This review did not identify any convincing evidence that a particular type of intervention directed either at patients or professionals could improve cancer pain management. Its overall reliability is uncertain given problems identified in the conduct of the review.

To identify the main barriers to adequate cancer pain management and evaluate interventions that aim to overcome them. This abstract is concerned with the interventions only.

The authors searched PubMed from 1986 to April 2007 for studies published in English. Keywords used were documented in the article. Reference lists of relevant articles and an author's personal library were searched.

To be included in the review of interventions, studies had to be randomised controlled trials (RCTs) of interventions to overcome published barriers to cancer pain. The main outcome measures were patients' pain intensity, patients' or professionals' knowledge or barriers, adherence to analgesics and adequacy of pain treatment as measured with the pain management index (PMI). Interventions to overcome patient-related barriers were centred around patient education. Programmes varied in type, content and duration. Interventions to overcome professional-related barriers were concerned with professional education, pain assessment and pain consultation/protocol.

The authors stated neither how the papers were selected for the review nor how many reviewers performed the selection.

Methodological quality of the RCTs was assessed with published criteria and an additional assessment of study power.

The authors did not state how the validity assessment was performed.

The effect of the intervention on pain in each RCT was calculated as the difference in the decrease in pain intensity in relation to baseline between the intervention and control group. A clinically relevant effect was defined as a difference in the reduction of pain intensity of 30% or greater than or equal to 2 points on a 0 to 10 scale. If insufficient data on pain intensities were reported, the authors contacted the first author of the included trials in order to gain access to the source data. All data on statistical significance were retrieved from the original papers.

The authors did not state how many reviewers performed the data extraction.

A narrative synthesis was conducted with trials grouped according to whether they addressed patient or professional-related barriers.

Seventeen RCTs were included in the review of interventions to overcome barriers to pain management. The total number of patients was not stated. Most trials used small sample sizes with no assessment of study power. Most trials on professional education and pain assessment did not report the effect of the intervention on patients' pain.

Interventions to reduce patient-related barriers, patient education (11 RCTs): Five of 11 RCTs found a statistically significant decrease in pain with respect to baseline between the interventions and control group, but in only two of these could the effect be classed as clinically significant. Eight of 10 trials reported a statistically significant improvement in knowledge about cancer pain and its management in the intervention group as compared to the control group. Three of six trials reported a statistically significant improvement on patients' adherence to analgesics in the intervention group compared to the control group.

Interventions to reduce professional-related barriers (six RCTs): Two RCTs provided professional education to nursing staff. One did not present relevant outcomes; the other found statistically significant increases in nurses' knowledge, but not on other outcomes. Two RCTs evaluated the effect of pain assessment. One did not result in improved pain control and the other was not reported in full. In two RCTs on pain consultation, patients' pain decreased statistically significantly, but the adequacy of pain treatment did not change.

We were unable to identify any interventions that unequivocally demonstrated clinically relevant improvements in patients' pain using the outcome measurements and criteria selected for this review.

The review question was broadly defined in terms of population and intervention and more closely defined for outcome measures and study designs. It was unclear whether all relevant studies were identified given that studies needed to be published and in English and keywords used in the search were limited. It was unclear whether more than one reviewer was involved in the processes of study selection, quality assessment and data extraction, which raised the possibility of bias and error. There was a lack of detail on patient demographics, which made it difficult to assess any potential relevance of these to the results found. A narrative synthesis was appropriate given the diversity of the interventions identified. The overall reliability of the review is uncertain given the problems identified.

Practice: Not stated

Research: The authors stated that future research should focus on a multilevel approach of structural identification of cancer-related pain, implementation of a multidisciplinary protocol to improve the quality of pain treatment and education of patients and their relatives to enhance their involvement in the pain treatment. International consensus about the primary outcome measurement in pain research was urgently needed.

Not stated.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.