Breast Cancer Risks and Causation

Breast cancer is a disease with many risk factors, so calculating the odds of contracting the disease is not a concrete science; some factors are more important than others, some mitigate or aggravate others, and still some combinations of factors can be more toxic than others. In fact, nearly fifty percent of women who contract breast cancer have no risk factors at all. However, doctors can look at risk factors, if any, and estimate an overall cancer risk. There are several risk factors that increase the relative risk (a comparison of the incidence of breast cancer among women with a given risk factor) of contracting breast cancer, among them are:

1. Age at onset
2. Previous cancers
3. Family History
4. Ashkenazi Jewish
5. Genetic (BRCA)
6. Hormone Therapy (HRT)
7. Weight
8. DES Dosage

The Problem of Risk and Causation

Since breast cancer is prevalent in unexposed women, how do we prove that an individual DES daughter's breast cancer is a result of her DES exposure and that she would not have contracted the disease had she not been exposed? Most DES daughters have not been diagnosed with the disease; therefore DES exposure is not an absolute or direct cause. The link is not as strong as smoking and lung cancer. Nonetheless, we believe that in utero DES exposure predisposes some women and makes them more susceptible to breast cancer as they age.

DES was given to women without any testing on the daughter as a fetus. Not short term, not long term, not human, not animal, not for safety, nor efficacy. In reality the DES daughter was a test animal. This conduct on the part of the DES manufacturers was negligent, careless, and endangered the daughters without any corresponding benefit. In fact, the drug companies knew that DES was a carcinogen - they even warned in their literature that a mother who had breast cancer should not take the drug. But, they did nothing to explore whether the drug passed through the umbilical cord and affected the cellular development of the estrogen receptor cells (breast and reproductive tract) of the baby inside. This borders on criminal conduct. The drug manufacturers have already admitted to their wrongdoing by paying billions to DES daughters for injuries to their reproductive tracts; even though most DES daughters had no side effects. The point is that they put the population at risk - a significant risk of malformation and cancer below the belt and they paid for it. We have pursued them successfully for hundreds of women for over three decades. Now we are on a campaign to compensate DES daughters who have contracted breast cancer.

However, the only epidemiological study published on the subject (Palmer J, Wise L, Hatch E, et al. Prenatal diethylstilbestrol exposure and risk of breast cancer. Cancer Epidemiol Biomarkers Prev 2006;15(8):1509-1514.) shows a doubling of the relative risk of breast cancer to the daughters over forty. That means that if one thousand DES daughters contract breast cancer, half would not have the disease had they not been exposed. The problem is, we don't know which ones would have gotten the disease had they never been exposed. There is nothing in the pathology that specifically differentiates a DES daughter's breast cancer is different from the typical breast cancer. Therefore, if you compensate all one thousand women you would be paying half of them when the disease, at least statistically, was not due to the drug. The law has a problem with this concept.

In dealing with scientific issues of causation, the use of epidemiology is much more than a consideration of statistics alone. There are many supporting criteria which scientists analyze to determine the biological plausibility of causation. These are sometimes referred to as postulates. A list of criteria prepared by Hill51 is most helpful; these are also called "Koch's Postulates." They are:

• Strength of the association between events;
• Consistency of the observed association with previous studies ("reproducibility");
• Specificity of the association - Is the effect unique to the cause;
• Temporality - Does the cause precede the effect;
• Dose response relationship;
• Plausibility;
• Coherence;
• Agreement with experimental evidence; and
• Analogy to similar exposure situations.

When we factor out the other significant risk factors for breast cancer such as obesity, family propensity, smoking, and hormone therapy from the group; the epidemiology improves, but the casual link is not what epidemiologists call "strong".

Aaron Levine & Associates are continuing the research presented by the Palmer study.

**This website should be used as an educational tool only. If you suspect you have symptoms of breast cancer, please contact a licensed physician for diagnosis and treatment.**