Making sense of Stomach cancer Inequities in Aotearoa New Zealand

Abstract

Background

Stomach cancer is an important disease for Māori in Aotearoa New Zealand. Māori are more likely to be diagnosed with stomach cancer than non-Māori and have poorer survival. The higher incidence in Māori can be attributed to differential distribution of risk factors. Cancer survival, though, is an indicator of the access to and quality of cancer care with ethnic differences in survival providing a marker of the equity of health care delivery.

Objectives

To investigate: Quantitative Phase 1. Patient, disease, treatment, health care access and outcome characteristics of a cohort of patients with stomach cancer. 2. Whether there were Māori/non-Māori differences in treatment timeliness, quality and quantity. 3. If differences exist, how these differences contributed to Māori/non-Māori stomach cancer survival. Qualitative Phase 4. What key informants identify as issues for stomach cancer treatment in New Zealand, with a focus on Māori. 5. The interventions key informants identify that may improve access to, and quality of, stomach cancer treatment in New Zealand.

Methods

All Māori diagnosed between January 2006 and December 2008 were identified from the New Zealand Cancer Registry and compared with a randomly-selected equal number of non-Māori. Clinical data were obtained through a clinical notes review. Survival data were obtained from the national mortality database. Characteristics and treatment of Māori and non-Māori cohorts were compared using age- and sex-standardised prevalence rates. Cancer-specific mortality hazard ratios were sequentially adjusted for demographic factors, disease factors, patient comorbidity, and health care access factors to assess their contribution to survival disparities. Fifteen key informant interviews were held to investigate those points of the treatment pathway that the quantitative findings suggested were inequitable for Māori.

Results

172 Māori and 163 non-Māori with stomach cancer were compared. Stage and grade distributions were similar between the ethnic groups. Māori were more likely to live rurally and in highly deprived quintiles, and had higher prevalence of comorbidity than non-Māori. Māori were more likely to be diagnosed with tumours located in the distal stomach (43% Māori, 26% non-Māori, p =<0.05). Māori and non-Māori stage I-III patients received similar rates of surgical resection. Māori were less likely to have surgery performed by a specialist surgeon (38% Māori, 79% non-Māori, p<0.01), and less likely to be treated in a main centre (43% Māori, 83% non-Māori, p<0.01). After adjusting for a range of factors Māori appeared to have 30% poorer survival (Hazard ratio 1.30, 95% CI 0.96-1.76). Key informants indicated that inconsistent delivery of cancer services, especially impacting on smaller, less well-resourced DHBs, was the primary barrier to equitable stomach cancer treatment. Recently implemented health systems initiatives are expected to standardise care nationally, however a range of further interventions, particularly focussed on better addressing regional care, communication between services and comorbidity, were identified.

Conclusion

The findings of this thesis suggest that New Zealand’s health care system delivers better cancer care to non-Māori in a number of respects. Achieving equitable care for Māori will require a variety of interventions along the stomach cancer pathway that combine health system level, health care process level and patient level factors.