Is Breast Cancer Linked To DDT?

DDT was banned in The United States in 1972 because of the possible health effects on humans and other animals. It may cause cancer in the breast and other organs.

Thirty years later, the debate is still raging about whether banning the use of DDT as a pesticide was a necessary step.

It is still being used in many countries. DDT is one of the most effective tools in fighting the mosquito borne disease, malaria.

Although malaria is not a major problem in the United States, there are many countries where it is a deadly epidemic. Thousands of children under three years old are dying from being bitten by mosquitos that spread this disease.

DDT has been strongly linked to increased breast cancer risk.

The residue of DDT mimics estrogen and tends to be stored in fatty tissue which makes the breast a perfect storage place.

The balance of increased risk of future breast cancer from DDT residues and the immediate benefits of reduction in deaths and suffering from malaria makes banning this chemical difficult.

According to a study of 159 women reported in Occupational and Environmental Medicine, women with breast cancer are five times as likely to have DDT pesticide residues in their blood.

These residues of organochlorines (DDT), contain estrogens the female hormone that has been shown to contribute to higher risk of breast cancer.

The possibility of a link between DDT and breast cancer has attracted controversy, admit the authors, but say that their new study adds to the growing body of evidence for an association between environmental estrogens and the rising incidence of breast cancer.

The authors base their findings on a study of 600 women referred to one hospital in Liége, Belgium for breast lumps between September 1999 and February 2000.

From this group, 159 women were diagnosed with breast cancer and subsequently admitted for the removal of the tumor or the whole breast. The women’s average age of the women who were found to have breast cancer was 54.

Before surgery or drug treatment, the women were tested for total levels of organocholorines (DDT) and hexachlorobenzene (HCB) in their blood.

This was done to ensure that the results would not be affected by weight changes brought about by chemotherapy and radiotherapy. Changes in weight result in altering the levels of fatty tissue where the residue of DDT accumulates.

While DDT was effectively banned for use as a pesticide in the US in 1972, it was used for almost 30 years. Residues from DDT can remain active in body tissues for up to 50 years.

The blood samples from the breast cancer group were compared with those taken from 250 healthy women, matched as closely as possible for age, menopausal status, reproductive history, and smoking habit.

The results showed significant differences between the two groups of women.

Those with breast cancer were more than five times as likely to have detectable levels of DDT (above 0.5 parts per billion) as the healthy women. The breast cancer group was also found to be more than nine times as likely to have detectable levels of HCB in their blood.

The highest levels detected were 20 parts per billion.

Some women’s breast tumors are sensitized to, and sustained by, estrogen, but DDT or HCB levels were no higher for the 102 women in this study who had estrogen sensitive breast cancer.

The authors are quick to point out that while their research does not prove a definitive link between estrogenic pesticide residues and breast cancer, there is plenty of published evidence on the ability of hormones to promote animal and human cancers.

Research has shown that DDT, and its major metabolite DDE, do have estrogenic properties.

Elsewhere on the Web:

Bibliography: DDT, DDE and Breast Cancer Risk

Pesticides & Breast Cancer Risk

Influence of Localized DDT Exposure on Breast Cancer

DDT (dicophane) and postmenopausal breast cancer in Europe

Study Discounts DDT Role in Breast Cancer

April 25 , 2003

Last Updated July 31, 2006