Neuropsychological performance in cancer patients: the role of oral opioids, pain and performance status

The aim of the present study was to evaluate the possible influence of oral opioids, pain and performance status on some aspects of psychomotor functi on and cognition in cancer patients. One hundred and thirty cancer patients between 40 and 76 years of age were consecutively included in the study. I n order to separate the impact of performance status, pain and oral opioids on neuropsychological functioning the patients were allocated in a cross-s ectional design to five different groups. Group 1 (N = 40), which was consi dered the control group, was characterized by being in Karnofsky Performanc e Status (KPS) A ('Able to carry on normal activity and work. No special ca re is needed'), had no pain and received no oral opioid medication. Group 2 (N = 19) was characterized by being in KPS B ('Unable to work. Able to liv e at home and care for most personal needs. A varying degree of assistance is needed'), had no pain and received no oral opioid medication. Group 3 (N = 19) was characterized by being in KPS B, had pain, but received no oral opioid medication. Group 4a (N = 31) was characterized by being in KPS B, h ad pain and received stable doses of oral opioids. Group 4b (N = 21) was ch aracterized by being in KPS B, had no pain and received stable doses of opi oids. Assessments comprised pain intensity, sedation, opioid doses, time fr om ingestion of last opioid dose to testing and opioid side effects. The ne uropsychological tests used were continuous reaction time (CRT), finger tap ping test (FTT) and paced auditory serial addition task (PASAT). Regarding the neuropsychological tests group 1 was compared with each of the other gr oups and respecting the hierarchy of increasing numbers of stigmatizing fac tors group 1 was compared with group 2, group 2 with group 3 and so forth. Concerning CRT, group 1 performed statistically significantly faster than g roups 2, 4a and 4b. Concerning FTT, group 1 performed statistically signifi cantly faster than groups 3 and 4a. Concerning PASAT, groups 1 and 4b perfo rmed statistically significantly better than group 4a. Furthermore, the pai n-relieved groups 2 and 4b performed statistically significantly better in PASAT than the pain-suffering groups 3 and 4a. We conclude that in cancer p atients the impact of stigmatizing factors (oral opioids, pain and reduced performance status) seems to impair some important aspects of neuropsycholo gical performance, but more specifically our results indicate that (1) the use of long-term oral opioid treatment in cancer patients per se did not af fect any of the neuropsychological tests used in the present study, (2) can cer patients being in KPS B had statistically significantly slower CRT than patients being in KPS A and (3) pain itself may deteriorate the performanc e of PASAT more than oral opioid treatment. (C) 2000 International Associat ion for the Study of Pain. Published by Elsevier Science B.V. All rights re served.