Disparities in Cancer-Specific Survival Between Māori and Non-Māori New Zealanders, 2007-2016

Abstract

PURPOSE While cancer survival is improving across most developed nations, those improvements are not shared equally within their population. Using high-quality national data, we have reviewed the extent to which cancer survival inequities are persisting for indigenous Māori compared with non-Māori New Zealanders and the extent to which these disparities are driven by deprivation, comorbidity, and stage of disease. METHODS Incident cases of cancer (2007-2016) were extracted from the New Zealand Cancer Registry and linked to mortality and hospitalization data. Descriptive, Kaplan-Meier, and Cox regression methods were used to compare survival outcomes between Māori and non-Māori. RESULTS Māori continue to have poorer survival than non-Māori for 23 of the 24 most common causes of Māori cancer death, with the extent of this disparity ranging from 12% to 156%. The magnitude of these disparities varies according to deprivation, comorbidity, and stage. Of note, there was a tendency for survival disparities to be largest among those with no comorbidity. CONCLUSION Māori continue to experience substantial cancer survival inequities. These observations are in keeping with reports from previous decades, which suggest that these disparities persist despite heightened attention. Reduction of the cancer burden on Māori and achievement of equitable survival outcomes require us to prevent cancer for Māori where we can, diagnose Māori patients early when we cannot, and once diagnosed, deliver equitable care to Māori patients at each step along the treatment path.