Proton beam therapy for metastatic liver tumors.

Abstract

The purpose of this study was to investigate the safety and efficacy of proton beam therapy (PBT) for the treatment of metastatic liver tumors. A total of 140 patients with liver metastasis who received PBT were retrospectively investigated. The main primary tumor sites were the colorectum (60) and the pancreas (19). One hundred thirty-three patients (95%) completed treatment. Two patients experienced late adverse effects (rib fracture and cholangitis). The 5-year overall survival (OS) rate was 24%. In the 85 patients with lesions confined to the liver, the 5-year OS rate of was 28%, and in the 55 patients with lesions both inside and outside the liver, it was 16% (P=0.007). Among the patients with lesions confined to the liver, the 5-year OS rate of the 62 patients who received curative treatment was 30%, and that of the 23 patients who received palliative treatment, 23% (P=0.016). Multivariate analysis showed that the treatment strategy (curative and palliative) alone was associated with the OS rate (P=0.02). PBT is a potentially safe and effective treatment for metastatic liver tumors.