Palliative radiotherapy for multiple liver metastases: a retrospective analysis of 73 cases

Background Whole-liver radiotherapy for diffuse liver metastases can improve symptoms and abnormal liver-related blood data. However, whole-liver radiotherapy is uncommonly used in clinical practice in Japan. Therefore, we aimed to clarify palliative radiotherapy outcomes in Japanese patients with liver metastases. Methods We retrospectively reviewed databases in our institution to identify patients treated with radiotherapy (8 Gy in a single fraction) for multiple liver metastases between December 2014 and April 2021. The endpoints included pain response, liver-related blood data and adverse effects. We investigated aspartate transaminase, alanine transaminase, lactate dehydrogenase, alkaline phosphatase, gamma-glutamyl transpeptidase and albumin. The mean values at whole-liver radiotherapy and after 2-4 weeks were compared using the Wilcoxon rank-sum test. Results A total of 73 cases in 71 patients were included. The median clinical target volume was 2118 ml (range, 133-7867 ml). Fifty-seven patients (78%) had finished aggressive treatment at the time of radiotherapy. The median follow-up period was 6 weeks. The pain response rate was 64% (18/28). The mean values of five parameters significantly improved 2-4 weeks after radiotherapy compared to those at baseline: aspartate transaminase (118 vs. 83 U/l P < 0.01); alanine transaminase (84 vs. 61 U/l P < 0.01); lactate dehydrogenase (1351 vs. 1007 U/l P = 0.027); alkaline phosphatase (1624 vs. 1216 U/l P < 0.01) and gamma-glutamyl transpeptidase (663 vs. 450 U/l P = 0.037). No patients experienced radiation-induced liver disease. Conclusions Palliative radiotherapy is efficient and safe in Japanese patients with liver metastases. These findings will help encourage whole-liver radiotherapy use in Japan. Palliative radiotherapy achieved good pain palliation and significant improvement of hepatic blood data for Japanese patients with LM. Moreover, no patients experienced radiation-induced liver disease.