PP36 Presentation Time: 11:40 AM: Five Day Accelerated Partial Breast Irradiation (APBI) Using Stereotactic Body Radiation Therapy (SBRT) in Stage 0-II Breast Cancer: A Report of 208 Cases with up to 39 Month Follow-Up

Abstract

Purpose: Randomized trials in selected early stage breast cancer patients with up to 10 year follow-up have proven that Accelerated Partial Breast Irradiation (APBI) given via High Dose Rate (HDR) implant bid in 5 days is equivalent to whole breast irradiation (WBI) given qd in 5-6 weeks in regard to breast tumor local recurrence (LR) [1-2]. However, complications with APBI implant in a Medicare database review have been significant, with 3.95% of women requiring Mastectomy, 16.2% developing infections, and another 16.3% experiencing non-infection complications including rib fractures, fat necrosis, and breast pain [3]. Recently APBI using non-invasive Intensity Modulated Radiation Therapy (IMRT) or Stereotactic Body Radiation Therapy (SBRT) given qd in 5 fractions has been shown in another randomized trial with 10 year follow-up to be equivalent to qd WBI in 6 weeks, with respect to LR [4]. IMRT/SBRT was superior in regard to acute effects, late effects, and cosmesis. In the randomized clinical trial of APBI IMRT/SBRT, the Clinical Target Volume (CTV) was defined by the injection of individual fiducial markers bordering the surgical cavity. We have used the Biozorb fiducial system to localize the CTV for SBRT. We sought to confirm the APBI SBRT/IMRT results with this simpler less labor intensive fiducial system.