Jelena Lukovic, MD, FRCPC, MPH, Radiation Onologist, University of Toronto, Princess Margaret Cancer Centre speaks about the ASTRO 2021 Abstract – 73 The Feasibility of Quality Assurance in the TOPGEAR International Phase III Clinical Trial of Neoadjuvant Chemoradiotherapy for Gastric Cancer (An Intergroup Trial of the AGITG/TROG/EORTC/CCTG).
Link to Abstract:
https://plan.core-apps.com/myastroapp2021/abstract/ab077756-3746-4723-8871-8f9b1cfa329b
Abstract:
Intention):
The TOPGEAR (Trial of Preoperative Therapy for Gastric and Esophagogastric Junction Adenocarcinoma) worldwide phase III trial hypothesized that supplementing perioperative chemotherapy with preoperative chemoradiation (CRT) would enhance survival in patients with gastric cancer. A sophisticated radiation therapy quality assurance (RTQA) methodology was created due to the intricacy of stomach irradiation. The purpose of this paper is to describe the RTQA procedures and results.
Components:
For the first 5 pts randomized to CRT from each center, RTQA was conducted in ‘real time’ prior to therapy. After achieving acceptable quality, RTQA was finished for one-third of the remaining cases. The following parameters were evaluated as part of the RTQA: 2) RT planning parameters (CT simulation, dose prescription/planning technique, per-protocol planning limits); 1) clinical target volume (CTV) and organ-at-risk (OAR) contouring The Fisher’s exact test was used to assess protocol violations across high-volume (defined as 20+ points enrolled) and low-volume locations.
Outcomes:
554 points from 70 centers had been enrolled as of December 2020. In all, 277 patients were randomized to receive RT, and 196 (71%) were included in the RTQA study; of these, 57 (29%) and 139 (71%) came from high- and low-volume centers, respectively. The original RTQA pass rate (n=141) was 72 percent. The initial pass rate did not differ significantly between high- and low-volume facilities (79 percent vs 69 percent; p = 0.22).
The 55 cases that needed to be resubmitted were given comprehensive criticism, and the majority of them had several procedural violations. In 49/55 (89%) cases, at least one component of the CTV had to be altered due to insufficient coverage of the duodenum down to the third most usually observed portion (n=28/55, 51%). The infractions of the CTV contouring protocol are listed in Table 1. OARs were generally shaped well, with only five (9%) examples requiring correction. Due to treatment planning violations (kidney dosage, lung dose) in the absence of contouring (CTV, OAR) concerns, two instances failed RTQA.
After resubmission, 192 (98%) of the students passed the RTQA, while four (2%) required a second resubmission.
Implication:
RTQA was found to be practical and useful in creating high-quality RT treatment plans in a large multicenter experiment. To guarantee constant quality of treatment programs throughout the research period, ongoing education and audits should be conducted.