View in EDS

Dose Escalation Using Magnetic Resonance Guided High-Dose-Rate Endorectal Brachytherapy to Enhance Clinical Response after Neoadjuvant Radiotherapy in Rectal Adenocarcinoma.

Saved in:
Bibliographic Details
Title: Dose Escalation Using Magnetic Resonance Guided High-Dose-Rate Endorectal Brachytherapy to Enhance Clinical Response after Neoadjuvant Radiotherapy in Rectal Adenocarcinoma.
Authors: Engineer, R.1 (AUTHOR), Datta, D.1 (AUTHOR), Gudi, S.2 (AUTHOR), Krishnatry, R.1 (AUTHOR), deSouza, A.3 (AUTHOR), Ankathi, S.K.3 (AUTHOR), Kohle, S.4 (AUTHOR), Saklani, A.3 (AUTHOR)
Source: International Journal of Radiation Oncology, Biology, Physics. 2023 Supplement, Vol. 117 Issue 2, pe295-e295. 1p.
Subjects: Rectal cancer, High dose rate brachytherapy, Magnetic resonance, Radioisotope brachytherapy, Surgical stomas, Preservation of organs, tissues, etc., Adenocarcinoma
Abstract: To assess the proportion of patients with rectal adenocarcinoma achieving clinical complete response after neoadjuvant chemoradiation (NACTRT) and MR guided endorectal brachytherapy boost (MR-ERBT) Patients with rectal cancers (T2-T4/N0-N+) treated with concurrent chemoradiotherapy (50Gy/25# with Capecitabine) between June-2017 to April-2022. Post RT, patients having residual non-circumferential lesions <8cm in length were administered escalated-dose MR-ERBT with Ir192 HDR source. A median dose of 12Gy (8-15Gy) in 3 (2-3) fractions at 3-5 day intervals was delivered using MR-ERBT after external radiation. Data on near complete/complete clinical response (nCR/cCR) rates, local regrowth rates and clinical outcome were collected for analysis. Of the 145 patients who received MR-ERBT, majority were staged as T3(78.7%) and N1-2 (77.5%) rectal cancers. Median tumor length was 4cm and 123 (85%) of the tumors were located in the lower rectum (0-5cm from anal verge). Seventy-six (52%) patients achieved cCR or nCR (37 cCR, 39 nCR) and were advised observation or watch and wait (WW) management. The 69 patients having partial response were advised surgery. The patients having nCR 16 (29%) underwent resection, of these 10 (62%) had pathological complete response (pCR). The patients with partial or poor response, 57 underwent resection and of these 11 (19%) had pCR, 12 patients refused surgery due to fear of permanent stoma and continued to be on follow up. Of the 79 patients undergoing resection, 36 (45.5%) had sphincter preserving surgeries. At the median follow up of 30 months, local regrowth was seen in 8 (10.5%) of patients on WW and 6 were surgically salvaged while other 2 had synchronous metastatic relapse. Thus, 56 (41%) achieved organ preservation and continued to be on WW management. Twelve (8,2%) patients developed distant metastasis in the entire cohort, 3 in the WW group and 9 in the resected group. There were no pelvic recurrences seen in the resected patients. The disease-free survival at 3 years were (96.1% vs 89% Observation vs. resected (p_0.05) respectively. The overall survival at 3 years were (93% vs 98% Observation vs. resected (p_0.44) respectively. Late rectal toxicity was observed in 16(11%) patients on observation Dose Escalated MR-EBRT is an effective and safe method to enhance complete clinical response, thus improving the rate of organ preservation for distal rectal cancers. [ABSTRACT FROM AUTHOR]
Copyright of International Journal of Radiation Oncology, Biology, Physics is the property of Pergamon Press - An Imprint of Elsevier Science and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
Description
Abstract:To assess the proportion of patients with rectal adenocarcinoma achieving clinical complete response after neoadjuvant chemoradiation (NACTRT) and MR guided endorectal brachytherapy boost (MR-ERBT) Patients with rectal cancers (T2-T4/N0-N+) treated with concurrent chemoradiotherapy (50Gy/25# with Capecitabine) between June-2017 to April-2022. Post RT, patients having residual non-circumferential lesions <8cm in length were administered escalated-dose MR-ERBT with Ir192 HDR source. A median dose of 12Gy (8-15Gy) in 3 (2-3) fractions at 3-5 day intervals was delivered using MR-ERBT after external radiation. Data on near complete/complete clinical response (nCR/cCR) rates, local regrowth rates and clinical outcome were collected for analysis. Of the 145 patients who received MR-ERBT, majority were staged as T3(78.7%) and N1-2 (77.5%) rectal cancers. Median tumor length was 4cm and 123 (85%) of the tumors were located in the lower rectum (0-5cm from anal verge). Seventy-six (52%) patients achieved cCR or nCR (37 cCR, 39 nCR) and were advised observation or watch and wait (WW) management. The 69 patients having partial response were advised surgery. The patients having nCR 16 (29%) underwent resection, of these 10 (62%) had pathological complete response (pCR). The patients with partial or poor response, 57 underwent resection and of these 11 (19%) had pCR, 12 patients refused surgery due to fear of permanent stoma and continued to be on follow up. Of the 79 patients undergoing resection, 36 (45.5%) had sphincter preserving surgeries. At the median follow up of 30 months, local regrowth was seen in 8 (10.5%) of patients on WW and 6 were surgically salvaged while other 2 had synchronous metastatic relapse. Thus, 56 (41%) achieved organ preservation and continued to be on WW management. Twelve (8,2%) patients developed distant metastasis in the entire cohort, 3 in the WW group and 9 in the resected group. There were no pelvic recurrences seen in the resected patients. The disease-free survival at 3 years were (96.1% vs 89% Observation vs. resected (p_0.05) respectively. The overall survival at 3 years were (93% vs 98% Observation vs. resected (p_0.44) respectively. Late rectal toxicity was observed in 16(11%) patients on observation Dose Escalated MR-EBRT is an effective and safe method to enhance complete clinical response, thus improving the rate of organ preservation for distal rectal cancers. [ABSTRACT FROM AUTHOR]
ISSN:03603016
DOI:10.1016/j.ijrobp.2023.06.2304