BACKGROUND: JCOG1212 is a dose-finding and efficacy confirmatory study of concurrent superselective intra-arterial infusion of cisplatin and radiotherapy (RADPLAT) for locally advanced primary squamous cell carcinoma of the maxillary sinus (cT4a,bN0M0). In this study, we report the results of the final analysis of the efficacy confirmation phase for the T4a cohort with 5-year follow-up data to evaluate the late adverse events and long-term efficacy. METHODS: Based on the results of the dose-finding phase, the efficacy confirmation phase consisted of seven weekly intra-arterial infusions of cisplatin 100 mg/m RESULTS: Between April 2014 and August 2018, 64 patients were included in the analysis (one ineligible patient was excluded)
31 patients were treated with three-dimensional conformal radiation therapy (3D-CRT) and 33 with intensity modulated radiation therapy (IMRT). The 5-year overall survival, event-free survival, and local event-free survival was 71.9, 54.7, and 57.5%, respectively. In terms of late adverse events, grade 3 or higher non-hematologic toxicity was observed in 42.9% of 63 patients (retinopathy: 12, cataract: 10, osteonecrosis of mandible: 4, etc.). Grade 3 and 4 cataracts of affected side appeared in 22.6% (7/31) of the 3D-CRT group compared to 3.1% (1/32) in the IMRT group. Twenty-one patients had died, with 15 from the primary disease, 5 from other causes, and 1 from treatment-related cause. CONCLUSION: The prognosis of RADPLAT was favorable after 5-year follow-up with acceptable late adverse events and low proportion of treatment related death.