The Feasibility of Quality Assurance in the TOPGEAR International Phase 3 Clinical Trial of Neoadjuvant Chemoradiation Therapy for Gastric Cancer (an Intergroup Trial of the AGITG/TROG/NHMRC CTC/EORTC/CCTG).

PURPOSE

The TOPGEAR phase 3 trial hypothesized that adding preoperative chemoradiation therapy (CRT) to perioperative chemotherapy will improve survival in patients with gastric cancer. Owing to the complexity of gastric irradiation, a comprehensive radiation therapy quality assurance (RTQA) program was implemented. Our objective is to describe the RTQA methods and outcomes.

METHODS AND MATERIALS

RTQA was undertaken in real time before treatment for the first 5 patients randomized to CRT from each center. Once acceptable quality was achieved, RTQA was completed for one-third of subsequent cases. RTQA consisted of evaluating (1) clinical target volume and organ-at-risk contouring and (2) radiation therapy planning parameters. Protocol violations between high- (20+ patients enrolled) and low-volume centers were compared using the Fisher exact test.

RESULTS

TOPGEAR enrolled 574 patients, of whom 286 were randomized to receive preoperative CRT and 203 (71%) were included for RTQA. Of these, 67 (33%) and 136 (67%) patients were from high- and low-volume centers, respectively. The initial RTQA pass rate was 72%. In total, 28% of cases required resubmission. In total, 200 of 203 cases (99%) passed RTQA before treatment. Cases from low-volume centers required resubmission more often (44/136 [33%] vs 13/67 [18%]; P = .078). There was no change in the proportion of cases requiring resubmission over time. Most cases requiring resubmission had multiple protocol violations. At least 1 aspect of the clinical target volume had to be adjusted in all cases. Inadequate coverage of the duodenum was most common (53% major violation, 25% minor violation). For the remaining cases, the resubmission process was triggered secondary to poor contour/plan quality.

CONCLUSIONS

In a large multicenter trial, RTQA is feasible and effective in achieving high-quality treatment plans. Ongoing education should be performed to ensure consistent quality during the entire study period.