The term cancer encompasses a wide range of diseases including common illnesses such as lung cancer and colon cancer, as well as more esoteric ones, such as the acute leukaemias. Malignant disease is widely prevalent and, in the Western world, is second only to cardiovascular disease as the cause of death.
Cancer is thus not one illness and the treatment therefore involves multidisciplinary teams including surgeons, radiotherapists, medical oncologists, specialist nurses and palliative care teams. Treatment is given with either curative or palliative intent.
Many advances have been made in the last 30 years, both in treatment and in understanding the biology of the disease. Molecular biology techniques have opened up new possibilities of determining the aetiology of cancer, at least at the molecular level. However, for most cancers, the consequences of the molecular changes have not been determined.
Although in most patients the cause of the illness remains unknown, various factors have been identified as being associated with the development of malignant disease. Usually the cause is multifactorial, although the association of smoking with lung cancer is so strong that it almost certainly represents a single cause-andeffect relationship.