Clinical Features and Outcomes of Plasmacytoma in the United States: Analysis Using the National Cancer Data Base

Introduction

Plasmacytomas comprise approximately 3% of all plasma cell malignancies. There is a paucity of large studies assessing clinical features and outcomes of this relatively uncommon disease. Our objective was to describe the patterns of clinical presentation and survival of plasmacytomas using the National Cancer Data Base (NCDB).

Methods

This is a retrospective study of patients with histologically confirmed diagnosis of plasmacytoma from 2000-2011 using International Classification of Diseases for Oncology version 3 (ICD-0-3) code: 9930. Patients who had bone marrow involvement were excluded from the analysis. Plasmacytomas were grouped into two broad categories: extramedullary plasmacytoma (P-EM) and bone plasmacytoma (P-bone) based on their anatomical locations. Overall survival was analyzed using Kaplan-Meier estimates.

Results

A total of 6,939 patients were included in the study (median age 64 years; range 18-90 years). Approximately 62% of these patients were males and 46% patients were ≥ 70 years. Racial/ethnic distribution of the disease was as follows: 76% Whites, 13% Blacks, 7% Hispanics, and 4% others. The anatomical distribution and survival of patients is depicted in the Table. P-EM comprised 30% of the patients, with remaining 70% presenting as P-bone. Among P-EM, most common sites of presentation were upper aero-digestive tract (41%) and connective/soft tissue (20%). After a median follow up of 65 months, the overall survival of P-EM was significantly better than P-bone (113 vs. 78 months; Figure). Based on outcomes, we can categorize the P-EM patients into 3 groups: good (median overall survival > 120 months: upper aero-digestive tract, lymph nodes, endocrine and digestive system), intermediate (median overall survival 90-120 months: nervous system, eye/orbit, pulmonary), and poor (median overall survival <90 months: connective/soft tissue, cardiac/mediastinum, genitourinary, and hepatobiliary system). Males had better overall survival than females in P-bone (84 vs. 67 months; p<0.0001), but had no significant survival difference in P-EM (109 vs. 116 months; p=0.7). In the P-EM group, median overall survival was worst for Blacks (98 months vs. Whites- 108 months, Hispanics- not reached, others-145 months). Conversely, for P-bone, Blacks had a better overall survival than Whites (Blacks- 99 months, Whites- 72 months, Hispanics- 156, others-84 months). Patients who were treated at an academic center had better overall survival than patients treated at other/community centers both in case of P-EM (130 vs. 108 months) and P-bone (107 vs. 69 months).

Conclusions

This is the largest registry-based study on plasmacytoma in the United States. Plasmacytomas have varied clinical presentation, along with significantly different survival based on sites of presentation, race, sex, and treatment facility. Our study results point toward important differences in disease biology based on location and may aid in assessing prognosis for planning treatment. Table. Anatomical distribution and median overall survival of plasmacytomas.

Table

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Overall survival based on location (P-EM: extramedullary plasmacytoma; P-bone: bone plasmacytoma)

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Overall survival based on location (P-EM: extramedullary plasmacytoma; P-bone: bone plasmacytoma)

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