Association between radiotherapy and overall survival or cancer-specific survival in patients with solitary plasmacytoma of bone at pre-B cell grade: a real-world study using the SEER database

Limited real-world studies have compared radiation therapy (RT) to non-RT for patients with solitary plasmacytoma of bone (SPB). This study investigated the impact of RT on long-term survival outcomes in patients with SPB at the pre-B cell grade within a real-world context. We conducted a retrospective cohort analysis using data from the Surveillance, Epidemiology, and End Results (SEER) database for patients diagnosed with SPB at the pre-B cell grade between 2010 and 2017. Patients were categorized into two groups based on receipt of RT. We used Cox proportional hazards models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) to investigate the value of RT for overall survival (OS) and cancer-specific survival (CSS). Survival curves were generated using the Kaplan-Meier method. A total of 1,922 individuals with SPB at the pre-B cell grade met the inclusion and exclusion criteria. Among these, 1,417 (74%) received RT, while 505 (26%) underwent non-RT. Multivariate Cox regression analysis revealed higher rates of OS (HR = 0.64, 95% CI = 0.55-0.74, p < 0.0001) and CSS (HR = 0.68, 95% CI = 0.56-0.82, p < 0.0001) in patients who received RT. These results remained consistent across sensitivity and subgroup analyses. Analysis of the SEER database suggests that RT is associated with improved OS and CSS and is the primary treatment for patients with SPB at the pre-B cell grade.