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What are Cancer Clusters?

What are Cancer Clusters?

If you spend more than an hour watching late-night television, you have seen the advertisements urging viewers to contact one law firm or another if the viewer has been diagnosed with mesothelioma, ovarian cancer or some other condition. In such ads, it is always alleged that some external agent (asbestos in mesothelioma or talcum powder in ovarian cancer) is responsible for a particular type of cancer. If you watch enough of these advertisements, you will eventually notice that very few, if any, ads mention lawsuits related to what are known as “cancer clusters.”

In today’s post, the environmental pollution cancer lawyer at The Doan Law Firm will discuss what the medical and legal communities mean when they refer to “cancer clusters” as well as how such events are investigated. He will then offer suggestions on how victims of a suspected cancer cluster can protect their legal rights to compensation for their illness and other losses.

What is a “cancer cluster?”

According to the National Cancer Institute, a cancer cluster is “… the occurrence of a greater than expected number of cancer cases among a group of people in a defined geographic area over a specific time period.” Note that this definition requires the presence of three factors:

  1. A greater than statistically expected number of cancer cases. Since cancer is a relatively common disease, the laws of statistics predict that there will instances where cancer can randomly appear in a certain geographic area or among ethnic groups.
  2. A well-defined geographic area. This means that a suspected cluster is limited to a specific area such as a town, a county, or to a geographic feature such as a river valley or watershed.
  3. The suspected cluster must have occurred over a specific time frame. Medical investigators disagree as to how long such a time period must be, but most accept a time period of from 2 to 5 years as being adequate for statistical purposes.

Although not specifically mentioned in the National Cancer Institute’s definition, medical authorities almost always require that the suspected cluster include only identical types of cancer or types that are closely related. As an example, a study could be restricted to only colon cancer or to colon cancer and other cancers of the digestive tract such as stomach and intestinal cancers as a possibly related group of cancer types.

How common are cancer clusters?

Despite what you may have seen on television or at a movie theater, cancer clusters are actually quite rare. The most extensive review of this subject to date was published in 2012. In that study researchers found that:

  • Of 576 cancer cluster investigations conducted over the previous 20-year period, in only 72 of the apparent clusters could an increase in the cancer rate be confirmed.
  • In those 72 confirmed instances of increased cancer occurrences, only 3 clusters could be linked to a possible exposure to a cancer-causing agent.
  • In only one cluster could exposure to a cancer-causing agent be scientifically proven.

In other words, out of 576 suspected cancer clusters, only 1 cluster (< 0.002%) was proven to have been due to a specific environmental cause.

How are suspected cancer clusters investigated?

Almost all suspected cancer cluster investigations begin when an oncologist (a doctor who specializes in treating cancer) notices a change in the number of patients being treated for a specific type of cancer. When his or her suspicions are aroused, the oncologist will submit the available evidence for evaluation by an independent expert. Most investigations of suspected cancer clusters are conducted by the federal Environmental Protection Agency and the Centers for Disease Control and Prevention, with the assistance of local and state public health departments.

In order to proceed with a further investigation, the following criteria must be met:

  1. The number of confirmed cancer victims must exceed the number that could be reasonably predicted to occur based on statistics.
  2. The cases must be found only within a certain area and to have occurred within a specific time frame.
  3. There must have been a common source of a known or suspected cancer-causing agent to which all the victims were exposed.
  4. The known or suspected must be detectable in the victim’s body or by the presence of its known byproducts.
  5. All other potential causes of cancer (e.g. a family history of cancer or tobacco use) must be excluded or, at a minimum, be taken into consideration.

Based on the above, it is easy to see why there are so few scientifically confirmed cancer clusters. Although the scientific definition of cause and effect is very demanding, the legal definition of cause and effect is quite different.

How we investigate cancer cases

In the above section, unless all the criteria are satisfied it is impossible to arrive at a firm yes or no answer. In law, such questions are decided on the basis of the preponderance of evidence.

Preponderance of evidence simply means that all factors are considered as a whole, and the case is decided on the basis of which side presents the most likely chain of events that led to a certain contention. Thus, the legal definition of “proof” is much less rigorous that its scientific counterpart.

In cancer cases, we strive to prove three things to the court:

  1. The victim was diagnosed with cancer.
  2. The victim had been chronically (repeatedly) exposed to something that had the potential to cause the victim’s cancer.
  3. Those not exposed to the same cancer-causing agent or substance did not develop cancer. Therefore, exposure to the suspected cancer-causing agent was the likely cause of the victim’s cancer and those responsible for that exposure are liable for the consequences of the victim’s disease.

This, of course, is a very basic overview of the topic of cancer clusters as well as individual cancers that occur outside that formal definition. Regardless of the circumstances, if you or a family member have reason to believe that you were exposed to some agent in the environment that caused cancer to develop, we invite you to contact the environmental pollution cancer lawyer at The Doan Law Firm to arrange a review of the facts in your case and a discussion of the legal options that may be available to you and your family.

When you contact our firm, you case review and first consultation with our environmental pollution cancer lawyer are always free and do no obligate you to hiring our firm. Should you decide that you would like us to represent you in court, we are willing to assume full responsibility for all aspects of preparing your case for trial in exchange for a percentage of the final settlement that we will win for you.

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