Retrospective analysis of the effectiveness of volumetric modulated arc therapy half‑body irradiation in palliation of pain in patients with multiple bone metastases.

Bone metastases are the most common cause of cancer-related pain. It has been reported that radiotherapy is efficient in the palliation of pain caused by bone metastases. Half-body irradiation (HBI) is a method of palliative treatment in patients with multiple metastases to bones. The present study aimed to evaluate the efficiency of upper and lower HBI in reducing pain in patients with multiple bone metastases treated with volumetric modulated arc therapy (VMAT) HBI. A total of 22 patients received HBI based on the VMAT technique between July 2018 and July 2020. Treatment plans were subject to a dosimetric analysis. The absorbed doses ranged from 6 to 8 Gy in a single fraction. The patients rated pain on the 11-point (0-10) verbal numeric pain score (VNPS) before irradiation and after 1 month of follow-up. To assess the analgesic effect of HBI radiotherapy, data from 19 patients who attended the follow-up visit were analyzed. Before the treatment, the median VNPS of pain was 5 (IQR, 3-8); after the follow-up period, it was 3 (IQR, 1-4) (P=0.003). The median VNPS of the maximum pain within the last month before treatment was 8 (IQR, 7-10) and after irradiation it was 5 (IQR, 4-7) (P<0.001). The median VNPS of the average pain within the last month before the treatment was 5 (IQR, 4-7); after the treatment, it was 3 (IQR, 2-5) (P=0.003). In conclusion, conformal VMAT-intensity-modulated radiation therapy HBI is an effective method for reducing pain in patients with painful multiple bone metastases. Conformal techniques of radiation allow for the reduction of doses to organs at risk thus potentially reducing the toxicity of treatment.