Long-term outcome of accelerated partial breast irradiation using a multilumen balloon applicator in a patient with...

Accelerated partial breast irradiation is now an accepted component of breast-conserving therapy. However, data regarding long-term outcomes of patients treated with multilumen catheter systems who have existing breast implants are limited.

We report the treatment and outcome of our patient who had existing bilateral silicone subpectoral implants at the time of presentation. Ultrasound-guided core needle biopsy of the right breast showed infiltrating mucinous carcinoma. Right breast lumpectomy revealed an 8 mm area of infiltrating ductal carcinoma with mucinous features and nuclear grade 1. A 4-5 cm Contura (Bard Biopsy Systems, Tempe, AZ) device was placed, and she was treated over the course of 5 days twice daily to a dose of 34 Gy using a high-dose-rate iridium-192 source.

The planning target volume for evaluation was 73.9 cc. The percentage of the planning target volume for evaluation receiving 90%, 95%, and 100% of the prescribed dose was 99.9%, 99.3%, and 97.8%, respectively. The total implant volume was 234.5 cc and received a mean dose of 15.4 Gy and a maximum dose of 72.8 Gy. The percentage of implant volume receiving 50%, 75%, 100%, and 200% of the prescribed dose was 31.1%, 16.5%, 8.6%, 2.0%, and 0%, respectively. Maximum skin dose was 97% of the prescribed dose. With a followup of nearly 5 years, she continues to be cancer free with minimal late toxicities and good to excellent cosmetic outcome.

Accelerated partial breast irradiation using a multilumen balloon applicator in patients with existing breast implants can safely be performed with excellent long-term cosmetic outcome. Further studies are needed to establish the absolute dosimetric tolerance of breast implants.