Comparative effectiveness of kilo- and megavoltage energies in low-dose radiotherapy for painful degenerative musculoskeletal diseases: a systematic review and meta-analysis.

Purpose: This study aimed to assess the impact of different energy levels on the effectiveness of low-dose radiotherapy (LDRT) for treating painful degenerative musculoskeletal diseases, as comparative efficacy data are currently lacking.

Methods: A systematic review was conducted in PubMed, Embase, and the Cochrane Library databases to identify studies with response information on the energy used (kilovoltage [kV] vs. megavoltage [MV]). The primary endpoint was the overall response rate (ORR), and the secondary endpoint was the complete response rate (CRR). Exploratory subgroup analyses included treatment site, study period, study design, country, and dose per fraction.

Results: A total of 33 studies involving 12,143 patients were analyzed. Short-term follow-up (up to 6 months) showed a pooled ORR of 64% (95% CI 46-78%) for kV and of 62% (95% CI 54-70%) for MV. Long-term follow-up (at least 12 months) revealed a pooled ORR of 85% (95% CI 65-95%) for kV and of 69% (95% CI 62-75%) for MV. Subgroup analysis indicated no significant differences in ORR for energy level stratified by treatment site and other factors. Regarding dose per fraction (0.5 Gy vs. 1.0 Gy), comparable ORRs were demonstrated between the two energies. No clinical side effects were noted.

Conclusion: This meta-analysis suggests that the known effectiveness of LDRT in painful degenerative musculoskeletal disease may not depend on the energy used. Additional studies using standardized evaluation methods are warranted to establish consistency and enhance the comprehensiveness of research. Further research is also needed to explore treatment modality selection considering disease-specific biology.