ESTRO 2025 - Abstract Book

S1782

Clinical – Upper GI

ESTRO 2025

However, the optimum method to delineate the tumour for radiotherapy is unclear. We performed a scoping review to systematically search the literature for evidence regarding the use of MRI to define the target volume delineation for radiotherapy planning in gastric adenocarcinoma. Material/Methods: We systematically searched Medline [Ovid], Embase [Ovid], Cochrane Library [Wiley], Scopus [Elsevier] databases in May 2024 using text words and Medical Subject Heading (MeSH). The comprehensive search strategies were designed and translated for each database by a highly experienced librarian (BC). No date or study type restrictions were used. Searches were limited by English language only. Case studies or conference abstracts were considered. Studies unrelated to radiotherapy planning were excluded, as were review articles, editorials, diagnostic test accuracy studies, response assessment, or prognostic studies. Results: Following the systematic search, 1323 records were identified. (Fig.1) One further record was identified during manual citation checking. There were 571 duplicates, leaving 753 records for screening. 34 full-text articles were assessed for eligibility and 13 were included in the scoping review (9 conference abstracts, 3 case reports and 1 case series including 8 patients). Five texts by Tanaka et al described the role of radiotherapy for haemostasis in gastric cancer, including the role of MRI for post-treatment assessment compared to endoscopy. Van Pelt et al developed an MRI protocol using pineapple juice as oral preparation and found that a T2-weighted exhale respiratory navigator triggered sequence was better for target delineation. For treatment planning, a mDixon sequence with a large field-of-view was feasible. Diffusion weighted imaging was best for staging and treatment response monitoring. Driever et al and Milligan et al both assessed gastric wall motion with standard T2-weighted MRI sequences. Mittauer et al and Rosenburg et al investigated the need for daily adaptive planning to reduce margins and subsequent dose to normal tissues.