ESTRO 2024 - Abstract Book

S193

Brachytherapy - GI, paediatric, miscellaneous

ESTRO 2024

3. Bromham N, Kallioinen M, Hoskin P, Davies RJ; Guideline Committee. Colorectal cancer: summary of NICE guidance. BMJ. 2020;368:m461. Published 2020 Mar 2. doi:10.1136/bmj.m461

4. Snell KI, Hua H, Debray TP, et al. Multivariate meta-analysis of individual participant data helped externally validate the performance and implementation of a prediction model. J Clin Epidemiol. 2016;69:40-50. doi:10.1016/j.jclinepi.2015.05.009 5. Karageorgou M, Hughes DM, Myint AS, Pritchard DM, Bonnett LJ. Clinical prediction models assessing response to radiotherapy for rectal cancer: protocol for a systematic review. Diagn Progn Res. 2022;6(1):19. Published 2022 Oct 6. doi:10.1186/s41512-022-00132-y

6. Page MJ, McKenzie JE, Bossuyt PM, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ. 2021;372:n71. Published 2021 Mar 29. doi:10.1136/bmj.n71

7. Fernandez-Felix BM, López-Alcalde J, Roqué M, Muriel A, Zamora J. CHARMS and PROBAST at your fingertips: a template for data extraction and risk of bias assessment in systematic reviews of predictive models. BMC Med Res Methodol. 2023;23(1):44. Published 2023 Feb 17. doi:10.1186/s12874-023-01849-0. 8. Moons KG, Altman DG, Reitsma JB, et al. Transparent Reporting of a multivariable prediction model for Individual Prognosis or Diagnosis (TRIPOD): explanation and elaboration. Ann Intern Med. 2015;162(1):W1-W73. doi:10.7326/M14-0698

2657

Proffered Paper

Dose Escalated Radiotherapy and Organ Preservation in Rectal Cancers : A prospective Phase II study

Reena Engineer 1 , Avanish Saklani 2 , Debanjali Dutta 1 , Rahul Krishnatry 1 , Shiv Kumar Gudi 1 , Mufaddal Kazi 2 , Suman Ankathi 3 , Prachi Patil 4 , Ashwin Desouza 2 1 Tata Memorial Centre, Radiation Oncology, Mumbai, India. 2 Tata Memorial Centre, Surgical Oncology, Mumbai, India. 3 Tata Memorial Centre, Radiodiagnosis, Mumbai, India. 4 Tata Memorial Centre, Gasteroinntestinal, Mumbai, India

Purpose/Objective:

Patients achieving complete / near complete clinical response (cCR/nCR) are managed with watch and wait approach leading to organ preservation. With routing doses of Radiotherapy of 45-50 Gy/25# only 20-25% achieve cCR/nCR. Increasing the dose of radiotherapy to primary rectal tumor is associated with increase in complete response and is recommended for patients enrolled for NOM of rectal cancers(1). Further the boost radiotherapy can reduce the local regrowth rate from 20-30% to less than 15 % thereby aiding the non-operative management of these cancers (2).

The dose escalation can be done by using Ir192 HDR brachytherapy applied by intracavitary radiation or with external beam radiotherapy.