ESTRO 2022 - Abstract Book

S492

Abstract book

ESTRO 2022

S. Lozares 1 , V. Gonzalez 2 , S. Pellejero 3 , J.A. Font 1 , A. Gandía 1 , D. Villa 1 , V. Alba 1 , S. Jiménez 1 , J. Díez 1 , R. Castro 1 , A. González 1 1 H.U. Miguel Servet, Física y P.R., Zaragoza, Spain; 2 Fundacion Instituto Valenciano de Oncologia, Física y P.R., Valencia, Spain; 3 Complejo Hospitalario de Navarra, Radiofísica y P.R., Pamplona, Spain

Purpose or Objective This study presents the dosimetric calculation results with the Axxent electronic brachytherapy (eBT) system for 56 cervical cancer patients. Materials and Methods All cases were first calculated and treated with Ir-192 in 3 different hospital centres, then, retrospectively planned with Axxent and the BrachyCare treatment planning system (with TG- 43 algorithm) specific for Axxent eBT (Técnicas Radiofísicas, Zaragoza-Spain) using CT-study of each patient. The patients presented different stages (Table 1) and were contoured following the ESTRO-ABS- EMBRACE guidelines. Treatment consisted of 50 Gy in 2 weeks of external beam radiotherapy (EBRT), plus 4 sessions of 7 Gy of intracavitary brachytherapy. The planning dosimetric targets are those corresponding to the EMBRACE study, the average D90 and D98of high-risk clinical target volume (HR-CTV) parameters are presented, together with D2cc, D1cc and D0.1cc of organs at risk (OAR) whose are bladder, rectum, and sigma in terms of equivalent dose in 2-Gy fractions (EQD2), including the EBRT.

Results Of all patients calculated, 41 (73%) complied EMBRACE requirements and 15 (27%) did not complied some of the parameters, either HR-CTV coverage or dose in OARs. The average EQD2 of patients meeting the targets and ensuring a high probability of local control (D90 >90 Gy) are shown in Table 2.

Conclusion