Liver cancer shows striking geographic pattern (Feb. 2012) Census Divisions Alg=Algoma Bra=Brant Bru=Bruce Kent=Chatham-Kent Coc=Cochrane Duf=Dufferin Dur=Durham Elg=Elgin Ess=Essex Fro=Frontenac Grey=Grey Hali=Haliburton H-N=Haldimand-Norfolk Halt=Halton Ham=Hamilton Has=Hastings Hur=Huron Kaw=Kawartha Lakes Ken=Kenora Lam=Lambton Lan=Lanark L&G=Leeds & Grenville L&A=Lennox & Addington Man=Manitoulin Mid=Middlesex Mus=Muskoka Nia=Niagara Nor=Northumberland Nip=Nipissing Ott=Ottawa Oxf=Oxford Peel=Peel Per=Perth Pet=Peterborough P&R=Prescott & Russell PrE=Prince Edward PS=Parry Sound Ren=Renfrew RR=Rainy River SDG=Stormont, Dundas & Glengarry Sim=Simcoe Sud=Greater Sudbury & Sudbury District TB=Thunder Bay Tim=Timiskaming Tor=Toronto Wat=Waterloo Wel=Wellington York=York Liver cancer shows striking geographic pattern (Feb. 2012) Significant variation in male liver cancer rates across geographic areas in Ontario may be partly due to differences in their percentage of immigrants. Toronto, York and Peel have high liver cancer incidence rates as well as the largest immigrant populations in Ontario. Liver cancer incidence rates have been increasing since 1984. A striking geographic pattern in Ontario has revealed that the incidence rates of liver cancer in men are higher in areas with large immigrant populations. These higher rates also occur in Ottawa and Frontenac, despite their smaller percentage of immigrants. This distinctive correlation was exposed when the percentage of immigration was plotted against the liver cancer incidence rate for each census division, and likely occurs in Ontario due to the high number of foreign-born residents that tend to gravitate toward this province. For example, almost half of Toronto’s population is made up of immigrants, many of whom have recently come from countries located in regions known for high rates of liver cancer in men, such as India, China, the Philippines, Pakistan and Sri Lanka.1 One reason for this liver cancer–immigration connection is that these men are exposed to risk factors in their homeland, causing their disease to manifest after they have arrived in Canada. This early exposure combined with later diagnosis may help to shed light on why this illness pattern seems to contradict the “healthy immigrant effect,” which describes the phenomenon of newcomers often being healthier than the host populations of the countries they move to. Although it is relatively rare, liver cancer is rapidly increasing, with its most common risk factors being chronic infection with hepatitis B or hepatitis C. In Ontario, the incidence of liver cancer has grown 4% per year since 1984, which has only been surpassed by the rise in thyroid cancer, and in 2008, liver cancer was the 13th most common cancer diagnosed in Ontario men. This cancer is the third most common cause of cancer death in the world and it occurs more often in men that in women. For more information on infections and cancer, see: Cancer Care Ontario: Perspectives on Infectious Agents and Cancer. Toronto: Cancer Care Ontario 2010 at http://www.cancercare.on.ca/research/researchprograms/resnet/popstudies/. References Ferlay J, Shin HR, Bray F, Forman D, Mathers C and Parkin DM. GLOBOCAN 2008 v1.2, Cancer Incidence and Mortality Worldwide: IARC CancerBase No. 10 [Internet]. Lyon, France: International Agency for Research on Cancer; 2010. Available from: http://globocan.iarc.fr, accessed on 20/Jan/2012. Citation: Cancer Care Ontario. Cancer Fact: Liver cancer shows striking geographic pattern. February 2012. Available at http://www.cancercare.on.ca/cancerfacts. Prepared by staff in Prevention and Cancer Control.