Objective: To assess trends in cancer incidence and survival for Indigenous and non-Indigenous Australians in the Northern Territory.
Design: Retrospective analysis of population-based cancer registration data.
Setting: New cancer diagnoses in the NT, 1991–2012.
Main outcome measures: Age-adjusted incidence rates; rate ratios comparing incidence in NT Indigenous and non-Indigenous populations with that for other Australians; 5-year survival; multivariable Poisson regression of excess mortality.
Results: The incidence of most cancers in the NT non-Indigenous population was similar to that for other Australians. For the NT Indigenous population, the incidence of cancer at several sites was much higher (v other Australians: lung, 84% higher; head and neck, 325% higher; liver, 366% higher; cervix, 120% higher). With the exception of cervical cancer (65% decrease), incidence rates in the Indigenous population did not fall between 1991–1996 and 2007–2012. The incidence of several other cancers (breast, bowel, prostate, melanoma) was much lower in 1991–1996 than for other Australians, but had increased markedly by 2007–2012 (breast, 274% increase; bowel, 120% increase; prostate, 116% increase). Five-year survival was lower for NT Indigenous than for NT non-Indigenous patients, but had increased for both populations between 1991–2000 and 2001–2010.
Conclusion: The incidence of several cancers that were formerly less common in NT Indigenous people has increased, without a concomitant reduction in the incidence of higher incidence cancers (several of which are smoking-related). The excess burden of cancer in this population will persist until lifestyle risks are mitigated, particularly by reducing the extraordinarily high prevalence of smoking.