Superselective intra-arterial chemoradiotherapy for maxillary sinus squamous-cell carcinoma: results from the T4bN0M0 cohort of JCOG1212

BACKGROUND: JCOG1212 is a multi-institutional prospective single-arm trial evaluating the efficacy and safety of superselective intra-arterial cisplatin infusion with concomitant radiotherapy (RADPLAT) for locally advanced maxillary sinus squamous-cell carcinoma (MS-SCC). We previously reported the results for the T4aN0M0 cohort (n = 64), in which RADPLAT was shown to be feasible and to provide favorable survival outcomes. This report presents the results for the T4bN0M0 cohort. PATIENTS AND METHODS: ) for seven cycles in combination with radiotherapy (70 Gy in 35 fractions). The primary endpoint was 3-year overall survival (OS), with a predefined efficacy threshold of 35% and a one-sided alpha of 5%. Secondary endpoints included event-free survival (EFS), local EFS (LEFS), clinical response, and toxicity. RESULTS: Sixty-four patients were enrolled from 20 institutions. The 3-year OS was 68.8% [90% confidence interval (CI) 58.1% to 77.2%], exceeding the efficacy threshold. The clinical complete response rate was 54.7%. The 3-year EFS and LEFS was 51.6% (95% CI 38.8% to 63.0%) and 57.8% (95% CI 44.8% to 68.8%), respectively. With regard to acute adverse events, neutropenia ≥ grade 3 (18.0%), mucositis ≥ grade 3 (23.0%), hearing impairment ≥ grade 2 (3.3%), and stroke ≥ grade 2 (1.6%) were observed. No grade 2 ≥ creatinine increase was observed. There were no treatment-related deaths. CONCLUSIONS: RADPLAT achieved favorable survival outcomes with acceptable toxicity in patients with T4bN0M0 MS-SCC. These results establish RADPLAT as a feasible and effective organ-preserving treatment and demonstrate the potential of intra-arterial chemoradiotherapy for unresectable MS-SCC.