S721
Clinical – Lower GI
ESTRO 2026
Proffered Paper 3240
measures. Material/Methods:
Early regression index-guided dose escalation in locally advanced rectal cancer: long term results of the prospective THUNDER-2 trial (NCT04815694) Giuditta Chiloiro 1 , Angela Romano 1 , Flavia de Giacomo 1 , Luca Boldrini 1 , Francesco Bono 1 , Matteo Nardini 1 , Lorenzo Placidi 1 , Davide Cusumano 2 , Huong Elena Tran 1 , Giulia Panza 1 , Carlo Guglielmo Cattaneo 3 , Filippo Quattrocchi 3 , Natalia Barogi 1 , Ilaria Nacci 4 , Roberta Menghi 5 , Lorenzo Ferri 5 , Federico Barbaro 6 , Silvia Pecere 6 , Maria Antonietta Gambacorta 1 1 Radiation Oncology Department, Fondazione Policlinico Universitario "A.Gemelli" IRCCS, Rome, Italy. 2 Radiation Oncology Department, Mater Olbia Hospital, Olbia, Italy. 3 Radiation Oncology Department, Catholic University of the Sacred Heart, Rome, Italy. 4 Advanced Radiology Center, Fondazione Policlinico Universitario "A.Gemelli" IRCCS, Rome, Italy. 5 Medical and Surgical Sciences Department, Fondazione Policlinico Universitario "A.Gemelli" IRCCS, Rome, Italy. 6 Surgical Digestive Endoscopy, Fondazione Policlinico Universitario "A.Gemelli" IRCCS, Rome, Italy Purpose/Objective: Pathologic complete response (pCR) after neoadjuvant chemoradiotherapy (nCRT) in locally advanced rectal cancer (LARC) is associated with improved survival and supports organ-preserving strategies. However, response to nCRT is heterogeneous. The Early Regression Index (ERI), based on tumor volume change during treatment, has emerged as a potential predictive biomarker. The THUNDER-2 phase II trial evaluated whether MRI-guided adaptive dose escalation could improve complete response (CR) rates in patients identified as poor responders by ERI. Material/Methods: Patients with LARC (cT3-cT4 low rectal cancer or cN+) underwent MRI-guided nCRT with concurrent capecitabine or 5-Flurouracil. ERI was calculated between simulation and the 10th fraction. Patients with ERI ≤ 13.1 were classified as responders and continued standard RT dose (55 Gy on tumor and corresponding mesorectum); those with ERI >13.1 (non-responders) received an adaptive boost to 60.1 Gy on the residual gross tumor volume using online MRI-guided adaptive radiotherapy (oART). Clinical and pathological response was assessed at restaging; CR was defined as clinical complete response (cCR) or pathological complete response (pCR). Patients with cCR were considered for non-operative management (NOM), including Watch & Wait or local excision (LE). Results: Sixty-two patients were evaluable (Figure 1). Thirty (48.4%) were responders and 32 (51.6%) non- responders. Complete response at two years was observed in 18/30 responders (60.0%) and 7/32 non-
A prospective analysis was done on data from 40 patients who completed European Organization for Research and Treatment of Cancer (EORTC) (3)validated generalized cancer-specific QLQ- C30 and colorectal cancer specific QLQ-CR29 questionnaires (Hindi & English language versions) before, at the end, 1 month and 3 months after therapy. All statistical analyses were done with Jamovi 2.3.28 software. A p level of <0.05 was accepted as statistically significant. Results: We observed that Global health status and symptoms’ scores showed significant improvement from baseline to by the end of 3 months after RT, indicating enhanced overall health perception by the patients & treatment efficacy in alleviating symptoms.Physical (p value-0.046), role, cognitive, emotional and social function mean scores had progressive improvement from baseline through end of RT and at 1-3 months post RT. Financial burden was observed throughout the treatment process. Fatigue improved significantly as time progressed after RT. Anxiety, weight loss, body image has shown improving trend over time. Sexual interest in males & females was improved 3 months post RT. Conclusion: Changes observed in quality of life from baseline through end of RT and after 1-3 months indicate that starting and completing the treatment has provided patient emotional security, improved patient’s perception of their over-all health as the symptoms were relieved & were able to continue their daily life activities. Consistent economic strain underscores the need for dedicated cancer health policies that support patients throughout treatment & recovery. References: Arraras Urdaniz JI, Arias de la Vega F, Vera García R, Burgaleta AM, Aguillo MM, Iturre EV, et al. Quality of life assessment through the EORTC questionnaires of locally advanced rectal cancer patients treated with preoperative chemo-radiotherapy. Clin Transl Oncol. 2006 Jun 1;8(6):423–9. 2.Guren MG, Dueland S, Skovlund E, Fosså SD, Poulsen JP, Tveit KM. Quality of life during radiotherapy for rectal cancer. Eur J Cancer Oxf Engl 1990. 2003 Mar;39(5):587–94. 3.csi. EORTC – Quality of Life. 2017 [cited 2024 Jul 17]. EORTC Quality of Life website | EORTC Quality of Life Group website. Available from: https://qol.eortc.org/ Keywords: Rectal cancer, Quality of Life, NACTRT
Made with FlippingBook - Share PDF online