In 2010 the most common invasive cancer in Ireland was non-melanoma skin cancer. Dr Harry Comber discusses the most common cancers and mortality rates in Ireland spanning 16 years
Dr Harry Comber, Director, National Cancer Registry of Ireland, Cork
In 2010, 32,694 new cancers were diagnosed in Ireland (see Table 1). Most of these (26,372; 80%) were invasive and almost all the rest were in situ cancers of skin, breast and cervix. By far the most common invasive cancer was non-melanoma cancer of the skin. There were more than 2,000 new cases each year of four other cancers – prostate, breast, lung and colorectal. These four sites accounted for 40% of all invasive cancers, excluding non-melanoma skin cancer.
(click to enlarge)
In the 18 years between 2010 and the start of national cancer registration in 1994, the number of invasive cancer cases diagnosed each year has risen by 53%, about 3% a year.
For some cancers the rate of increase has been even greater: prostate cancer cases have increased almost threefold, from 1,096 to 2,998 a year; melanoma and hepatobiliary cancer by 120%; and breast cancer by 70%. Much of the overall increase in numbers has been due to demographic change, and the increases in age-adjusted incidence rate have been more modest – 13% overall, about 0.8% a year.
However, the age-adjusted incidence rate of prostate cancer has increased by about 100% and the female breast cancer incidence rate by about 20%. The rapid rise in prostate cancer incidence is almost entirely due to PSA testing of asymptomatic men, while the increase in breast cancer incidence is comprised of an underlying increase in risk coupled with the effects of the recent roll-out of the national screening programme.
Extrapolation of the current trends in incidence suggests that the number of invasive cancers will rise to about 38,000 by 2020 and to about 55,000 by 2030, with obvious implications for services. Most of this increase will be due to demographic change.
Cancer mortality
There were 8,161 deaths due to cancer registered in 2010, 30% of the total.1
Lung cancer was the most common cause of death – 23% of the total for men and 18% for women – and has now overtaken breast cancer as the cancer most likely to cause death in women. The next most common causes of cancer death were, in men, colorectal and prostate cancer (12% of the total each) and in women, breast cancer (16% of the total).
Cancer mortality rates have been declining since about 1980, although at a slower rate than overall mortality. This, as well as the ageing of the population, means that cancer deaths are making up an increasing proportion of all deaths (see Figure 1).2
Figure 1. Number of deaths per year 1973-2006, by main cause of death
Overall cancer mortality in Ireland was close to the European average in 2008. Although prostate cancer incidence in Ireland was the highest in Europe, mortality from cancer in Ireland was only 11th-highest in Europe.3 In 2006, cancer cost 120,000 person-years of life, up from 99,000 in 1996.
International comparisons of incidence
Cancer incidence in Ireland was estimated to be the second-highest in Europe in 2008, second-highest for men and fourth-highest for women.3
Prostate cancer incidence in Ireland ranked highest of all 30 European countries and was over 60% higher than the EU average. The high incidence rate in Ireland is almost certainly due to the very large increase in PSA testing here in recent years.
Female lung cancer incidence was high in Ireland relative to other European countries, ranking fifth of 29 countries. However, male lung cancer incidence, although higher than female, was lower than the EU male average and ranked 21st.
Recent figures on smoking rates across Europe have shown Irish females to be ranked sixth highest and males 22nd highest of the 25 EU countries –rankings very similar to the lung cancer incidence.4
Female and male colorectal cancer incidence were both ranked eighth-highest of the 30 European countries. Irish female colorectal cancer incidence was 15% higher than the EU average, while the male incidence was 11% higher.
Female breast cancer incidence in Ireland ranked fourth-highest of the 30 European countries surveyed.
The comparatively high incidence rate in Ireland may be linked to the development of organised screening here in recent years.
Survival
Cancer survival has improved significantly since 1994 for both males and females (see Figure 2). Survival at five years after diagnosis has increased from 39% for males diagnosed in 1994-1997 to 55% for those diagnosed in 2005-2008.
Figure 2. Five-year relative survival by sex and year of incidence(click to enlarge)
Similar improvements in survival were seen for females; from 47% for those diagnosed in 1994-1997 to 55% for those diagnosed in 2005-2008.
Although some of the improvement for men can be attributed to a change in case-mix, with a fall in the proportion of cancers with poor survival (such as lung) and an increase in those with better survival (such as prostate), most of the overall improvement has been due to a real increase in survival for all the common cancer sites.
The largest relative increases were in prostate cancer and lung cancer, both of which showed a 38% increase in five-year survival between 1994-1997 and 2005-2008 (see Figure 3).
Figure 3. Five-year relative survival by site and year of incidence
However, despite the overall improvement in survival in Ireland, figures published this year by the OECD showed that, of 20 developed countries studied, Ireland had the poorest survival for cervical cancer.
Ireland also had the second-poorest for colorectal cancer (ahead of the Czech Republic) and the third-poorest for female breast cancer (ahead of the Czech Republic and Slovenia).
It is not clear if the OECD data is fully comparable between countries and more definitive figures on survival will be produced by the EUROCARE 4 collaboration in 2012.
A number of projects are currently underway in Europe to examine possible reasons for the large international differences in survival.
Prevalence and cancer survivors
At the end of 2009, 173,000 people who had been diagnosed with invasive cancer since 1994 were still alive. This represents eight prevalent cases for each incident case. Excluding non-melanoma skin cancer, there were 103,000 prevalent cases at the end of 2009, seven per incident case. The commonest prevalent cancer was breast cancer, at 22% of the total.
With an expected doubling in incident cases in the next 20 years and the continuing increase in overall survival, we can expect a very large increase in the number of cancer survivorsCentral Statistics Office. Vital Statistics. Fourth Quarter and yearly Summary 2010, Stationery Office, Dublin 2011.
References
Central Statistics Office. Vital Statistics. Fourth Quarter and yearly Summary 2010, Stationery Office, Dublin 2011.
Kaiser S, Gommer AM, (RIVM). Percentage of daily smokers age 15+ in the EU-27, EUPHIX, EUphact. Bilthoven: RIVM, EUphact\ Determinants of health\ Health behaviours\ Smoking, (http://www.euphix.org/object_document/o4754n27423.html) Accessed 29/12/11
(click to enlarge)
