Abstract
BACKGROUND: Given the rarity of plasmacytoma, large-scale database analysis can provide useful information regarding the clinical presentation and patient-related factors impacting overall survival (OS). MATERIALS AND METHODS: The National Cancer Data Base was queried for patients with plasmacytoma between 2004 and 2013, excluding patients with systemic disease. Plasmacytomas were classified as originating in bone (P-bone), in extramedullary tissue (P-EM), or unspecified. Survival was estimated using the Kaplan-Meier and log-rank test method. We used Cox regression to determine specific outcomes adjusting for demographic, socioeconomic, geographic, facility type, year of diagnosis, and comorbid factors. RESULTS: In total, 6225 patients were identified, of which 61.5% were men. The median age at diagnosis was 64 years (range, 18-90 years), and the median follow-up was 58 months. The primary site of disease was P-bone in 4056 (65.1%) patients and P-EM in 1468 (23.6%), and the remaining 701 patients were P-unspecified. The unadjusted median survival for solitary P-bone was 89 months (95% confidence interval, 82.9-95.0 months), and for solitary P-EM was 117.3 months (95% confidence interval, 108.8 months to not reached). Factors associated with improved OS include younger age, private insurance, higher income, solitary lesion, and lower comorbidity score. Patients with P-bone disease treated at academic facilities had improved OS. Only 65% of patients with solitary plasmacytoma lesions received radiation treatment. Age greater than 75 years and increased distance to treatment facility was associated with a decreased likelihood of receiving radiation. CONCLUSIONS: This is the largest study examining outcomes of patients with plasmacytoma using a large database analysis, revealing unique aspects of P-EM versus P-bone and underutilization of radiation treatment.