|
The results of a new study
suggest that high levels of specific PCBs may be linked to breast cancer.
Some persistent environmental
contaminants that accumulate in the body of women with age and are similar
in structure to dioxin may be a risk factor for breast cancer.
The findings also highlight
the importance of additional research on the possible link between environmental
contaminants that can mimic hormones or alter hormone metabolism and the
risk of breast cancer.
PCBs, or polychlorinated biphenyls,
are a class of chemicals with a variety of industrial and commercial applications.
Because of concerns about the health effects of the chemicals, PCBs were
banned in the US and Canada two decades ago. The chemicals still linger
in the environment and are present in the food chain, particularly in
fatty foods.
During the past decade, there
have been many studies of the possible link between exposure to PCBs and
an increased risk of breast cancer. Most studies did not detect a link
between high levels of the chemicals and breast cancer, but most of the
studies looked at overall levels of PCBs, not individual chemicals.
Researchers examined the relationship
between breast cancer risk and 14 individual PCBs in 314 women with breast
cancer and a "control" group of 523 healthy women.
Levels of two PCBs -- PCB 118
and PCB 156 -- were linked to a 60%
to 80% greater risk of breast cancer, the researchers report.
This relationship was more pronounced in premenopausal women.
The study also found that women
with high levels of a combination of three PCBs that mimic the cancer-causing
chemical dioxin -- PCBs 105, 118 and 156 -- were about twice as likely to
have breast cancer. These chemicals are known as mono-ortho PCBs. This
risk was also greater in premenopausal women.
The results may indicate a
relation between dioxin-like compounds and breast cancer risk. The study
is the second large study to suggest a link between mono-ortho PCBs and
breast cancer.
American
Journal of Epidemiology April 1, 2002;155:629-635
| 