||PCB Human Health Risks||
PCBs may cause Kidney Cancer,
The International Agency for Research on Cancer has concluded that there is some evidence to link long-term, high-level, PCB exposure in occupational settings to an increased incidence of cancer, particularly liver and kidney cancer. This conclusion is based on studies of humans exposed to PCBs contaminated with polychlorinated dibenzofurans, which may play a role in cancer development. (Source: Environment Canada) Most PCBs are contaminated with furans.
Renal cell carcinoma is the most common kidney cancer; it accounts for more than 90% of malignant kidney tumors. Less common types of tumors include transitional cell carcinomas, Wilms’ tumors, renal sarcomas, renal cell adenomas, renal oncocytomas, and angiomyolipomas. In the United States, renal adenocarcinoma — cancer of the kidney — accounts for about 3% of all adult cancers.
The American Cancer Society estimates that there will be about 30,800 new cases of kidney cancer (18,700 in men and 12,100 in women) in the United States in the year 2001, and about 12,100 people (7,500 men and 4,600 women) will die from this disease. These statistics include both adults and children, and include renal cell carcinomas as well as transitional cell carcinomas of the renal pelvis. Renal cell carcinoma is the most common type of kidney cancer in adults while Wilms' tumor is the most common type of kidney cancer in children.
Risk Factors for Kidney Cancer
Lifestyle risk factors for Kidney Cancer include: smoking, obesity, certain medications (diuretics), and consumption of well-cooked meat. Also, workplace exposures to asbestos, cadmium (a type of metal), certain clothing dyes, some chemicals used in the rubber industry, and organic solvents, particularly trichloroethylene. Men have approximately twice the risk of women (which may be related to higher smoking and occupational exposures in men). Kidney cancer tends to affect adults aged 50-70 years.
Some people inherit a tendency to develop certain types of cancer. The DNA that a person inherits from their parents may have certain changes that account for this tendency to develop cancer. Sometimes, these DNA alterations also occur during fetal development inside the mother’s womb.
Some changes in chromosomes and genes that cause kidney cells to become cancerous are inherited, and cause the conditions leading to hereditary (inherited) kidney cancer. Sometimes these changes are not inherited, and occur after birth, possibly due to cancer-causing chemicals or other unknown causes. (Source: The American Cancer Society)
There has been a steady increase in the incidence of renal cell carcinoma that is not explained by the increased use of diagnostic imaging procedures. Mortality rates have also shown a steady increase. From 1950 to 1989, the incidence of kidney cancers increased 109.4%, and the death rate increased 28%. For another period, from 1973 to 1998, the incidence increased 47%.
An important study appearing in the New England Journal of Medicine on July 13, 2000, confirmed what many suspected -- inherited genetic factors make only a minor contribution to susceptibility to most cancers. The researchers found that for all cancers combined, identical twins -- sharing 100 percent of their genes--developed the same disease about 10 percent of the time. For breast, prostate, and colon cancer, both twins had the disease 14-30 percent of the time. In other words, most cancer is made, not born. (References: see Links)