Better pain control with 8-gray single fraction palliative radiotherapy for skeletal metastases: a Bayesian network meta-analysis

External Beam Radiotherapy (EBRT) allows remarkable pain control in patients with skeletal metastases. We performed a Bayesian network meta-analysis comparing the most commonly used radiotherapy regimens for palliative management in patients with skeletal metastases. The main online databases were accessed in October 2020. All randomized clinical trials evaluating the irradiation of painful bone metastases were considered. The following irradiation patterns were analysed and included in the present network meta-analysis: 8 Gy- and 10 Gy/single fraction, 20 Gy/5 fractions, 30 Gy/10 fractions. The Bayesian hierarchical random-effect model analysis was adopted in all comparisons. The Log Odds-Ratio (LOR) statistical method for dichotomic data was adopted for analysis. Data from 3595 patients were analysed. The mean follow-up was 9.5 (1 to 28) months. The cumulative mean age was 63.3 ± 2.9. 40.61% (1461 of 3595 patients) were female. The 8Gy/single fraction protocol detected reduced rate of “no pain response” (LOR 3.39), greater rate of “pain response” (LOR-5.88) and complete pain remission (LOR-7.05) compared to the other dose patterns. The 8Gy group detected a lower rate of pathological fractures (LOR 1.16), spinal cord compression (LOR 1.31) and re-irradiation (LOR 2.97) compared to the other dose patterns. Palliative 8Gy/single fraction radiotherapy for skeletal metastases shows outstanding results in terms of pain control, re-irradiations, pathological fractures and spinal cord compression, with no differences in terms of survivorship compared to the other multiple dose patterns. Level of evidence: I, Bayesian network meta-analysis of RCTs.