Access to opioid analgesics and pain relief for patients with cancer.

Access to pain relief is a crucial concern for patients with cancer, and remains so at all stages of the illness trajectory. This Review covers the scope of the problem and considers the optimal palliative strategy, mainly through the use of opioids. It also discusses various barriers to effective pain management around the world, including regulatory and attitudinal barriers towards opioids, and the unwillingness of national governments to integrate palliative care effectively in cancer control efforts.