Quality assurance of radiotherapy in the Japan Clinical Oncology Group trial 0211 concerning concurrent chemoradiotherapy for localized nasal NK/T-cell lymphoma: The individual case review

Abstract

17561 Background: It is challenging to conduct a high quality multi-institutional clinical trial for localized nasal NK/T-cell lymphoma due to the anatomical complexity and its rarity. The purpose of this study was to evaluate the compliance with protocol guidelines in concurrent chemoradiotherapy for this disease among radiotherapy institutions participating in a multi-center phase I/II JCOG trial 0211. Methods: The treatment consisted of radiotherapy 50 Gy and 3 cycles of DeVIC chemotherapy [carboplatin, etoposide, ifosfamide, dexamethasone] (Yamaguchi M, et al.: Proc ASH, 2005). CT-based three-dimensional treatment planning was required to cover adequately target volumes and to minimize doses to organs at risk such as the eyes, the brain stem and the spinal cord. Patient data were sent to the review center after the treatments have been finalized. The following parameters were evaluated by the quality assurance review board: treatment records and charts; simulation films; portal images; prescribed dose; dose fractionation and overall treatment time; dose distributions; and dose to risk organs. Results: At the time of phase I analysis, 10 patients were enrolled in this study. In 2 of 10 cases, process of treatment planning was not available. There was no protocol violation. Major deviations were identified as follows: Delineation of clinical target volume (< 2 cm from the edge of the gross tumor volume at any direction), 2/10; dose distribution (not covered by 90%-115% isodose line), 1/10; and dose to optic chiasm (>40 Gy), 1/10. All cases were compliant in prescribed dose, dose fractionation, and overall treatment time. In the last 4 of 10 cases, attending radiation oncologists at the participating institutions were contacted by the radiation oncology study chair and they discussed the treatment planning just after patient enrollment. These 4 cases were all protocol compliant compared to 6 cases with 4 major deviations. Conclusions: Individual case review is essential in a multi-center clinical trial to keep enrolled cases protocol compliant and minimize inter-institutional variations. We expect that our quality assurance program will maintain the quality of the JCOG trial 0211. No significant financial relationships to disclose.