Radiotherapy Quality Assurance Review in the Multi-center Randomized Trial for Limited-disease Small Cell Lung Cancer: The Japan Clinical Oncology Group (JCOG) Trial 0202

Abstract

JCOG introduced radiotherapy (XRT) quality assurance (QA) review in 2002 to improve the quality of clinical trials. This trial was the first one that required on-going XRT QA review in JCOG. The purpose of this study was to analyze the XRT QA score in JCOG 0202. JCOG 0202 was a multi-center phase III trial comparing two types of consolidation chemotherapy after concurrent chemoradiotherapy for limited-disease small cell lung cancer. XRT requirements included a total dose of 45 Gy in 30 fx (BID) without heterogeneity correction; elective nodal irradiation (ENI) of 30 Gy; and at least 1 cm margin around the gross tumor volume (GTV). Dose constraints were defined in regards to the dose to the spinal cord and the lung. Other requirements were overall treatment time and interfraction interval. XRT parameters were screened for compliance during patient accrual and given final compliance score after the completion of accrual. The QA score was given as per protocol (PP), deviation acceptable (DA), violation unacceptable (VU), and incomplete/not evaluable (I/NE) by both an independent radiation oncologist (N.S.) and the radiation oncology principal investigator (S.I.). A total of 283 cases were accrued. Of these, 204 were fully evaluable excluding 79 I/NE cases (ineligible, 5; XRT incomplete, 12; incomplete data submission, 62). Partially evaluable cases were included for evaluation in each item. There were 18 VU in GTV coverage (8% of 238 evaluated); 4 VU and 23 DA in ENI (2% and 9% of 243 evaluated, respectively). No VU was found in overall treatment time, interfraction interval and dose calculation, while some VU were observed in organs at risk (1 VU in the lung and 5 VU in the spinal cord). In total, overall XRT compliance (PP + DA) was 92% (187 of 204 fully evaluable). Comparison between the former and the latter half of the accrued cases revealed that the number of VU and DA had been decreased: VU/GTV, 13 to 5; VU/ENI, 3 to 1; DA/ENI, 20 to 3. The XRT QA score of JCOG 0202 seemed to be acceptable for providing scientifically reliable results. QA program will continue to be an integral part of multi-center clinical trials involving XRT. Introduction of dry-run procedure and intensive feedback to participating institutions will be considered for further improvement in JCOG trials.