Analysis of the Treatment and Survival of Sinonasal Extramedullary Plasmacytoma

Background While extramedullary plasmacytomas are infrequently encountered plasma cell malignancies, most cases occur in the head and neck, with a predilection for the sinonasal cavity. Due to the rarity of this disease, the majority of studies on sinonasal extramedullary plasmacytoma (SN-EMP) are case reports or small retrospective case series. Objective To investigate the impact of patient, disease, and treatment factors on the survival of patients with SN-EMP. Methods The National Cancer Database was queried for all patients with SN-EMP between 2004-2016 (N = 381 cases). Univariate and multivariate analyses were used to examine patient demographics, tumor characteristics, and survival. Results The majority of SN-EMP patients were over 60 years old (57.0%), male (69.8%), and white (86.2%). The most common treatment modality was radiotherapy alone (38.6%), followed by surgery plus radiotherapy (37.8%). Five-year overall survival was 74.0% and median survival was 9.1 years. Accounting for patient demographics and tumor characteristics in a multivariate model, the following groups had worse prognosis: 60 and older (HR 1.99, p = 0.031) and frontal sinus primary site (HR 11.56, p = 0.001). Patients who received no treatment (HR 3.89, p = 0.013), chemotherapy alone (HR 5.57, p = 0.008) or radiotherapy plus chemotherapy (HR 2.82, p = 0.005) had significantly lower survival than patients who received radiotherapy alone. Patients who received surgery with radiotherapy (HR 0.57, p = 0.039) had significantly higher survival than patients who received radiotherapy alone. Conclusion In patients with SN-EMP five-year overall survival was found to be 74.0% with decreased survival associated with a frontal sinus primary site and being aged 60 or older. Patients receiving no treatment, chemotherapy alone, or radiotherapy with chemotherapy was associated with lower survival. Receiving surgery plus radiotherapy was associated with the highest five-year overall survival.