Interviews with patients with advanced cancer--another step towards an international cancer pain classification system.

Purpose: Patients' involvement in the development of assessment tools is recommended, and the European Palliative Care Research Collaborative has adhered to this when developing a shared language for cancer pain, an international assessment and classification system. Study objectives were to investigate how patients ranked the relevance of several previously identified pain domains, to investigate patients' perception of the pain experience and to disclose additional, relevant pain domains for cancer pain classification to those identified in the literature.

Methods: Semistructured interviews with advanced cancer patients treated with opioids were performed and analysed verbatim. Patients scored the relevance of predefined pain domains on an 11-point Numerical Rating Scale.

Results: Thirty-three Norwegian and Austrian patients were included (16 females and 17 males); the mean age was 63 years, and the mean Karnofsky performance score was 65. The ranking of domains was as follows etiology (mean Numerical Rating Scale score, 8.5), duration (8.0), intensity (7.4), coping (7.1), physical (5.9) and psychological functioning (5.8). Sleep was identified as a new candidate domain to include in the system. The patients emphasised consequences of having pain, for example, poor physical functioning and psychological distress.

Conclusions: Previously identified pain domains were confirmed to be relevant to the patients; however, the ranking differed from the experts' ranking. Sleep disturbances may be added as a domain in a future classification system.