Neuropathic bone metastases

Neuropathic pain is defined as pain arising as a direct consequence of a lesion or disease affecting the somatosensory part of the nervous system. Several validated instruments exist for its diagnosis and for assessment of response to treatment. Neuropathic pain is common in cancer patients, and may occur as a consequence of bone or soft-tissue metastases in the vicinity of nerve(s), although there is debate about the mechanism. There are limited data on the use of radiotherapy to palliate neuropathic pain of malignant origin in general, and due to bone metastases in particular. One randomized trial comparing a single 8 Gy with 20 Gy in five fractions for neuropathic bone pain (Trans Tasman Radiation Oncology Group, TROG 96.05) found no statistically significant difference in outcomes between the arms, and response rates were of similar magnitude to those observed for localized bone pain. However, further research will be required to determine whether higher doses are more effective.Daniel Roo