|Frequently Asked Questions about Cancer Clusters
What is a cancer cluster?
- A real or meaningful cancer cluster is a number of the
same type of cancers occurring during a short period of time
among people who may live or work in the same area.
Are cancer clusters common?
- No. Real cancer clusters are extremely rare. There have been
no proven cancer clusters in North Carolina, and only a few around
the United States.
There are five people on my street with cancer; is this a meaningful cluster?
- Not necessarily. We would have to study the situation to determine
if it is a real cancer cluster. Remember, cancer is very
common, especially among older people, and each type of cancer
has a different cause. By chance, a group of people on your block
could have a number of different cancers, but it would not be a
How is a cancer cluster studied?
- We ask several questions: are they all the same type of cancer;
during what period of time did these cancers appear; how old
are the people with cancer; is it a rare cancer? Next we confirm that
the cases are cancer. We see if the number of observed cases is
higher than the number of expected cases.
Finally, we would prepare a report with one of three
- No further study because we see no evidence of a cancer problem
- We will monitor the area because there may be a problem, but the evidence is
- The area will be studied in detail because there seems to be a problem. If
the number of cancer cases was higher than expected, we then
study the relationship between the cancer and its possible causes in
the area. A team would come and study the cancer patients, their lifestyles,
work and home environments.
For information from the National Cancer Institute about cancer clusters, please see: http://www.cancer.gov/cancertopics/factsheet/Risk/clusters.
Central Cancer Registry at (919) 715-4556 with questions about these or
other cancer data in North Carolina.
Page last updated
Friday March 09 2012