On the feasibility of improved target coverage without compromising organs at risk using online adaptive stereotactic partial breast irradiation (A‐SPBI)

Abstract

Purpose Describe an early‐adopting institution's experience with online adaptive radiation for stereotactic partial breast irradiation. Methods and materials Retrospective review of 22 women treated between May 2021 and March 2022 with adaptive stereotactic partial breast irradiation. A total of 106 of 110 fractions were evaluated for dosimetric changes in target coverage and organ‐at‐risk (OAR) dose. Patient set up with stereotactic wooden frame and adapted per fraction. Treatment and planning times were collected prospectively by radiation therapists. Results Scheduled PTV 30 Gy was <95% in 72.1% and <90% in 38.5% of fractions, and both PTV and CTV coverage were improved significantly after adaption, and 83.7% of fractions were delivered as adapted per physician choice. There was no difference in OAR coverage. Average adaptive treatment planning took 15 min and average time‐on‐couch was 34.4 min. Conclusions Adaptive stereotactic breast irradiation resulted in improved target coverage with equivalent dosing to OARs in an efficient and tolerated treatment time. Improved target coverage allowed for decreased PTV margins compared to prior trial protocols that may improve acute and late toxicities.

Improved Dosimetry and Plan Quality for Accelerated Partial Breast Irradiation Using Online Adaptive Radiation Therapy: A Single Institutional Study

“…In this work, we present our institution's initial experience treating early-stage breast cancer patients with 5-fraction APBI on the kV-cone beam CT (CBCT) guided Varian Ethos platform. Although APBI treatment with Ethos has been previously described, 19 only select dose volume histogram (DVH) differences between scheduled (reference plans calculated on daily CBCT anatomy) and adapted plans were compared. Adding to the literature, our study includes a detailed summary of plan selection, daily target contouring, and planning and treatment timing.…”

Physicists should perform reference planning for CBCT guided online adaptive radiotherapy

“…Recent advancements in online imaging, AI‐generated contouring, and auto‐planning in RT have enabled the creation and successful clinical adoption of an efficient CBCT based oART platform 1–4 . This oART process requires the creation of a reference plan generated on the traditional simulation CT and baseline anatomical contours.…”

Simulation and pre-planning omitted radiotherapy (SPORT): a feasibility study for prostate cancer

“…The attending physician then reviews the quality of both plans before deciding which to use for treatment. Numerus studies have demonstrated the feasibility of utilization of the Ethos system for ART for different cancer sites with real patient cases or emulation studies following the standard adaptive workflow [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. The goal of this study is to test our novel workflow, in which the required individually optimized preplan is replaced by a properly selected plan from a pre-built plan library.…”