Introduction PCBs may cause or promote prostate cancer, according to several studies included here. The prostate is a walnut-sized gland in men which makes and stores seminal fluid, a milky liquid that nourishes sperm. Located below the bladder and in front of the rectum, the prostate encircles the upper part of the urethra, which is the tube that empties urine from the bladder. The prostate requires male hormones, like testosterone, to function properly, helping to regulate bladder control and normal sexual functioning.  The High Cost of Prostate Cancer

According to the National Cancer Institute, cancer of the prostate is the most common cancer among American men and the second leading cause of cancer deaths (after lung cancer).  About 189,000 new cases of prostate cancer will occur in the United States in the year 2002, and about 30,200 men will die of this disease.

A man's risk of developing prostate cancer increases with age. Although it can occur at any age, it is most often found in men over the age of 50, and more than 75 percent of tumors are found in men over age 65. For a man who is now 50 years old, his probability of developing a prostate cancer during his lifetime is about 42 percent.  In addition, enlargement of the prostate gland now afflicts eighty per cent of men by the age of seventy in western countries. 

Prostate cancer rates rose 4.4 percent a year between 1973 and 1992, more than doubling the risk in a generation. Since 1992, the incidence has declined slightly, but it is still 2.5 times the rate in 1973. Part of this increase can be explained by better detection, but increased incidence has also been accompanied by an increase in mortality - which better detection cannot explain. (Source: National Cancer Institute)  The World Health Organization predicts there will be a 40% increase in prostate cancers in Europe by 2005. 

The National Cancer Institute estimates the overall annual costs for all cancers at $107 billion: $37 billion for all health expenditures, $11 billion for lost productivity due to illness and $59 billion for lost productivity due to premature death. Prostate cancers are responsible for a significant portion of these costs, and PCBs may be risk factor.

Overall Causes of Prostate Cancer

Inherited predispositions are responsible for 5 to 10 percent of all prostate cancers, according to recent genetic studies. This means 90 to 95% of prostate cancers may be caused by environmental or lifestyle factors. 

Studies suggest that a high-fat diet may increase the risk of prostate cancer.  Is it only coincidental that a high-fat diet is more likely to be contaminated with PCBs, dioxins, furans and other persistent chemicals which accumulate up the food chain linked to fats?

Prostate cancer is about twice as common among African-American men as it is among white American men. It is also most common in North America and northwestern Europe. It is less common in Asia, Africa, and South America.  The likelihood of an environmental pollutant or dietary link to the disease is supported by evidence that when Asian males move from Asia to America their risk of prostate cancer rises rapidly.

According to the American Cancer Society, there is evidence that the development of prostate cancer is linked to higher levels of certain hormones. High levels of male hormones (androgens) may contribute to prostate cancer risk in some men. 

Because men with undeveloped testes and castrated men rarely develop prostate cancer, researchers suspect that sex hormones circulating in the blood might affect prostate cancer. "The evidence has been stacking up to form an alarming picture that paints estrogen [female sex hormone] and testosterone [male sex hormone] as cancer culprits," says ENVIRONMENTAL HEALTH PERSPECTIVES, published by the National Institute of Environmental Health Sciences [NIEHS], a scientific organization that does not use the word "alarming" lightly. (Source: Renee Twombly, "Assault on the Male," ENVIRONMENTAL HEALTH PERSPECTIVES Vol. 103, No. 9 (September, 1995), pgs.802-805.)

Animal studies have found that long-term exposure to the hormone estrogen can induce prostate cancer, because estrogen powerfully influences cell growth, development and other processes.  PCBs are well-known mimics of estrogen and can interact with the same receptor molecules inside the body that estrogen can. 

“Initial scientific evidence demonstrates that increased risk of prostate cancer may be associated with unknown environmental factors,” according to White House spokesmen at the time they announced a major new increase in funding to determine environmental causes of disease, in January, 2000. President Clinton designated $27 million, 56 percent greater than the previous year’s funding level, for the Centers for Disease Control and Prevention (CDC) Environmental Health Lab.

According to the National Academy of Sciences (in 1999), the current literature does not support associations between hormonally active agents such as PCBs in the environment and other hormonally sensitive cancers such as prostate cancer. However, they emphasized that few studies have measured the levels of these chemicals in adult humans in relation to cancer risk, and no studies have been conducted to examine associations between the risk of cancer and exposure to these chemicals during fetal development.

In addition, the U.S. EPA’s Office of Research and Development held an Endocrine Disruptors Workshop with several EPA regions in 2001 which concluded, “We cannot discount the role of endocrine disruption in prostate cancer. Methods and longer term tests are needed to determine endocrine disruption effects on both the population and community level.” 

Even so, the existing evidence is suggestive. The Physicians for Social Responsibility report that, “Male mice exposed to DES, estrogen, or bisphenol A (all hormonally active chemicals) in the womb develop enlargement and inflammation of the prostate. Some also develop what appear to be microscopic malignancies in their genital tract. A recent human autopsy study shows that prostate cancer may develop much earlier than previously realized. This study found that, of 152 men who died of other unrelated causes, all less than 50 years old, 34% had evidence of cancer in their prostates when examined microscopically. Of those less than 40 yrs. old, 27% had prostate cancer. These remarkably high percentages, along with the animal data, suggest that prostate cancer may be yet another malignancy whose foundation is laid early in life, perhaps even in utero (in the womb), but which does not become apparent until later when hormone changes stimulate the dormant cancer to grow.”

Prostate Cancer - Table of Contents:

• Studies Linking Prostate Cancer and PCBs
• Summary of Results
• The Studies
• Glutathione, Prostate Cancer and PCBs
• Insulin-like Growth Factor (IGF) and Prostate Cancer
• Studies Showing PCBs Alter Key Hormone Levels
• Dioxin and Prostate Cancer
• Studies and Summaries
• Dioxin References
• Links to More Information
• References