Objectives: Solitary plasmacytoma is a rare plasma cell neoplasm with varying outcomes. This large IRB-approved retrospective analysis used the National Cancer Database (NCDB) to assess prognostic factors, treatment patterns, and overall survival (OS) among patients treated at Commission on Cancer–accredited facilities in the United States. Methods: Plasmacytoma patients (N=9427) from 2004 to 2020 were identified using the NCDB, excluding multiple myeloma. Descriptive statistics, Kaplan-Meier curves, and multivariate Cox regression analysis were used to evaluate survival outcomes by primary site, radiation dosage, and treatment modality. SAS version 9.4 was used to analyze the data. Results: Among 9427 patients, solitary plasmacytoma of bone (P-Bone) comprised 73% and extramedullary plasmacytoma (P-EM) 27%. Median OS was 106 months for P-Bone versus 146 months for P-EM ( P <0.0001). Combined radiation therapy and surgery achieved the longest median OS (181 mo) versus surgery alone (137 mo) and radiation alone (116 mo; P <0.0001). OS increased with higher radiation dose: <35 Gy (46.6 mo) to ≥50 Gy (176.4 mo; P <0.0001). Among P-Bone sites, skull/mandible lesions showed the best outcomes (122.3 mo). Radiation doses of 45 to 49.9 Gy predominated across most sites. Conclusions: This real-world study analyzes treatment patterns and overall survival in the largest plasmacytoma database to date. Combined surgery and radiation therapy show improved survival outcomes, emphasizing the need for personalized treatment approaches and the strength of combined modality therapy. Considering the primary bone site and radiation dosage aids prognostic assessment and treatment decision-making, contributing to plasmacytoma management and personalized care.
Saba et al. (Wed,) studied this question.