Changes in cancer incidence and mortality in New South Wales

OBJECTIVE: To assess changes in cancer incidence and mortality in New South Wales (NSW) between 1973-1977 and 1988-1992. DESIGN: Descriptive analysis of statutory cancer notifications to the NSW Central Cancer Registry. OUTCOME MEASURES: Age-standardised incidence and mortality rates calculated with the "world" standard population. RESULTS: Overall cancer incidence rose markedly, from 251 to 318 per 100,000 in men and from 202 to 241 per 100,000 in women. The rise was greatest in the 60-and-over age group. Cancer mortality fell marginally in men (from 166 to 162 per 100,000) and did not change in women (100 per 100,000 in both periods). It fell in the under-60 age group, and remained stable or rose in older people. Prostate and breast cancers and melanoma of the skin accounted for about half the increase in incidence. Both incidence and mortality increased significantly (P < 0.01) for melanoma and non-Hodgkin's lymphomas in men and lung cancer in women, and fell substantially for stomach cancer in both sexes, lung cancer in men and cervical cancer in women. Despite increasing incidence, mortality, also fell for testicular cancer in men and rectal cancer in women and for leukaemias in children. CONCLUSIONS: The major factor causing the increased incidence of overall cancer was earlier detection. Altered exposure to risk factors could be identified for only a minority of the changes.