ESTRO 2024 - Abstract Book

S1004

Clinical - Gynaecology

ESTRO 2024

2 Max-Planck-Institut for Metabolism Research, programme VINCI (“Volume Imaging in Neurological Research, Co Registration and ROIs included”), https://vinci.sf.mpg.de

846

Poster Discussion

Adaptive strategies for external beam radiotherapy in cervical cancer: a systematic review.

Amerah Alshamrani 1,2 , Marianne Aznar 1 , Peter Hoskin 3 , Robert Chuter 3,1 , Cynthia Eccles Eccles 3,1

1 The university of Manchester, Faculty of Biology, Medicine and Health, Manchester, United Kingdom. 2 Princess Nourah bint Abdulrahman University, Department of Radiological Sciences, Riyadh, Saudi Arabia. 3 Christie NHS Foundation Trust., Radiation oncology, Manchester, United Kingdom

Purpose/Objective:

Adaptive radiotherapy (ART) can enhance treatment precision for cervical cancer. However, the increased workload and a lack of consensus on the most suitable ART approach have restricted its clinical implementation. This systematic review assessed current cervical cancer ART to define the optimal approach.

Material/Methods:

A systematic review of literature published between January 2012 and May 2023 was conducted to identify ART approaches used, and compare the dosimetric benefits, and resources required for each ART approach for the treatment of patients with cervical cancer. The searches followed PRISMA guidelines (1) and employed PubMed/Medline, Cochrane Library, and Web of Science databases, supplemented with the University of Manchester digital library, Google Scholar, and papers retrieved from reference lists. Excluded from our review were abstracts, conference abstracts, reviews, and articles unrelated to ART management, proton therapy, brachytherapy, or qualitative studies. The search terms: ‘adaptive radiotherapy’, ‘cervical cancer’, ‘MRI guided radiotherapy’, ‘IGART’, ‘plan of the day’, ‘online ART’, ‘offline ART’ and ‘CBCT’ were used. ART approaches were categorised according to ‘On Target 2’ (2) as reactive, proactive/ library of plan (LOP), scheduled, or real-time. The dosimetric analysis included the primary clinical target volume (CTV-T), the cervix and uterus, as well as the nodal target (CTV-N). The organs at risk (OARs) included the bladder, sigmoid, bowel, and rectum.

Results:

16 Articles met the inclusion criteria. These included 12 retrospective simulation planning studies (3–14), and 4 studies with clinically-implemented strategies: three on LOP and one on reactive (15–18).

ART Approaches

Four different approaches were observed for the creation of LOP: i) increasing CTV-PTV margins incrementally based on a single planning scan (n=1), ii) using multiple planning images and a fixed margin (n=2), iii) using multiple planning images and an ITV (n=8) and iv) involving the use of CBCT images and CTV-T contours from pre-