Effects on cancer patients' health-related quality of life after the start of morphine therapy.

To investigate the effects of morphine on cancer patients' health-related quality of life (HRQL), we prospectively studied 40 cancer patients with moderate or severe pain despite treatment with "weak" opioids. The patients were titrated to pain relief using immediate-release (IR) morphine and then switched to slow-release (SR) morphine in the same daily dosages. HRQL was measured by the European Organization for Research and Treatment of Cancer core quality-of-life questionnaire (EORTC QLQ-C30) before the start of morphine (baseline), after stabilization with IR-morphine, and 3 days after start of SR-morphine. The mean titrated daily morphine dosage was 97 mg (range, 60-180). The EORTC QLQ-C30 global health score increased after IR morphine titration (baseline score 40, IR morphine period score 49), but a significant difference from baseline did not persist during the SR morphine period (score 44). The other functional HRQL scores showed no significant fluctuations. After start of IR morphine, two of the HRQL symptom scores increased, nausea/vomiting and constipation, but these changes also did not persist during the SR morphine period. Intensity of pain was associated with a lower level of function and higher intensity of symptoms, but only with relatively small (not higher than 0.44) correlation coefficients. Compared to normative data from the general population, physical function, role function, social function, and global health were impaired in the study patients. The patients also suffered more fatigue, pain, nausea/vomiting, appetite loss, and constipation. In conclusion, in cancer patients with reduced HRQL, the start of morphine therapy had no major influence on aspects of HRQL other than pain.