Outcomes of SWI/SNF complex‐deficient sinonasal carcinomas in a Southeast Asian cohort

Background SWI/SNF complex‐deficient sinonasal carcinomas are rare, genetically distinct, and aggressive entities. Methods SMARCB1 and SMARCA4 immunohistochemistry was retrospectively performed on a cohort of undifferentiated, poorly differentiated, and poorly defined sinonasal carcinomas. Survival outcomes were compared between SMARCB1/SMARCA4 (SWI/SNF complex)‐deficient and ‐retained groups. Results Eight SWI/SNF complex‐deficient (six SMARCB1‐deficient, two SMARCA4‐deficient) cases were identified among 47 patients over 12 years. Triple‐modality treatment was more frequently utilized in SWI/SNF complex‐deficient carcinomas than in SWI/SNF complex‐retained carcinomas (71.4% vs. 11.8%, p = 0.001). After a median follow‐up of 21.3 (IQR 9.9–56.0) months, SWI/SNF complex‐deficient sinonasal carcinomas showed comparable recurrence rates (57.1% vs. 52.9%, p = 0.839), time‐to‐recurrence (7.3 [IQR 6.6–8.3] vs. 9.1 [IQR 3.9–17.4] months, p = 0.531), and overall survival (17.7 [IQR 11.8–67.0] vs. 21.6 [IQR 8.9–56.0] months, p = 0.835) compared to SWI/SNF complex‐retained sinonasal carcinomas. Conclusion Triple‐modality treatment may improve survival in SWI/SNF complex‐deficient sinonasal carcinomas.