The ladder and the clock: cancer pain and public policy at the end of the twentieth century.

The origins of the WHO Cancer Pain Relief Program (the Analgesic Ladder) and its research basis in two very different research traditions, one at Memorial Sloan-Kettering Cancer Center in New York, the other at St. Christopher's Hospice in London, are discussed. The Sloan-Kettering group emphasized precise relative differences in analgesic effects of various drugs, whereas Twycross at St. Christopher's used patient well-being as the crucial benchmark. Despite these differences, both traditions presented evidence of the safe and effective use of strong opioids for cancer pain relief, in a setting of individualized attention and close physician monitoring. The success and limitations of the Ladder as a global health policy are briefly addressed.