A cancer cluster is an unusual number of cancers occurring during a specific time period among people who live or work together. The impression that a cancer cluster exists usually begins when someone's spouse, neighbour, or friend is diagnosed with cancer. This close contact with cancer often brings an awareness of others who have cancer and a desire to answer the question, "Why?" It is not uncommon for people to suspect the cancer cause is a chemical in the environment.

For information on cancer deaths in Ireland, please contact the Central Statistics Office (CSO).

For information on cancer data in Ireland,  please view our Data & Statistics section.

Increasingly, people are becoming worried about the possible existence of cancer clusters. The Registry takes such claims very seriously, but must be extremely careful examining the results.

Because it is so difficult to tell a true cancer cluster from a random number of cases which appears to be a cluster, we have a protocol for investigating which cancer clusters might be worth investigating more fully. Often, studying much larger groups of people will shed more light on the causes of cancer than studying isolated clusters based on a small area. 

For more information about a particular cancer visit the Data & Statistics section or the Research section of this site. 

For additional information, visit the websites of any of the following organisations: Irish Cancer Society, the National Cancer Institute in the US, or the University of Pennsylvania Cancer Centre.

The main causes of death in Ireland differ very little from one year to the next. The three main causes of death in Ireland are as follows:

• Heart Disease
• Cancer
• Diseases of the Respiratory System

For further information,  please view our Data & Statistics section.

Unfortunately, almost anyone can develop cancer, even children and young adults who lead active, healthy lives. The largest number of cancers occur in the 65+ age group.  Read more in our Data & Statistics section.

To find out more about the different types of cancer and their frequency in Ireland, visit our Data & Statistics section.

It is rarely possible to find the cause of a cancer in an individual, but studies on groups of people with cancer have shown specific risk factors to be associated with specific cancers. This suggests that different types of cancer probably have different causes. These studies also indicate that cancer formation is a multi-step process, and that for most cancers the time from a cancer-causing exposure to a clinically diagnosable cancer averages about 20 years.

In recent times, a new test for prostate cancer, the Prostate-Specific Antigen (PSA) test has become available. This has helped doctors detect prostate cancers much earlier.