1. ¹Regional Centre of Excellence in Palliative Care Western Norway/Institute for Surgical Sciences/Pain Clinic Haukeland University Hospital, N-5021 Bergen, Norway
2. ²Norwegian Knowledge Centre for the Health Services, Oslo, Norway
3. ³Pain Management Unit, Royal National Hospital for Rheumatic Diseases/University of Bath, UK
4. ⁴Pain Clinic, Helsinki University Central Hospital/University of Helsinki, Finland

Correspondence: Dr RF Bell, E-mail: rae.bell@helse-bergen.no

Received 30 January 2006; Revised 4 April 2006; Accepted 10 April 2006; Published online 16 May 2006.

Abstract

This qualitative systematic review of the clinical methodology used in randomised, controlled trials of oral opioids (morphine, hydromorphone, oxycodone) for cancer pain underlines the difficulties of good pain research in palliative care. The current literature lacks placebo-controlled superiority trials. Recommendations for future research are discussed.