Between 2007 and 2017, we investigated this cluster of vulvar cancer to:
Find out the extent of the problem
Try to identify why Indigenous women in East Arnhem are disproportionately affected
Improve community and health professional awareness of the problem
Develop better strategies for preventing, diagnosing and treating vulvar cancer in women in the affected communities.
- To confirm our recent finding that a genetic susceptibility to vulvar cancer is responsible for the excess occurrence of this cancer in Arnhem Land.
- To identify the specific genetic variant responsible for this genetic susceptibility.
- To determine the biological mechanism through which this genetic variant operates.
In response to reports from outreach gynaecologists of excess cases of vulvar cancer and its precursor lesion, vulvar intraepithelial neoplasia (VIN), in the East Arnhem (EA) health district of the Northern Territory (NT), an initial epidemiological investigation was undertaken from 2007. This identified evidence of a cluster of vulvar cancer among young (aged less than 50 years) Indigenous women resident in EA, with an incidence rate over 50 times higher than the national Australian rate for the same age group, and the highest identified anywhere in the world.
Subsequently, research undertaken by the Menzies School of Health Research in collaboration with other research institutions and the NT Department of Health has found this cluster to be as an unusually aggressive form of Human Papillomavirus-dependent vulvar cancer. EA Indigenous women treated for vulvar cancer or VIN are more likely to experience a recurrence of the disease following treatment, more likely to experience more recurrences, and have a higher mortality rate than other Northern Territory residents affected with this disease.
While HPV is likely to be involved in the aetiology of vulvar cancer in this population, the very high incidence is not explained by a higher prevalence of vulvar infection with HPV or a particularly virulent strain of HPV. Genetic studies have found evidence of an inherited predisposition to vulvar cancer among EA Indigenous women and results to date indicate that, rather than one or two genetic variants of large effect size, this cluster may be driven by the cumulative burden of multiple rare functional genetic variants. No evidence has been found to suggest that this cluster is driven by other environmental risk factors, including smoking, sexually transmitted infections, immunosuppressive conditions or cultural practices.
More information is available on the Vulvar Cancer Story website.
Implications for policy and practice:
The cluster investigation has included a disease control component throughout, undertaken in conjunction with the Department of Health. Since 2007, the research team has assumed responsibility for several aspects of the disease control response including monitoring the cluster, community engagement, and developing community and clinical education resources. With the end of the research component at the end of 2017, these responsibilities will return to the NT Department of Health.
These research findings have two main implications for disease control strategies:
- While there is evidence that genetic susceptibility is responsible for this cluster of vulvar cancer, a genetic variant suitable for screening was not found. Consequently, genetic testing of women is not possible to identify individuals at excessive risk.
- HPV type 16 was found in specimens of vulvar cancer from the affected women. The current HPV vaccine includes HPV16 and is likely to be protective again vulvar cancer in the affected population.
More detailed recommendations for policy and practice are outlined in our 2017 Report.
- Dr Rebekah McWhirter
- Dr Rebekah McWhirter
2007 - 2017.
- National Health and Medical Research Council (NHMRC)
- Menzies Research Institute Tasmania
- Northern Territory Department of Health
- University of Adelaide
- Monash University
- Royal Adelaide Hospital
- Condon, J. R., Rumbold, A. R., Thorn, J. C., O’Brien, M. M., Davy, M. J., & Zardawi, I. (2009). A cluster of vulvar cancer and vulvar intraepithelial neoplasia in young Australian Indigenous women. Cancer Causes & Control, 20(1), 67-74.
- Rumbold, A.,Tan, S., Condon, J., Taylor-Thomson, D., Nickels, M., Tabrizi, S., et al. (2012). Investigating a cluster of vulvar cancer in young women: a cross-sectional study of genital human papillomavirus prevalence. BMC Infectious Diseases, 12(1), 243.
- Tan, S. E., Garland, S. M., Rumbold, A. R., Zardawi, I., Taylor-Thomson, D., Condon, J. R., & Tabrizi, S. N. (2013). Investigating a cluster of vulvar cancers in young women: distribution of human papillomavirus and HPV-16 variants in vulvar dysplastic or neoplastic biopsies. Sexual health, 10, 18-25.
- Tan, S. E., Garland, S. M., Rumbold, A. R., & Tabrizi, S. N. (2010). Human papillomavirus genotyping using archival vulval dysplastic or neoplastic biopsy tissues: comparison between the INNO-LiPA and linear array assays. Journal of Clinical Microbiology, 48(4), 1458-1460.
- McWhirter, R. E., Mununggirritj, D., Marika, D., Dickinson, J. L., & Condon, J. R. (2012). Ethical genetic research in Indigenous communities: challenges and successful approaches. Trends in Molecular Medicine 18(12), 702-708.
- McWhirter, R.E., Thomson, R.J., Marthick, J.R., Rumbold, A.R., Brown, M.A., Taylor-Thomson, D., Maypilama, E.L., Condon, J.R., & Dickinson, J,L. (2014). Runs of homozygosity and a cluster of vulvar cancer in young Australian Aboriginal women. Gynecologic Oncology, 133(3), 421-6. doi: 10.1016/j.ygyno.2014.03.566. Epub 29/3/2014.
- McWhirter, R.E., Marthick, J.R., Boyle, J.A., Dickinson, J.L. (2014). Genetic and epigenetic variation in vulvar cancer: current research and future directions. Australian and New Zealand Journal of Obstetrics and Gynaecology, 54(5), 397-499 doi: 10.1111/ajo.12241.
- McWirther, R.E. & Condon, J. (2017), A Vulvar Cancer Cluster in Indigenous Women in Arnhem Land: Report 2017, Menzies School of Health Research.