Initial clinical experience with the Strut-Adjusted Volume Implant brachytherapy applicator for accelerated partial breast irradiation

Abstract

Purpose Accelerated partial breast irradiation is becoming increasingly popular. The Cianna single-entry high-dose-rate applicator, Strut-Adjusted Volume Implant (SAVI, Cianna Medical, Aliso Viejo, CA), contains peripheral struts allowing greater planning flexibility for small-breasted women, technically easier insertion, and normal tissue exposure minimization. This study evaluates early clinical experience. Methods and Materials Thirty patients treated with the SAVI with a median followup of 12 months were evaluated. The median age was 59.5. Tumor size averaged 0.9 cm. Fifteen cancers were ductal carcinoma in situ (50%), 1 was invasive lobular (3.3%), 4 were tubular (6.7%), and the rest infiltrating ductal (40%). Most of them were estrogen receptor (ER) positive (90%). Nine women (30%) were premenopausal. Results Dosimetry was outstanding with median V90, V150, and V200 of 96.2%, 24.8, and 12.8 cc. There were no symptomatic seromas, and one report of asymptomatic fat necrosis seen on mammogram at 1 year. In patients who had skin spacing of less than 1 cm, the median skin dose was 245 cGy/fraction. The median rib and lung dose per fraction for those patients with either structure less than 1 cm was 340 and 255 cGy (75% of prescribed dose), respectively. There have been no local recurrences to date. Conclusions Early clinical experience with the SAVI demonstrates the ease of placement of a single-entry brachytherapy device combined with the increased dose modulation of interstitial brachytherapy. Dose to normal structures has remained exceedingly low. Almost half of evaluated patients were not candidates for other single-entry brachytherapy devices because of skin spacing or breast size, demonstrating an expansion of candidates for single-entry partial breast brachytherapy.