Palliative external-beam radiotherapy for bone metastases from hepatocellular carcinoma

The incidence of bone metastases (BMs) from hepatocellular carcinoma (HCC) is relatively low compared to those of other cancers, but it has increased recently, especially in Asian countries. Typically, BMs from HCC appear radiologically as osteolytic, destructive, and expansive components with large, bulky soft-tissue masses. These soft-tissue masses are unique to bone metastases from HCC and often replace the normal bone matrix and exhibit expansive growth. They often compress the peripheral nerves, spinal cord, or cranial nerves, causing not only bone pain but also neuropathic pain and neurological symptoms. In patients with spinal BMs, the consequent metastatic spinal cord compression (MSCC) causes paralysis. Skull base metastases (SBMs) with cranial nerve involvement can cause neurological symptoms. Therefore, patients with bony lesions often suffer from pain or neurological symptoms that have a severe, adverse effect on the quality of life. External-beam radiotherapy (EBRT) can effectively relieve bone pain and neurological symptoms caused by BMs. However, EBRT is not yet widely used for the palliative management of BMs from HCC because of the limited number of relevant studies. Furthermore, the optimal dosing schedule remains unclear, despite clinical evidence to support single-fraction radiation schedules for primary cancers. In this review, we outline data describing palliative EBRT for BMs from HCC in the context of (1) bone pain; (2) MSCC; and (3) SBMs.