is good news and bad news on the front of the cancer war. Overall,
cancer mortality rates are decreasing. Doctors are developing better
treatments for many cancers, and several of the most common cancers
are decreasing, especially lung cancer in white males.
the good news. Bad news comes in two forms. People who survive cancer
treatments are still alive, which is good, but their health and
happiness has been compromised significantly, especially for children
suffering from childhood cancers. Their lives will rarely be fully
other piece of bad news is that some cancers continue to increase
in frequency. More... And increasingly
science points to the fact that only genetic factors cause only
a small percentage of cancers. In other words, "most
cancer is made, not born."
epidemiological studies implicate several endocrine-disrupting compounds
as risk factors for various cancers, for example, breast
cancer. The mechanisms of action are not clear, and the results
are not consistent. Nonetheless, given the inherent biases
in epidemiological studies for finding false negatives in studies
of EDCs, the accumulating data justify concern.
points are especially important to bear in mind. First, most studies
have focused on a relatively small number of compounds, especially
PCBs, DDT (and its metabolites, particularly DDE) and dioxin. Some
commentators have argued that because PCBs and DDT show inconclusive
links to breast cancer, that EDCs in general are not involved in
cancer. That is obviously false logic, often promoted
strongly by industry-funded scientists.
literally no studies (as of August 2002) have performed the most
crucial test of EDC involvement in cancer etiology: a prospective
study of exposure in the womb or at other vulnerable stages in development
in relation to risk, later in life, to cancers. Virtually all studies
look at adult exposures and adult risk. Recent work with dioxin
and breast cancer and with PCBs/DDE
and breast cancer, illustrate the importance of this.
is one additional important point to consider on breast cancer and
DDE, the most common human metabolite of DDT. One established risk
factor for breast cancer is life-time exposure to estrogen. DDE
is an anti-androgen, not an estrogen. On this basis, DDE would not
be expected to be a risk factor for breast cancer. More...
of household pesticides elevates the risk of childhood leukemia.
This association had been noted previously, but this new study (published
in August 2002) strengthens the case both with improved methodology
and also by showing that the window of greatest vulnerability is
exposure in the womb. More...
new study of women exposed to dioxin in the 1976 Seveso, Italy,
chemical plant explosion finds an association between dioxin levels
measured in serum taken immediately after the explosion and breast
cancer risk over the next 20 years. This study is an important move
toward the methodology that will be necessary to confirm or refute
impacts on breast cancer risk of exposure during critical periods
of development. More...
Long Island Breast Cancer Study Project published results in July
2002 which report no association between breast cancer risk and
several organochlorine contaminants measured at the time of diagnosis.
Aspects of the study design severely limit the conclusions that
can be drawn. More...
2001 review of breast cancer epidemiology
a small portion of breast cancer cases can be explained
by known risk factors.
is a crucial need to better define time windows of exposure.
Vulnerability periods correspond to in utero life, as well as
prepubertal period both for girls and boys. In women, perimenopause
may also be particularly relevant." A number of studies indicate
that conditions in utero can influence the risk of breast
cancer later in life.