Cancer is a notifiable disease in the Northern Territory as it 'is in all other States. It is the only disease category for which an almost complete coverage of incidence data is available in the Northern Territory. The NT Cancer Registry was set up in 1981 and until 1991 provision of information on new cases of cancer in the Territory was on a voluntary basis. Since 1991, it has been a legal requirement that the Cancer Registry be notified of newly diagnosed cases of cancer.