The SINTART 1 study : a phase II non-randomised controlled trial of induction chemotherapy, surgery, photon-, proton- and carbon ion-based radiotherapy integration in patients with locally advanced resectable sinonasal tumours

Purpose: Sinonasal tumours are rare diseases with poor prognosis. Multimodal approach including surgery is widely used, although no standard therapy has been established in prospective trials. This study assessed activity and safety of an innovative integration of multimodality treatment-induction chemotherapy (ICT), surgery and radiotherapy (RT)-modulated by histology and response to ICT. Methods: Patients with untreated, operable sinonasal tumours with selected histotypes (squamous cell carcinoma, intestinal-type adenocarcinoma, sinonasal undifferentiated and neuroendocrine carcinoma, olfactory neuroblastoma) were enrolled in a single-arm, phase II, multicenter clinical trial. Patients were treated with up to 5 ICT cycles, whose regimen was selected according to histotype, followed either by curative chemo-RT for pts with >= 80% reduction of initial tumour diameter or surgery and adjuvant (chemo)RT. Photon and/or proton/carbon ion-based RT was employed according to the disease site and stage. Primary end-point was 5-year progression-free survival (PFS), secondary end-points were overall survival (OS), ICT objective response rate (ORR) per RECIST 1.1 and safety. Results: Thirty-five patients were evaluable for primary end-point. Fourteen patients (40%) were treated with definitive (CT)RT and 20 (57%) underwent surgery. Five-year PFS was 38% (95% confidence interval [CI], 21-69), with a median PFS of 26 months. Five-year OS was 46% (95% CI, 28-75), with a median OS of 36 months. Three-year PFS-OS for pts achieving PR/CR versus stable disease (SD)/PD to ICT were 49.8-57% versus 43.2-53%, respectively. Three-year PFS for patients achieving major volumetric partial response (>= 80% reduction of initial tumour volume, major partial volumetric response [mPRv]) versus non-mPRv were 82% versus 28% and 3-year OS were 92% versus 36% (p value 0.010 and 0.029, respectively). The ORR to ICT was 54% and 60% across all histotypes and in the sinonasal undifferentiated carcinoma (SNUC) subpopulation, respectively, with 6/15 SNUCs (40%) achieving mPRv. Conclusion: Treatment of advanced sinonasal cancer with histology-driven ICT followed by (CT)RT in responsive patients was feasible. Overall, these findings suggest a possible role of ICT as the primary approach in newly diagnosed, resectable sinonasal tumours-especially SNUC-to select patients with favourable prognosis. Histology heterogeneity limits generalisation of trial results.