The primary end-point of the study is the proportion of cancer patients with severe pain. Secondary end-points include opioids administered in the wards, knowledge in pain management, quality of pain management. We plan to recruit about 500 cancer patients from ten hospital wards. This sample size should be sufficient, after appropriate statistical adjustments for clustering, to detect an absolute decrease in the proportion of cancer patients with severe pain (the primary end-point) from 20% to 9%.