Alarming Projections Signal Urgent Need for Action

New Zealand is on the brink of a significant increase in stomach cancer cases, with researchers forecasting a nearly 50 percent rise by 2045. This stark warning comes from a groundbreaking study led by experts from Health New Zealand – Te Whatu Ora and the University of Auckland, highlighting not just national trends but deep ethnic and regional disparities that demand immediate attention. As the population ages and grows, the absolute number of annual cases could climb from around 492 today to approximately 725, even as age-standardized rates show a modest decline. This projection underscores the critical role of academic research in shaping public health strategies.

The study, published in the New Zealand Medical Journal, utilized sophisticated age-period-cohort modeling on two decades of cancer registry data. By factoring in historical incidence patterns, demographic shifts, and population projections from Statistics New Zealand, the researchers provide a granular view stratified by ethnicity, sex, age, and Health New Zealand regions. This approach reveals how demographic pressures—particularly an ageing population—will amplify the burden, with cases among those aged 75 and older potentially doubling.

Such detailed forecasting is vital for universities like the University of Auckland, where public health researchers are pivotal in translating data into actionable insights. Their work not only informs policymakers but also trains the next generation of epidemiologists and clinicians equipped to tackle these challenges.

Disproportionate Impact on Māori and Pacific Communities

Ethnic inequities stand out starkly in the projections. Māori cases are expected to surge 96 percent, from 84 to 165 annually, while Pacific peoples face a 93 percent increase from 45 to 87 cases. Asians could see the most dramatic proportional rise at 198 percent (54 to 161), driven largely by population growth, though their age-standardized rates will decline like others. For European/Other populations, numbers remain stable around 309-311 cases, with falling rates.

These trends reflect longstanding disparities rooted in higher baseline risks for Māori and Pacific groups, who experience three to six times the incidence compared to Europeans. Stomach cancer ranks as a top 10 killer among Māori, with five-year survival hovering at just 27 percent—far below national averages. Factors like higher Helicobacter pylori (H. pylori) prevalence, linked to childhood infections in crowded households, play a major role. Additionally, hereditary risks such as CDH1 gene mutations, overrepresented in Māori whānau, contribute to early-onset diffuse gastric cancer.

University of Auckland's Maryann Heather, a senior lecturer in the Section of Pacific Health and co-author, brings expertise in addressing these inequities. Her involvement highlights how higher education institutions are bridging cultural gaps in research, emphasizing culturally safe approaches to prevention and care.

Regional Variations and Service Strain

Geographically, the Northern Region faces the steepest climb at 57 percent (195 to 306 cases), followed by Te Manawa Taki (46 percent), Central (42 percent), and Te Waipounamu (36 percent). Declining age-standardized rates across all regions mask the raw increase in patient numbers, straining endoscopy, surgical oncology, and chemotherapy services.

For instance, the shift toward older patients—projected to account for nearly 50 percent of cases by 2045—will demand enhanced geriatric oncology capabilities. Men will bear a heavier load, with cases rising from 307 to 461, compared to 185 to 263 for women. These insights equip Health New Zealand regions to prioritize resource allocation, a process informed by university-led modeling.

Understanding the Drivers: H. pylori and Beyond

Helicobacter pylori infection, acquired mainly in childhood, is the dominant modifiable cause, fueling chronic inflammation that can lead to gastric cancer over decades. Household overcrowding, more common in Pacific communities, accelerates transmission. The study's diffuse-type predominance in high-risk groups further ties back to this bacterium.

Other contributors include diet, smoking, alcohol, obesity, and environmental exposures, alongside structural barriers like socioeconomic deprivation delaying diagnosis. Hereditary diffuse gastric cancer, linked to CDH1 mutations, adds a genetic layer, particularly for Māori families facing up to 70 percent lifetime risk.

Researchers from Health New Zealand and the University of Auckland stress that while incidence rates may dip due to past public health gains, demographics override this, necessitating proactive interventions.

The Research Methodology: Robust Projections

Employing Poisson generalized linear models with age-period-cohort structure, the team analyzed New Zealand Cancer Registry data from 2001-2022. Categorical variables for sex, ethnicity (prioritized: Māori, Pacific, Asian, European/Other), and region were included, with recency-weighted trends and bootstrap uncertainty intervals (95% UI). Population denominators from Stats NZ enabled precise age-standardized rates using the WHO world standard.

This rigorous, disaggregated approach—novel for gastric cancer in New Zealand—offers policymakers evidence-based forecasts. Academic contributions like those from University of Auckland ensure methodological excellence, fostering collaborations between universities and health authorities.

Implications for Healthcare Delivery

The projected 48 percent case increase translates to heightened demand for specialized services. Surgical volumes for gastrectomies, already regionally variable, must expand, alongside chemotherapy and survivorship care. Older patients will require multidisciplinary geriatric support, amplifying costs and workforce needs.

Universities play a key role here, training oncologists, epidemiologists, and public health specialists. Programs at the University of Auckland, for example, integrate equity-focused curricula to prepare graduates for disparity-driven demands.

Targeted Prevention: H. pylori Screening Pathways

Prevention offers the brightest path forward. The study advocates equity-focused H. pylori test-and-treat programs, potentially population-wide or targeted at Māori and Pacific peoples. Integrating with initiatives like National Bowel Screening Programme, these could include primary care incentives and cultural adaptations.Read the full study here.

Complementary efforts target tobacco, alcohol, and obesity via regulatory measures. Early detection via endoscopy for high-risk groups, plus genetic counseling for CDH1 carriers, could avert many cases.

University of Auckland's Pivotal Role in Cancer Research

As New Zealand's leading research university, the University of Auckland excels in public health epidemiology. Co-author Maryann Heather's Pacific Health expertise exemplifies how faculty drive equity-oriented studies. The Section of Pacific Health fosters community-engaged research, vital for culturally resonant interventions.

This gastric cancer projection aligns with broader university efforts in cancer control, from H. pylori trials to survivorship studies, positioning Auckland as a hub for training researchers addressing Māori and Pacific inequities.

Broader Cancer Control Context

Gastric cancer, though comprising a small fraction of total cases, punches above its weight due to high fatality and inequities. It complements Te Aho o Te Kahu's State of Cancer reports, urging alignment with the New Zealand Cancer Action Plan 2019-2029.Explore the latest State of Cancer report.

Universities must expand interdisciplinary training in oncology, epidemiology, and cultural competency to meet rising needs.

Future Outlook and Calls to Action

While demographic inevitabilities drive rises, targeted prevention could flatten curves for high-risk groups. Policymakers should fund H. pylori pilots, bolster endoscopy capacity, and invest in research training.

For academics and health professionals, opportunities abound in gastric cancer research and clinical trials. New Zealand's universities offer pathways to contribute meaningfully, from PhD programs to faculty roles in public health.

Stakeholders must act swiftly to avert a preventable crisis, leveraging university expertise for equitable outcomes.

Photo by Alexandre Lecocq on Unsplash