Study shows cancer risk variation between North and Republic

People in the North have a lower risk of developing some cancers than residents in the Republic, a major cross-border survey revealed today.

The study, carried out in electoral divisions over 12 years and prepared by the Cancer Registry at Queen’s University Belfast, and the National Cancer Registry in Cork, involved 18 types of cancer.

Those which were significantly higher for both sexes in the Republic were non-melanoma skin cancer, melanoma, leukaemia, bladder, pancreas, and brain/central nervous system.

The risk of prostate cancer for men, as well as cancer of the oesophagus and cervix for women, was higher in the Republic.

But lung cancer was higher in the North, where the rate for uterus, non-Hodgkin’s lymphoma, and head and neck cancers was also higher among women.

The first ever all-Ireland cancer atlas survey also revealed that lung, stomach, head and neck and cervical cancers were more common in areas of higher unemployment and low levels of degree attainment.

The findings were the same for non-melanoma skin cancer, female breast cancer, prostate cancer and melanoma.

Other findings included:

* Stomach cancer rates were higher in a band running from Dublin to Donegal, excluding the north-east, but including Belfast;

* There was no statistically significant difference in female breast cancer risk between the different parts of the island;

* The risk of diagnosis of prostate cancer was 29% lower in the North. Men in areas with the highest educational attainment had the highest risk;

* The risk of head and neck cancer was greater, by 21%, for women in the North but there was no statistically significant difference for men.

Dr Anna Gavin, director of the Northern Ireland Cancer Registry, said the mapping of cancer geographically was hugely important in the quest to understand factors that increase cancer rates and also to provide appropriate treatment and cancer services.

She added: “While it is generally accepted that geographic variations in cancer risk are predominantly the result of factors such as tobacco smoking, alcohol drinking, obesity, diet and sexual behaviour there are also a number of findings which we cannot explain yet, including the band of increased stomach cancer incidence from Donegal to Dublin.”

Dr Harry Comber, director of the National Cancer Registry, said the survey showed major variations, sometimes more than two-fold, in the risk of several cancers, across the island.

He said: “Understanding the reasons for this geographical variation, and taking appropriate action, would reduce the cancer burden significantly in Ireland.

“Areas with unexplained higher than average risk should now 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.”