Sinonasal extramedullary plasmacytoma: A population-based incidence and survival analysis

Background: Sinonasal extramedullary plasmacytoma (SN-EMP) is a rare plasma cell neoplasm. Published literature on this tumor largely consists of case reports and case-series with small sample sizes. This study analyzed population-based data on SN-EMP patients to understand demographic and clinical features as well as incidence and survival trends. Methods: The Surveillance, Epidemiology, and End Results (SEER) database was queried for SN-EMP and other head and neck EMP (HN-EMP) cases from 1973 to 2011. Cases were analyzed to determine patient demographics, initial treatment modality, and survival outcomes. Results: Of 778 patients identified with EMP in the head and neck region, 367 patients had SN-EMP and 411 had other HN-EMP. There was a strong male predilection found, with a male-to-female ratio of 3.65:1 in the SN-EMP group and 1.87:1 in the other HN-EMP group. The majority of the patients presented with localized disease in both SN-EMP (84.4%) and other HN-EMP (81.0%) groups. The most common treatment modality reported in this database was surgery with adjuvant radiotherapy in both SN-EMP (46.3%) and other HN-EMP (38.9%) groups, followed by radiotherapy alone (SN-EMP: 40.7%; other HN-EMP: 34.2%). Five-year and 10-year disease-specific survival rates were comparable between SN-EMP (88.2% and 83.3%, respectively) and other HN-EMP (90.0% and 87.4%, respectively) (p = 0.6016 and p = 0.4015, respectively). Conclusion: This study analyzed the largest cohort of SN-EMP patients to date. There was no statistically significant survival advantage found for any 1 particular treatment modality over other treatment modalities in both SN-EMP and other HN-EMP.