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, γ-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 γ-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.

Mu rhythm suppression during the imagination of observed action

Mu wave suppression is thought to accompany the activation of the mirror neuron system which occurs when a human observes or imitates the behavior of others. Our investigation indicates a possible difference in mirror neuron system activation between passive and more active observation as suggested by mu wave activation levels. Participants were asked to observe four different videos each 80 s in duration. Each video was repeated once after a 30 s interval. The first video was of visual white noise and participants were instructed to passively observe the video. This was identified as the Baseline condition and served as a mu activation level baseline. The second video was of simple bouncing balls and the observer was again asked to passively observe the video (Ball condition). The third video was of a moving hand (Observation condition). The forth video was of the same moving hand and participants also imagined executing the observed hand movement (Imagination condition). As hypothesized, the Imagination condition activated the greatest level of mu suppression, while the Ball condition activated the lowest level of mu wave suppression. The Observation condition produced a slightly larger level of mu wave suppression than the Ball condition. This progressive increase in mu wave suppression supports the hypothesis that the activation of the mirror neuron system increases as the level of active observation increases.