The first year counts: cancer survival among Indigenous and non‐Indigenous Queenslanders, 1997–2006

Abstract

OBJECTIVE: To examine the differential in cancer survival between Indigenous and non-Indigenous people in Queensland in relation to time after diagnosis, remoteness and area-socioeconomic disadvantage. DESIGN, SETTING AND PARTICIPANTS: Descriptive study of population-based data on all 150,059 Queensland residents of known Indigenous status aged 15 years and over who were diagnosed with a primary invasive cancer during 1997-2006. MAIN OUTCOME MEASURES: Hazard ratios for the categories of area-socioeconomic disadvantage, remoteness and Indigenous status, as well as conditional 5-year survival estimates. RESULTS: Five-year survival was lower for Indigenous people diagnosed with cancer (50.3%; 95% CI, 47.8%-52.8%) compared with non-Indigenous people (61.9%; 95% CI, 61.7%-62.2%). There was no evidence that this differential varied by remoteness (P = 0.780) or area-socioeconomic disadvantage (P = 0.845). However, it did vary by time after diagnosis. In a time-varying survival model stratified by age, sex and cancer type, the 50% excess mortality in the first year (adjusted HR, 1.50; 95% CI, 1.38-1.63) reduced to near unity at 2 years after diagnosis (HR, 1.03; 95% CI, 0.78-1.35). CONCLUSIONS: After a wide disparity in cancer survival in the first 2 years after diagnosis, Indigenous patients with cancer who survive these 2 years have a similar outlook to non-Indigenous patients. Access to services and socioeconomic factors are unlikely to be the main causes of the early lower Indigenous survival, as patterns were similar across remoteness and area-socioeconomic disadvantage. There is an urgent need to identify the factors leading to poor outcomes early after diagnosis among Indigenous people with cancer.