Blood cancer incidence, mortality and survival for Māori in New Zealand

Background

Haematological (‘blood’) cancers are a diverse group of non-solid cancers with varying incidence, mortality and survival. While there is some evidence that Māori experience disparities in blood cancer outcomes relative to New Zealand’s majority European population, there is a need for a comprehensive overview of the current state of evidence in this context.

Methods

Blood cancer registrations were derived from the NZ Cancer Registry for the 2007–2019 period (combined blood cancers: 2653 Māori, 20,458 Europeans), and linked to Mortality records. We calculated age-sex-standardised incidence and mortality rates, and conducted cancer-specific survival analysis, for four main categories of blood cancers (leukaemia, Hodgkin lymphoma, non-Hodgkin lymphoma and myeloma) as well as for sub-types of leukaemia non-Hodgkin lymphoma.

Results

We found that Māori are more likely to be diagnosed with (incidence) and to die from (mortality) both leukaemia and myeloma, and similarly likely to be diagnosed or die from Hodgkin and non-Hodgkin lymphoma, compared to Europeans. Māori had demonstrably poorer cancer-specific survival outcomes across most blood cancer types (age-sex-adjusted hazard ratios [HRs], Māori vs European: leukaemia 1.77, 95 % CI 1.57–2.00; Hodgkin lymphoma 1.18, 95 % CI 0.65–2.16; non-Hodgkin lymphoma 1.71, 95 % CI 1.50–1.95; myeloma 1.40, 95 % CI 1.19–1.64).

Conclusion

Blood cancers are a common cancer type for Māori, and we found evidence of disparities in incidence, mortality and survival compared to Europeans. Further research is required to further pinpoint exactly where interventions should be aimed to reduce blood cancer incidence and address survival disparities for Māori.