statistically significant and clinically meaningful.
Conclusions: In our institutional experience, PBI using the MammoSite applicator produces less acute toxicity than external beam radiotherapy of the whole breast but is associated with an increased incidence of seroma pain. The rate of disease recurrence in both cohorts was low.
(c) 2010 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.