MONITORING OF OPIOID THERAPY IN ADVANCED CANCER PAIN PATIENTS

Until now, there have not been any parameters to monitor opioid therap y in cancer-patients with pain. In this study, 325 consecutive advance d cancer patients were scheduled for a prospective longitudinal survey . After exclusions, 67 patients were surveyed. All included patients w ere advanced cancer patients with pain that required opioid therapy fo r more than 6 weeks before death. Opioid escalation, symptoms associat ed with opioid therapy, pain mechanism and pain intensity were recoded . indices were calculated to categorize the response to opioids. The o pioid escalation index (OEI) was used to index the mean increase of th e starting opioid dosage, expressed as a percentage or in mg. The leng th of the period of stable dose (MLD) and the effective analgesic scor e (EAS), that is, the analgesic consumption/pain relief ratio calculat ed at fixed intervals, were also used. Patients with a mean visual ana logue scale score (VAS) of less than 4 and regular OEI and EAS were co nsidered responsive; patients with a mean VAS less than 4 but with an OEI more than 5 or increases of more than 100% of EAS when compared to that calculated the week before were considered mildly responsive; an d patients with a mean VAS more than 4 were considered unresponsive. A dvanced age, female gender and previous chemotherapy were all factors reducing OEI. Head and neck cancer was associated with a higher OEI. R egarding the influence of the opioid-related symptoms, an increased OE I was associated with the presence of confusion. Moreover the presence of confusion was associated with neuropathic pain. Neuropathic pain t aken alone, however did not influence this score. Gender-specific canc er, such as breast cancer; influenced the gender differences reported for MLD (significantly longer than that reported for males and other p rimary tumor). Good responsiveness was observed in 28 patients, partia l responsiveness in 33 patients unresponsiveness in six patients. Psyc hological factors were associated with poor pain relief, probably redu cing the patient's compliance. The tools used in this study may be use ful in monitoring the effects of opioid therapy in cancer pain patient s. Simple numbers are easy to compare and make it possible to profile opioid responsiveness ansi differences among patients. (C) U.S. Cancer Pain Relief Committee, 1997.