A cancer cluster is a
disease cluster in which a high number of
cancer cases occurs in a group of people in a particular geographic area over a limited period of time.
[Cancer Cluster FAQ](_blank)
Centers for Disease Control and Prevention, National Center for Environmental Health, Division of Environmental Hazards and Health Effects.
Historical examples of work-related cancer clusters are well documented in the medical literature. Notable examples include: scrotal cancer among
chimney sweeps in 18th century
London;
osteosarcoma among
female watch dial painters in the 20th century;
skin cancer in farmers;
bladder cancer in
dye
A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution an ...
workers exposed to
aniline compounds; and
leukemia and
lymphoma in chemical workers exposed to
benzene.
[Cancer Facts](_blank)
. National Cancer Institute. U.S. National Institutes of Health.
Cancer cluster suspicions usually arise when members of the general public report that their family members, friends, neighbors, or coworkers have been diagnosed with the same or related cancers. State or local health departments will investigate the possibility of a cancer cluster when a claim is filed.
In order to justify investigating such claims, health departments conduct a preliminary review. Data will be collected and verified regarding: the types of cancer reported, numbers of cases, geographic area of the cases, and the patients clinical history. At this point, a committee of medical professionals will examine the data and determine whether or not an investigation (often lengthy and expensive) is justified.
In the U.S., state and local health departments respond to more than 1,000 inquiries about suspected cancer clusters each year. It is possible that a suspected cancer cluster may be due to chance alone; however, only clusters that have a disease rate that is statistically significantly greater than the disease rate of the general population are investigated. Given the number of inquiries it is likely that many of these are due to chance alone. It is a well-known problem in interpreting data that random cases of cancer can appear to form clumps that are misinterpreted as a cluster.
A cluster is less likely to be coincidental if the case consists of one type of cancer, a rare type of cancer, or a type of cancer that is not usually found in a certain age group. Between 5% to 15% of suspected cancer clusters are
statistically significant
In statistical hypothesis testing, a result has statistical significance when it is very unlikely to have occurred given the null hypothesis (simply by chance alone). More precisely, a study's defined significance level, denoted by \alpha, is the p ...
.
Examples

Some of the larger or more well known cancer clusters include:
* At least 700 cases of
clear cell carcinoma
Clear-cell carcinoma, also known as clear-cell adenocarcinoma and mesonephroma, is an epithelial-cell-derived carcinoma characterized by the presence of clear cells observed during histological, diagnostic assessment. This form of cancer is classi ...
caused by the prenatal exposure to
diethylstilbestrol in the US in the mid-1900s.
* The
Camp Lejeune water contamination
The Camp Lejeune water contamination problem occurred at Marine Corps Base Camp Lejeune in Jacksonville, North Carolina, from 1953 to 1987. During that time, United States Marine Corps (USMC) personnel and families at the base bathed in and ing ...
incident in which multiple chemicals were found in drinking water. The CDC found that marines stationed at the base had a 10% higher rate of cancer deaths than those stationed elsewhere.
See also
*
Biostatistics
Biostatistics (also known as biometry) are the development and application of statistical methods to a wide range of topics in biology. It encompasses the design of biological experiments, the collection and analysis of data from those experime ...
*
Cancer Alley
*
Cancer epidemiology
*
Cuzick–Edwards test
*
Environmental racism
* ''
Fooled by Randomness''
*
Incidence
*
Risk assessment
Broadly speaking, a risk assessment is the combined effort of:
# identifying and analyzing potential (future) events that may negatively impact individuals, assets, and/or the environment (i.e. hazard analysis); and
# making judgments "on the ...
* ''
Toms River: A Story of Science and Salvation''
*
Toxicology
Toxicology is a scientific discipline, overlapping with biology, chemistry, pharmacology, and medicine, that involves the study of the adverse effects of chemical substances on living organisms and the practice of diagnosing and treating expos ...
References
External links
Pub Med - latest standards for evaluating cancer clustersNational Institute of Environmental Health Sciences (NIEHS)
{{Portal bar, Medicine
Spatial epidemiology
Medical statistics