Cancer case-survival rates for South Australia: a comparison with US rates and a preliminary investigation of time trends.

Five-year relative case-survival rates for all cancers collectively are similar in South Australia (49%) and the United States (50%). This suggests that outcomes of cancer treatment do not vary appreciably between the two populations. There is an indication of higher survival rates in South Australia for melanoma, Hodgkin's disease, multiple myeloma and gastric cancer, but lower survival rates for cancers of the thyroid, corpus uteri, prostate, colon, kidney and lung. The differences in point estimates of the rates were most conspicuous for Hodgkin's disease, multiple myeloma and prostatic cancer. The reasons for a cautious interpretation of these findings are discussed and some possible explanations are suggested. South Australian data point to an upward trend in survival rates between the diagnostic periods 1977-1980 and 1981-1985 for patients with Hodgkin's disease, diffuse large-cell lymphomas, melanomas and cancers of the prostate and rectum.