Aim: To determine if Aboriginal people in NSW were diagnosed with more advanced cancer than non-Aboriginal people.
Methods: All cancers diagnosed in NSW in 2001-2007 were extracted from the population-based NSW Central Cancer Registry and linked to the Admitted Patient Data Collection and Australian Bureau of Statistics death records to identify Aboriginal people. The risks of being diagnosed with localised disease for solid tumours were compared for Aboriginal and non-Aboriginal people by cancer site adjusting for sex, age, year of diagnosis, socioeconomic status and place of residence.
Results: Overall 40.3% of 2,039 cancers in Aboriginal people and 46.6% of 191,954 cancers in non-Aboriginal people were localised at diagnosis. After adjusting for age, sex, year of diagnosis, area of residence and socioeconomic status, Aboriginal people had significantly higher risks of regional or distant spread for head and neck cancer (regional: relative risk ratio 1.89, 95% CI 1.21-2.98; distant: relative risk ratio 3.40, 95% CI 1.85-6.05; p<0.001), relative to localised spread, than non-Aboriginal people. For breast, cervical and prostate cancers and melanoma, the risks of regional or distant spread were also higher for Aboriginal people, but these differences were not statistically significant. For lung, colorectal, upper gastrointestinal tract, other gynaecological, and eye, brain and central nervous system cancers, the risks of regional, distant and unknown spread of cancer were similar for Aboriginal and non-Aboriginal people.
Conclusion: It is common to report that Aboriginal people are more likely than non-Aboriginal people to be diagnosed with more advanced cancer. However we found this to be true for only a few cancer types, most notably head and neck cancers. Differences in spread of disease at diagnosis are unlikely to explain much of the survival differences observed across a wide range of cancers between Aboriginal and non-Aboriginal people in NSW.