Australia is well documented as having one of the highest incidence rates of cancer globally. In addition, the burden of disease attributable to cancer is rapidly increasing. Despite this, the CONCORD study in 2008 revealed good news, Australia had one of the highest cancer survival rates globally. The vast array of cancer statistics poses significant challenges, and overdiagnosis and lead time bias complicate the interpretation of changes.
Our aim was to provide summary measures of changes in Australian cancer incidence and mortality since 1987, and to describe the context of these changes.
We used publically available national data on mortality and newly registered cancer cases. We compared expected and observed numbers of cancer deaths and cases diagnosed in 2007, using 1987 as a baseline, for people under 75 years of age.
There were 13,012 (21%) more new cancer diagnoses in 2007 compared to the expected number, had 1987 rates been maintained. Prostate cancer accounted for 10,245 of these new cancer cases and breast cancer accounted for 2,736 new cancer cases. These two cancer types alone accounted for virtually all of the excess cases diagnosed. However, there were 7,827 (28%) fewer observed cancer deaths in 2007 compared to the expected number. Lung cancer accounted for a reduction of 2,154 cancer deaths and colorectal cancer accounted for 1,797 fewer cancer deaths, just over half of the reduction in mortality.
Most of the increased cancer incidence in Australia in 2007, relative to 1987 was due to increases in prostate and breast cancer diagnoses. Debate exists regarding over-detection or bringing forward diagnoses for these two cancer types. Both will overestimate national survival rates. Reductions in mortality are more modest but less controversial. These may be more realistic indicators of progress in cancer programs.