2828 - Clinical and Demographic Characteristics, along with Oncological Outcomes, Following Multimodal Treatment of Sinonasal Carcinoma

Purpose/Objective(s): Sinonasal malignancy comprises < 3% of head and neck cancers. Carcinomas (SNC) are the most common histological type (60-80%). Treatment includes a multimodality approach with surgery, radiotherapy (RT), and chemotherapy. The study aimed to assess clinco- demographic profile and treatment outcomes in SNC patients, treated at our institute from 2018- 2023.

Materials/Methods: Patients with biopsy-proven SNC were included in this retrospective analysis. The primary endpoint was to evaluate the correlation between untreated nodal disease and regional failures. Both progression-free survival (PFS) and overall survival (OS) were identified as secondary endpoints. PFS was defined from the date of diagnosis to the date of disease progression or death. OS was defined from the date of diagnosis to the date of death from any cause. Time-to-event data was evaluated using the Kaplan -Meier method.

Results: A total of 66 patients with SNC were included in the study. The median age at diagnosis was 50 years (IQR=41-61). The population consisted of predominantly males (3:1 ratio). The maxillary sinus was the most commonly involved site (60.6%), followed by the nasal cavity (10.6%). Among the carcinomas, squamous cell carcinoma (56.1%) was the most common subtype, followed by adenoid cystic carcinoma (21.2%). The mean tumor size was 4.8 centimeters (cm, IQR= 4- 6.5). At presentation, regional lymph node involvement was present in 16.7% of patients, and metastatic disease was observed in 6.1%. The majority of patients (74.2%) were diagnosed with stage IV disease. Curative intent treatment was decided at baseline for 50 patients (75.8%). Induction chemotherapy was offered for tumor down-staging in 13.6% of patients. Surgical excision was performed in 51.5% of patients, with 23.5% receiving adjuvant chemoradiation (CTRT) and 44.1% receiving adjuvant RT alone. Resection status was R0 in 37.5%, R1 in 25%, and R2 in 37.5%. Radical CTRT was administered in 12.1% of patients. In the curative treatment group, 5 patients (10%) had baseline lymphadenopathy. Among them, neck was addressed either by surgery or RT in 3. Out of 45 patients (90%) with no lymphadenopathy, 13 received elective neck treatment, either by surgery or RT. Regional failure was reported in none. Median follow-up was 30.2 months (IQR= 21- 60.8). In the curative group, 5-year OS was 85.9% (95%CI= 68.7- 93.9) and PFS was 67.1% (95%CI= 46.8- 81.1). The disease progression was local in 11 patients (34.7%), regional in one (2%), and distant in 6 (6%). In the palliative group, 64.7% received RT alone, and 35.3% received CTRT. The median OS was 15.5 months (95%CI= 4.5- 19.8) and the median PFS was 5.2 months (95%CI=1.6- 15.3).

Conclusion: Histological diversity exists within SNC. In addition, advanced stage at presentation, and anatomical proximity to critical neurological structures make the treatment of SNC challenging. Regional failures are uncommon and lymph node treatment can be restricted to patients with baseline nodal involvement.