Effects of spinal human beta-endorphin in cancer patients

Eleven cancer patients suffering from chronic pain treatable only with high doses of oral morphine, were treated with 3 mg of human Beta-Endorphin (BE) via a polyvinyl 18 G catheter placed intrathecally (6 pts) or peridurally (5 pts). Pain was evaluated by the visual analogue scale of Scott-Huskisson (VAS) before the administration of BE and at different times thereafter, until the end of analgesia. Blood and/or CSF samples were collected 15, 60, 120 and 360 minutes after the administration of the peptide. BE concentrations were measured by radioimmunoassay, after separation and identification by high pressure liquid chromatography. Statistical evaluation was carried out by means of Pearson's correlation test. The analgesic effect after BE administration was not consistent and only two had complete pain relief. There was no correlation between plasma and/or CSF BE concentrations and pain relief (r = 0.12, p = 0.49, NS and r = -0.34, p = 0.21, NS). Side effects in patients treated intrathecally were restlessness (3 pts), anxiety (3 pts), headache (2 pts), nausea (1 pt), vomiting (2 pts), drowsiness (2 pts), confusion (2 pts), respiratory depression (1 pt). Side effects in patients treated peridurally were nausea (1 pt), vomiting (2 pts), headache (2 pts). We can conclude that spinal administration of BE is of little value in cancer patients.