ESTRO meets Asia 2024 - Abstract Book

S207

Interdisciplinary – Lower GI

ESTRO meets Asia 2024

after end of TNT with pathology result ypT1N0M0.One patient out 5, consulted after 18 months of loss from sight and had metastatic disease. The 4 remaining patients are lost from follow up to date.

Conclusion:

The high rate of drop-off from follow up after rectum preservation protocol according to the new standards of care after TNT may hinder its implementation within our daily practice. Actions to enhance patient and family education need to be taken in order to ensure good adherence to follow-up guidelines in order to detect relapse timely and treat patients accordingly.

Keywords: rectum cancer, organ preservation, follow-up

References:

1.Doer RR, Dijkstra EA, van Etten B, Marijnen CAM, et RAPIDO collaborative investigators. Short-course radiotherapy followed by chemotherapy before total mesorectal excision (TME) versus preoperative chemoradiotherapy, TME, and optional adjuvant chemotherapy in locally advanced rectal cancer (RAPIDO): a randomised, open-label, phase 3 trial. Lancet Oncol. 2021 Jan;22(1):29-42. doi: 10.1016/S1470-2045(20)30555-6. 2.Conroy T, Bosset JF, Etienne PL, Rio E, et Unicancer Gastrointestinal Group and Partenariat de Recherche en Oncologie Digestive (PRODIGE) Group. Neoadjuvant chemotherapy with FOLFIRINOX and preoperative chemoradiotherapy for patients with locally advanced rectal cancer (UNICANCER-PRODIGE 23): a multicentre, randomised, open-label, phase 3 trial. Lancet Oncol. 2021 May;22(5):702-715. doi: 10.1016/S1470-2045(21)00079 6.

267

Proffered Paper

Impact of locoregional thermoradiation in locally advanced rectal cancer: Prospective phase II trial

Barbara Salas 1 , Laura Ferrera Alayón 1 , C. Paola Tello Valverde 2 , Antonio Alayon 1 , Hans Crezee 2 , Marta LLoret 1

1 Department of Radiation Oncology, University Hospital of Gran Canaria Dr. Negrín, Las Palmas de Gran Canaria, Spain. 2 Department of Radiation Oncology, Amsterdam UMC, Amsterdam, Netherlands

Purpose/Objective:

We aimed to investigate the effect of preoperative radiochemotherapy combined with locoregional hyperthermia (HT) on locally advanced rectal cancer (LARC) patients compared with radiochemotherapy alone.

Material/Methods:

In this double-arm, prospective phase II RTHT-LARC trial (#2020-335-1), after informed consent, 61 patients with LARC were included between 2020-2023. Eligible patients were aged ≥ 18, pathologically confirmed adenocarcinoma and a magnetic resonance imaging (MRI) confirmed LARC stage cT1-2N+M0, cT3N0M0, cT3N+M0, cT4N0M0, and cT4N+M0 (Table 1). Patients were assigned to either the radiochemotherapy group (n=27) or radiochemotherapy + HT group (n=34). All patients were treated with short course radiotherapy, 25Gy in five fractions, once a day for a week. Neo-adjuvant chemotherapy consisted of FOLFOX, CapOx or XELOX. Adjuvant HT was delivered twice a week, with an interval of 72 hours. Primary endpoint was defined as a clinically relevant increase of ≥ 10% in pathological complete response (CR) rate compared to radiochemotherapy group. Secondary