AU - Thaler HT

AU - Friedlander-Klar H

AU - Lapin J

AU - Portenoy RK

TI - OPIOID RESPONSIVENESS OF NEUROPATHIC CANCER PAIN: COMBINED ANALYSIS

OF SINGLE-DOSE ANALGESIC TRIALS (MEETING ABSTRACT)

AB - AB - Neuropathic pain resulting from damage to the central or peripheral nervous system is common

in cancer patients (pts). Controversy exists about the opioid responsiveness of this type of pain. Some

clinicians have suggested that these pains may be inherently resistant to opioid analgesia; others have

postulated that the neuropathic mechanism may relatively diminish the analgesic response. To assess these

hypotheses, we performed a combined analysis of the results from 4 controlled single-dose analgesic trials

performed from 1978 to 1982, with morphine or heroin at high and low doses. Analgesic response was

assessed serially over a 6-hr interval using a visual analog scale and was summarized as a total pain relief

(TOTPAR) score. A total of 194 pts with chronic cancer pain were included; there were 482 administrations

of study drug. Median age was 52 yr (20-79). Information about characteristics of pts' pain recorded at the

time of study was reviewed independently by 2 experienced pain clinicians who grouped each case according

to inferred pain mechanism (neuropathic, nociceptive or mixed) and the degree of confidence in the inferred

mechanism (definite vs probable/possible). When initial groupings differed, they were rereviewed with a

third investigator and disagreement was resolved by consensus. Cases were grouped as follows: nociceptive

pain only (n=210), neuropathic pain only (n=51) and mixed (n=221). Analgesic responsiveness was

evaluated comparing TOTPAR scores using the Student's t-test. TOTPAR for the entire group was not

predicted by the specific drug (morphine vs heroin), but the dose (high vs low) was a significant predictor of

TOTPAR. Placebo TOTPAR response was estimated at 5.1, significantly less than the mean observed with

any group. The primary analysis for the study compared analgesic response of pts having any neuropathic

component with those with only nociceptive pain. Results are presented in a table. In a covariate analysis

that adjusted for prior opioid exposure and other prognostic factors, the opioid responsiveness of

neuropathic pain was significant and was less than that of purely nociceptive pain. These data support the

postulate that opioid responsiveness is a continuum and that it is diminished by the neuropathic mechanism

AD - Pain Service AD - Dept. of Neurology AD - Memorial Sloan-Kettering Cancer Center AD - New

York AD - NY 10021 UI - 92682059

SO - Proc Annu Meet Am Soc Clin Oncol 1992;11:A1330-A133