C3 researchers have been investigating disparities in cancer incidence, mortality and survival between Māori and non-Māori across cancer types since 2010.
This work continues to highlight gaps in evidence and identify the critical factors to achieve more equitable outcomes.
Visit our Māori and cancer disparities publications in Our Archive
Blood cancers
In 2023-2024 we conducted a national study of blood cancer incidence, mortality and survival, with an emphasis on the burden for Māori and how this compares to that for Europeans in Aotearoa New Zealand.
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 joined-up, comprehensive overview of the current state of evidence in this context.
In our study we calculated age-sex-standardised incidence and mortality rates, and conducted cancer-specific survival analysis, for four main categories of blood cancers:
- Leukaemia and sub-types
- Hodgkin lymphoma
- Non-Hodgkin lymphoma and sub-types
- Myeloma
Colon cancer
There is evidence that Māori have worse survival rates from cancer (including colon cancer) compared with non-Māori. Moreover, this difference appears at least partly due to factors occurring after diagnosis. We identified a need to assess the extent to which survival from colon cancer varies between Māori and non-Māori independently of stage at diagnosis, and also to identify post-diagnosis factors contributing to this inequality, including differences in treatment and follow-up.
We examined cancer treatment in a cohort of New Zealanders with newly diagnosed colon cancer and compared Māori (indigenous) and non-Māori patients in terms of surgery, adjuvant therapy, and palliative therapy. New Zealanders with colon cancer were identified from the cancer registry (n=642). Information was obtained about their cancer and treatment from health care records, pathology records, and the national mortality database. We compared characteristics important to survival between Māori and non-Māori. We also conducted survival analyses assessing the impact of disease, patient, treatment, and healthcare factors on survival disparities.
Liver and stomach cancer
Liver cancer
Our work spans from liver cancer prevention through to access to treatment, with a focus on understanding and explaining differences between Māori and non-Māori.
Liver cancer is the seventh most-common cancer globally, with 906,000 cases occurring in 2020. Liver cancer is also among the most deadly cancers, having the third highest cancer mortality rate globally (behind lung and breast cancer) and with 830,000 deaths in 2020. This high mortality rate is driven by poor survival among those diagnosed with liver cancer, of whom approximately 40% will survive one year post-diagnosis, and 20% will survive five years.
Liver cancer is one of the top-ten most common cancers among New Zealand’s Indigenous Māori population, and one of the top-five most common causes of Māori cancer death. Māori remain substantially more likely to be diagnosed with liver cancer than non-Māori, and less likely to survive once diagnosed.
Stomach cancer
Our work includes identifying the drivers for both the disparities in incidence and survival, including the prevalence and role of H Pylori, and investigating possible interventions to address these drivers.
Stomach cancer is a leading cause of mortality worldwide, accounting for some 650,000 deaths annually. In New Zealand, stomach cancer is a particularly important disease for the indigenous Māori and the Pacific populations, with rates 3-6 times higher than European New Zealanders. Survival from stomach cancer is also worse for Māori. Our work in this area includes identifying the drivers for both the disparities in incidence and survival, including the prevalence and role of H Pylori, and investigating possible interventions to address these drivers.
Visit our liver and stomach cancer publications in Our Archive
Testicular cancer
Testicular cancer is by far the most common cancer among young men. Our work has identified an unusual ethnic inequality in testicular cancer, whereby Māori men suffer 80 per cent higher rates than European/Other men. This is in stark contrast to other international contexts, where it is the European / White population that suffer the highest rates of this disease.
As part of a HRC Eru Pomare Career Development Award, Dr Jason Gurney led a programme of research in both testicular cancer and a congenital condition known as cryptorchidism (undescended testis), which is a risk factor for the development of testicular cancer. In addition, the C3 Research Group continue to collaborate with the International Agency for Research on Cancer (IARC) in Lyon on global trends in testicular cancer.