PCBs and Dioxin May Cause Brain Cancer
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The studies in this section show a possible link between PCBs and dioxin exposure, and the later development of brain cancer. (PCBs are frequently contaminated with dioxins.) Several occupational studies have found significant increases in brain cancer associated with PCBs. Other studies find that children may develop brain cancer due to the parents' earlier chemical exposures.
Currently, the cause of brain cancer in most cases is unknown. Radiation and exposure to vinyl chloride (an odorless gas used in making plastics) are the only proven risk factors. Several other environmental factors are strongly suspected, such as exposure to aspartame (a sugar substitute) and exposure to electromagnetic fields from cell phones or power lines. It is rare for brain cancers to run in families. According to the Abramson Cancer Center at the University of Pennsylvania (Oncolink), certain occupations may increase a person's chance of developing a brain tumor. For example, workers in the oil refining, rubber manufacturing, and drug manufacturing industries have higher rates of certain types of brain tumors.
It is well-established that PCBs damage the human immune system, which may be the mechanism whereby PCBs are linked to brain cancer. (see Immune System Damage due to PCBs) The American Cancer Society reports that people with impaired immune systems have an increased risk of developing lymphomas of the brain or spinal cord. Lymphomas are cancers of lymphocytes, a type of cell of the immune system. Lymphomas usually form in lymph nodes. Primary lymphoma of the central nervous system is less common than lymphoma that arises outside the brain but is increasing in frequency even among individuals without established impairment of the immune system. The cause for this increase is not known; however, PCBs have also been linked to Non-Hodgkins Lymphoma. (see Non-Hodgkins Lymphoma and PCBs)
PCBs may also be a co-factor in the suggestive link between electromagnetic fields (EMF) and brain cancer. In past years, electrical equipment frequently used PCBs in transformers, capacitors, and lubricants. Therefore, electrical and power company workers could have been exposed to both PCBs and EMF.
Unfortunately, PCB contamination is widespread in our food sources, with most people in the world now carrying measurable PCB levels in their bodies.
Brain tumors are considered some of the most lethal and difficult to treat forms of cancer. The American Cancer Society estimates that 17,000 Americans (9,600 men and 7,400 women) were diagnosed with primary brain cancer (including cancers of the central nervous system, or spinal cord) and approximately 13,100 people (7,200 men and 5,900 women) died from this disease in 2002. This was a 50% increase in cases from only ten years ago.
(Primary brain cancer is a cancer that begins in the brain. Other brain carcinomas result from cancer spreading from another part of the body.)
Overall, the American Brain Tumor Association estimates that in 2001, more than 180,000 people (adults and children) were diagnosed with a brain tumor of all types. They estimate that 36,200 people were diagnosed with a primary brain tumor in that year (an incidence rate of 12.8 per 100,000 people).
In children, primary brain tumors account for 25% of all cancers and are the leading cause of pediatric cancer deaths. Central nervous system tumors (those located in the brain or spine) are the most prevalent tumors of childhood, the second leading cancer-related cause of death in children younger than 15 years old. These tumors are the third leading cancer-related cause of death in adolescents and adults between the ages of 15 and 34. After a peak in childhood (generally under 10 years of age), the risk of brain cancer increases with age from age 25 to age 75. Brain tumors are most common among middle-aged and older adults. People in their 60s face the highest risk - each year 1 of every 5,000 people in this age group develops a brain tumor.
According to the National Cancer Institute, the incidence of brain cancer in the United States has increased about 1 percent per year since 1973, and the death rate has increased less than 1 percent per year. The increase is seen mainly in people who are 65 years of age or older. For this age group, both the incidence and death rates have increased rapidly at 3 percent per year since 1973. At this rate, the disease is doubling every 23 years among the elderly. Mortality has increased by 16 percent (Ries et al., 1994) since 1973. For people under age 65, the incidence rates increased 0.5 percent per year while mortality rates have decreased almost 1 percent per year.
Go to:
- Summary of Study Results
- Studies Linking Brain Cancer, PCBs and Dioxins
- References
- Links to More Information
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