Radiotherapy Results in Locally Advanced Sinonasal Cancer: Turkish Society for Radiation Oncology, Head and Neck Study Group 01-005.

Objectives: This study aims to examine the treatment outcomes and related factors in locally advanced sinonasal cancer across Turkiye.

Methods: Twelve centers participants of the Turkish Society for Radiation Oncology Head and Neck Study Group attended the study. One hundred and ninety-four patients treated with intensity-modulated radiation therapy between 2001 and 2021 were analyzed retrospectively. The survival analysis was performed using the Kaplan-Meier method. Acute and late toxicity were recorded per Common Toxicity Criteria for Adverse Events V4.0.

Results: The median age was 58 years and 70% were male. The majority of tumors were located in maxillary sinus (59%). Most of the patients (%83) had T3 and T4A disease. Fifty-three percent of patients were in stage 4A. Radiotherapy was administered to 80% of the patients in the adjuvant settings. Median 66 Gy dose was administered in median 31 fractions. Chemotherapy was administered concomitantly with radiotherapy in 45% of the patients mostly with weekly cisplatin. No grade ≥4 acute and late toxicity was observed. The median follow-up was 43 months. The 5-year and 10-year overall survival (OS); locoregional recurrence-free survival (LRFS); distant metastasis-free survival (DMFS), and progression-free survival (PFS) rates were 61% and 47%; 69% and 61%; 72%, and 69%, and 56% and 49%, respectively. In the multivariate analysis, several factors demonstrated significant influence on OS, such as performance status, surgery, and lymph node involvement. Moreover, surgery was the key prognostic factor for LRFS. For DMFS, lymph node involvement and surgical margin were found to be influential factors. In addition, performance status and lymph node involvement were identified as significantly affecting PFS.

Conclusions: In our study, the authors obtained promising results with IMRT. Performance status, lymph node involvement, and surgery emerged as the primary factors significantly influencing OS.