The South Australian Cancer Registry: a means of assessing cancer incidence, mortality and case survival

Abstract

In 1977, a Cancer Control and Surveillance Unit was established by the South Australian government. The infrastructure of the Unit was the State's Cancer Registry which was established simultaneously. By 1990, approximately 70 000 invasive cancer cases had been notified to the Registry for a population which had increased from 1 287 550 in 1977 to 1 400 000. In 1990, 2940 cancers were notified in males and 2640 in females. The leading sites in males were the prostate, lung, colon and melanoma of the skin, while in females they were the breast, colon, melanoma of the skin and lung. An increase in age-standardised incidence rates for all cancer sites combined has been documented for the 1977–1990 period. The magnitude of the increase was 7% in males and 12% in females. Meanwhile, there were 1544 male cancer deaths and 1203 female cancer deaths in 1990. Amongst males, age-standardised mortality rates tended to decline in the 1980's, due largely to a reducing age-standardised incidence of lung cancer. By comparison, an increased lung cancer incidence in females contributed to an overall increase of 6% in the age-standardised mortality rate for cancers of all sites combined in this sex during the life of the Registry. During the period 1977–1990 there was a 55% increase in the number of new invasive cancers in males and females combined. Most of this increase can be attributed to the ageing of the South Australian population and to a much lesser degree to population growth. During the same period there was a concomitant increase of 43% in the number of deaths where the underlying cause of death was cancer. Case survival rates are found to be very similar in South Australia to those reported for the United States, with about 51% of cases surviving their cancers 5 years after diagnosis. 5-year survival rates for the diagnostic period, 1983–1990, were generally better than for 1977–1982. The evidence for improved survival was strongest for cancers of the oesophagus, colon, cervix, prostate and testes, and for low-grade and medium-grde lymphomas and chronic myeloid leukaemias. When case survival rates were calculated for childhood tumours, significant improvements were found for acute lymphatic leukaemias and non-Hodgkin lymphomas for the diagnostic period, 1983–1990, when compared with 1977–1982.