Background: A systematic review, undertaken according to an initiative to revise European Association for Palliative Care guidelines on the use of opioids for cancer pain, which aimed to analyse analgesic efficacy and side effects of spinal opioids in adult cancer patients previously treated with systemic opioids.
Methods: Search strategy elaborated with MeSH terms and words related to cancer, palliative care, pain, spinal route and opioids. PubMed, Embase and Cochrane assessed in Nov 2009. Studies were analysed and classified according to quality of evidence and strength of recommendation.
Results: Out of 2939 abstracts, 44 articles were selected (nine randomized controlled trials (RCTs), two non-randomized cohort studies, 28 uncontrolled prospective studies, and five case series). Relief of pain and/or side effects were reported in 42 articles; however, there were few studies of high quality design (RCTs) and these studies had methodological limitations that reduced their quality of evidence to very low.
Conclusion: There are few RCTs and these are of very low quality. As a result, they provide weak recommendation for using spinal opioids in adult cancer patients. Further studies are clearly needed.