First Application of Demand-Triggered Online Adaptive Radiotherapy in the Treatment of Cervical Cancer: A Clinical Report.

Gynecology cancers can reap significant benefits from adaptive radiation therapy (ART) for four major reasons: organ motion, organ deformation, density change, and cavity filling. There are three recognized types of adaptive radiotherapy: offline, online, and real-time. This balance of improved dosimetry versus clinic resources, as well as the optimal timing for adaptations, is still under investigation. The emergence of on-demand online adaptive radiotherapy (OART) can solve the above problems. In this context, we introduce two patients with cervical cancer who used on-demand OART for the first time. One patient with cervical cancer received radical radiotherapy on the United Imaging uCT-ART platform, and another patient with cervical cancer received postoperative adjuvant radiotherapy. The radiotherapy process used OART, which was triggered by senior radiotherapists, assisted by artificial intelligence, and guided by fan-beam computer tomography. Patient 1, who was 54 years old with cervical squamous cell carcinoma, International Federation of Gynecology and Obstetrics (FIGO) stage ⅢC1, underwent radical concurrent chemoradiotherapy. The target volume was reduced in the late stage of radiotherapy. The target volume coverage of the OART plan was better, and the bladder and rectum doses were lower than those of the image-guided radiotherapy plan. Patient 2, who was 56 years old with cervical adenocarcinoma, FIGO stage ⅡA1, underwent postoperative concurrent chemoradiotherapy. If the fractionated treatment during radiotherapy was carried out according to the original plan, treatment off-target would occur, while the OART plan could ensure target coverage. The acute toxic reactions that occurred in both patients during radiotherapy were patient-reported outcome Common Terminology Criteria for Adverse Events 1-2, and no toxic reactions of grade 3 or above occurred. This is the first description of the successful implementation of the uCT-ART-based OART system in EBRT for cervical cancer.