Clinical characteristics and prognostic factors of patients with solitary plasmacytoma: a multicenter retrospective study.

BACKGROUND

Solitary plasmacytoma (SP) is a rare plasmacytoma. Research on clinical characteristics and prognostic factors for SP is very limited.

OBJECTIVE

This study aimed to evaluate the clinical attributes and prognostic indicators for individuals afflicted with SP.

DESIGN

We retrospectively analyzed the clinical parameters and survival data of 49 patients diagnosed with SP from three centers between the year 2009 and 2024.

METHODS

The Kaplan-Meier curves were constructed to compare the survival outcomes. The independent risk factors were determined based on the Cox proportional hazards model.

RESULTS

Among the 49 patients with SP, 30 (61.2%) were classified as solitary bone plasmacytoma (SBP), while 19 (38.8%) had solitary extramedullary plasmacytoma (SEP). Anatomically, SEPs predominantly localized to the upper aerodigestive tract (47.4%), whereas SBPs exhibited a predilection for the axial spine (30.0%) and appendicular long bones (20.0%). Survival analysis revealed significantly reduced progression-free survival (PFS) in the SBP cohort compared to SEP patients (p = 0.0002), though no statistically significant difference in overall survival was observed between groups (p = 0.1012). Radiotherapy in conjunction with surgery or chemotherapy did not substantially enhance the outcome of the patients with SP. Multivariate Cox regression analysis identified SBP subtype (hazard ratio (HR) = 0.068, 95% confidence interval (CI): 0.008-0.537, p = 0.011) and elevated Ki67 expression (HR = 4.545, 95% CI: 1.005-20.542, p = 0.049) as independent prognostic factors for inferior PFS. Notably, SBP patients with Ki67 expression exceeding 35% demonstrated the poorest clinical outcomes.

CONCLUSION

The prognosis of patients with SBP was poorer than that with SEP. Patients with SBP exhibiting Ki67 expression exceeding 35% had the poorest outcome.