Cancer pain and the importance of its control.

In 1985 there were almost 5 million deaths from cancer, and it is estimated that in 2015 there will be over 9 million, of which almost three-quarters will be in developing countries. Seventy to eighty per cent of these patients will experience moderate or severe pain at some stage of their illness and at present most of these will die in pain. This is true in spite of the fact that there is substantial evidence which shows that in as many as 80% of patients with cancer pain it is possible to obtain complete relief with orally administered analgesics, either alone or supplemented with co-analgesic (adjuvant) drugs. Management is based on the three-step analgesic ladder whereby the choice of analgesic (non-opioid, weak opioid, or strong opioid) is determined by the severity of pain. The main reasons for failure to achieve control of pain are inexperience and lack of knowledge of the simple principles of effective analgesic use, and in many countries the non-availability of strong opioid analgesics. The most important advances in management have been the simplification and refinement of analgesic treatment which have made relief of cancer pain more widely accessible to patients. The introduction of controlled-release oral formulations of morphine has had a considerable impact because they are convenient and simple to use. The recent development of a long-acting non-invasive transdermal delivery system for strong opioid administration promises a further step forward in terms of flexibility and convenience for cancer patients.