All-Ireland Cancer Atlas shows major variation in cancer risk by area

The first all-Ireland cancer atlas, published on December 9^th by the National Cancer Registry and the Northern Ireland Cancer Registry, shows major unexplained variations across the island in the risk of most common cancers. The atlas shows that in the period 1995-2007:

• Coastal and urban areas had a significantly higher risk of both types of skin cancer;
• Bowel cancer was more common around Cork city and in a band across the north of the island;
• Lung cancer risk was higher in urban areas—Belfast, Dublin, Derry and Cork—and in the east
• Prostate cancer risk was much higher in the Republic of Ireland than in N. Ireland
  • Stomach cancer risk was highest in a band running from Dublin to Donegal;

The risk of many cancers was related to the level of socio-economic deprivation in the area.

• Lung, stomach, head and neck and cervical cancer risk was higher in areas of high unemployment or low educational attainment, while skin, breast and prostate cancer risk was lower in these areas.
• Cancer risk was higher in more densely populated areas.
• Cancer risk was higher, for many cancers, in areas with a higher proportion of elderly people living alone.

Commenting on the findings in the atlas, Dr Anna Gavin, Director of the N. Ireland Cancer Registry, said “It is generally accepted that geographic variations in cancer risk are predominantly the result of variations in factors such as tobacco smoking, alcohol drinking, obesity, diet and sexual behaviour. Action should be taken to reduce the prevalence of important modifiable risk factors such as tobacco, alcohol, obesity and UV exposure. However, while some correlation between smoking prevalence and smoking-related cancers were detected. Some of the variation for other diseases may also be attributable to health service provision, such as higher levels of breast screening in NI in the 1990s and more prostate specific antigen testing in RoI.”

Dr Harry Comber, Director of the National Cancer Registry commented “Understanding the reasons for geographical variation, and taking appropriate action, would reduce the cancer burden significantly in Ireland. Few of the geographical patterns in cancer risk could be satisfactorily explained by the distribution of known risk factors, and for many risk factors the level of detail available was inadequate for this purpose. Areas with unexplained higher than average risk should be studied in detail and a comprehensive programme of research into already known determinants of cancer risk in Ireland is needed to inform cancer control.”