Testicular cancer is the most common cancer in young men. While relatively rare compared to other cancers, rates of testicular cancer are increasing rapidly over time in all developed countries, including New Zealand.
The causes of testicular cancer remain obscure, but the condition cryptorchidism – failure of the testes to permanently descend – remains one of the only known risk factors. Recent work by the Cancer and Chronic Conditions (C3) research group has shown ethnic disparities in testicular cancer incidence, whereby the indigenous Māori population exhibit significantly higher rates than New Zealand European, Asian or Pacific Island populations (Sarfati et al., 2010). This finding is contrary to trends in other countries, where the White population generally exhibit the highest rates of testicular cancer.
In 2012/13, the Cancer and Chronic Conditions (C3) research group conducted a Cancer Society of New Zealand-funded study into rates of undescended testes – a condition known as cryptorchidism – among the entire population of children (~300,000) born between 2000-2010. The study found that rates of this condition followed very similar ethnic patterning as observed for testicular cancer – whereby Māori boys were more likely to suffer cryptorchidism than any other ethnic group (Gurney et al., 2013). Our findings strengthen the likelihood that the principal factors responsible for ethnic differences in testicular cancer incidence occur prenatally.
Leading directly on from this work, the Cancer and Chronic Conditions (C3) research group is embarking on a new programme of research – with Dr Jason Gurney leading this work via a Health Research Council Eru Pomare Post-Doctoral Fellowship. The first objective of this Fellowship is to detail the epidemiology of testicular cancer in New Zealand, including tumour type and sub-type and how these compare between ethnic groups.
The culmination of Dr Gurney’s Post-Doctoral Fellowship will be the development and implementation of two case-control studies – one which aims to identify the key risk factors in the development of testicular cancer, and another which aims to identify the key risk factors in the development of cryptorchidism. Both studies will focus on those risk factors that might plausibly explain our unusual ethnic patterns in disease incidence – since by understanding the factors that are causing this ethnic difference, we may be able to better understand the factors that cause the development of these conditions in general.
- Cancer Society of New Zealand, Wellington Division (Testicular Cancer and Cryptorchidism study).
- Health Research Council of New Zealand (Dr Gurney’s Eru Pomare Post-Doctoral Fellowship, entitled: Testicular Cancer in Māori men: What is driving the disparity?)
Testicular cancer in New Zealand: A mystery to be solved:
Hear Dr Jason Gurney talking about the mysteries of testicular cancer aetiology, and the unique opportunity that we have in New Zealand to answer some fundamental questions about this disease.
Gurney J, Sarfati D, Stanley J. Obscure etiology, unusual disparity: the epidemiology of testicular cancer in New Zealand. Cancer Causes and Control 2015;26:561-69.
Gurney J, Stanley J, Shaw C, Sarfati, D. Ethnic patterns of hypospadias in New Zealand do not resemble those observed for cryptorchidism and testicular cancer: evidence of differential aetiology? Andrology; In Press.
Gurney J, Sarfati D, Stanley J, et al. Do ethnic differences in cryptorchidism reflect those found in testicular cancer? The Journal of Urology 2013; 190, p1852-1857.
Sarfati D, Shaw C, Blakely T, et al. Ethnic and socioeconomic trends in testicular cancer. International Journal of Cancer 2010; 128, p1683-1691.
University of Otago:
- Jason Gurney; University of Otago, Wellington
- Diana Sarfati; University of Otago, Wellington
- James Stanley; University of Otago, Wellington
- Caroline Shaw; University of Otago, Wellington
- Tony Merriman; University of Otago, Dunedin
- Melissa McLeod; University of Otago, Wellington
- Bridget Robson; University of Otago, Wellington
- Richard Edwards; University of Otago, Wellington
- Lis Ellison-Loschmann; Massey University, Wellington
- Jonathan Koea; Waitemata District Health Board, Auckland
- Rodney Studd; Capital & Coast District Health Board, Wellington
- Steve Kenny (Tipene); Cancer Society of New Zealand, Wellington