ESTRO 2023 - Abstract Book

S360

Sunday 14 May 2023

ESTRO 2023

Conclusion The present study demonstrates the impact of gEUD optimization and Rapidplan on all rectum endpoint complications.

Surprisingly, the introduction of IMRT and VMAT had no radiobiological impact on rectum toxicity.

Proffered Papers: Breast, GI and paediatrics

OC-0455 Salvage HDR interventional radiotherapy for Chest wall recurrences after mastectomy and irradiation T. Soror 1 , M. Banys-Paluchowski 2 , C. Melcherta 1 , K. Muras 2 , M. Xie 2 , D. Rades 1 , J. Rody 2 , G. Kovács 3 1 University of Lübeck, Radiatiation Oncology, Lübeck, Germany; 2 University of Lübeck, Obstetrics and Gynecology, Lübeck, Germany; 3 Università Cattolica del Sacro Cuore, Gemelli-INTERACTS, Rome, Italy Purpose or Objective Local and locoregional recurrences following mastectomy and external irradiation in locally advanced breast cancer patients remain a frequent clinical problem. The local recurrence rate (LR) rate after mastectomy and post-operative irradiation may be as low as 1.6% in node-negative disease or 8.1% in node-positive breast cancer. The purpose is to investigate the technical feasibility, safety, and efficacy of interstitial perioperative high-dose-rate interventional radiotherapy (HDR-IRT, brachytherapy as a salvage local treatment combined with surgery for local recurrences of chest wall following mastectomy and previous external beam radiation treatment (EBRT). Materials and Methods A retrospective analysis of patients treated with interstitial HDR-IRT in combination with local surgery of a chest wall recurrence of breast cancer after previous treatment with mastectomy and EBRT from 2008 to 2020. After the surgical resection of the LR, the tumor bed was marked with metallic surgical clips. Interstitial plastic catheters were implanted and sutured to the tumor bed in a single plane with a 2 cm margin. The catheters were kept parallel to each other with an in-between distance of 8 – 12 mm. Clinical target volume (CTV) included the estimated tumor bed, the surgical clips, and a safety margin of 10 – 20 mm excluding the skin.