Intrathecal and epidural somatostatin for patients with cancer. Analgesic effects and postmortem neuropathologic investigations of spinal cord and nerve roots.

BACKGROUND

The antinociceptive effects of somatostatin (SST) after intrathecal administration in rats and dogs and analgesic effects after intrathecal or epidural administration in humans were described previously. In this study, we seek to determine the efficacy of SST in cancer pain management and its potential neurotoxicity.

METHODS

Eight patients with intractable cancer pain were studied. Pain intensity was assessed by patients on a four-grade scale (severe, moderate, mild, none). Additional analgesic drug requirements before and concomitant with SST treatment were used to evaluate the pain relief and assessed on a four-grade scale (poor, fair, good, or excellent). Spinal cords of five patients were autopsied.

RESULTS

The mean duration of SST treatment was 11.3 days. The mean daily dose was 1,252 micrograms (range 250-3,000 micrograms). In six patients the pain relief was rated "excellent" or "good" and in two patients it was assessed "poor" or "fair". None of the patients demonstrated any evidence of neurologic deficit related to the SST treatment. At autopsy, two patients exhibited a moderate demyelination of some spinal dorsal roots and one patient also had a slight demyelination of the dorsal columns.

CONCLUSIONS

SST administered intrathecally and epidurally was an effective analgesic in patients with terminal cancer. Because the described neuropathologic changes could also be cancer-related or result from chemotherapy or radiation therapy we suggest that further judicious use of SST is justified in this category of patients, if their pain remains unrelieved despite large doses of opioid analgesics.