Objective: To investigate the outcomes of radiotherapy with or without surgery during treatment of patients with solitary plasmacytoma of bone (SBP) of the spine.

Methods: Patients diagnosed with SBP of the spine treated with radiotherapy with or without surgery were identified and extracted from the SEER database. Propensity score matched (PSM) analysis was performed to balance patient characteristics between radiotherapy alone and radiotherapy with surgery groups. Patients in different age-groups were stratified and analyzed.

Results: A total of 1275 patients with SBP of the spine treated with radiotherapy with or without surgery were extracted from the SEER database. Before PSM, the unadjusted Kaplan-Meier curve showed that the radiotherapy with surgery group had worse overall survival than did the radiotherapy without surgery group (both P < 0.05), whereas the difference of overall survival was attenuated after PSM. Stratified analysis found that the radiotherapy with surgery group had less progression to multiple myeloma for young patients (age <45 years) with SBP of the spine than did the radiotherapy without surgery group.

Conclusions: The results of our study suggest that radiotherapy with surgery may show less progression to multiple myeloma for younger patients with SBP of the spine.