The test is known as AMAS (anti-malignant antibody in serum). More than 4,000 double blind studies of the accuracy of this test have shown that it has a 99 percent sensitivity. In England, the National Health Service has purchased the test to use as a screening tool for women who have abnormal mammograms as a possible alternative to a breast biopsy.

• PESTICIDE CONCENTRATION IN FATTY TISSUES: It may be that we should be measuring concentrations of organochlorines in fatty tissues to predict who will be at risk for breast cancer.

A 1987 pilot study of 50 women in Connecticut showed that concentrations of PCB, DDE and other pesticides were 50 to 60 percent higher in the fatty tissues of women with breast cancer. (Archives of Environmental Health, Mar/Apr/92).

Dr. Mary Wolff, an epidemiologist at the Mount Sinai Medical Center in New York who led the study, told NOW reporter Megan Williams that the results of the study surprised her.

"This is the first new evidence that could be a clue about the rising breast cancer rates," she says, "I've been a sceptic all along about the environmental concerns, but I keep getting proven wrong (NOW, Dec 2/92)."

When levels of DDT, lindane and BHC in Israeli dairy products (previously 100 to 800 percent greater than in U.S. dairy products) were reduced, the breast cancer death rate also fell dramatically by an estimated 20 percent.

Starting in 1994, the National Institute for Environmental Health Sciences in the U.S. will fund a much larger study measuring levels of DDT and its metabolites in the blood samples of 15,000 women, and try to correlate them with breast cancer rates.

So What Do The Studies Show So Far ?

Even for doctors, there is a confusing maze of studies, all with varying interpretations. Some doctors believe this information is difficult for women to understand. However, I believe that a woman can make a more informed decision about routine mammograms if she understands fully the complexity of the issues involved.

Favourable Studies

THE HIP STUDY: In 1963 The Health Insurance Plan of New York (HIP) and The National Cancer Institute launched the first large scale study of breast cancer screening. It involved two groups of women of 30,000 each. The study group received physical exams plus annual mammograms for four years and the control group, their usual medical care only. The follow-up on all these women continued for 23 years until 1986.

This is one of the major studies in the field, along with a Swedish study, and both are considered scientifically valid because they have the proper control group to compare the results of the study group to (known as a randomized study).

The HIP study showed a 30 percent reduction in the breast cancer death rate in women aged 40 to 64 in the first ten years of the study. Eighteen years into the study, the reduction in breast cancer death rate dropped to 25 percent. The reduction in death rate was greatest for women over 50 years of age.

The HIP study was not designed to study various age groups, only the overall effect of mammography and physical exam on the death rate from breast cancer. Nonetheless, many interpretations of this study have been made. The value of screening mammography for women under 50 was little, but a small decrease in the death rate from breast cancer occurred 18 years after the study.

In this large study, not only mammography but breast examination by a trained medical practitioner contributed to the detection of breast cancer. In fact, 33 percent of breast cancers were only seen on mammography, and 45 percent found only through breast examination.

Another important finding of the study was that breast cancer found in the study group was at an earlier stage and had less incidence of spread to the lymph glands under the arm than in the control group.