Avoidable Causes of Breast Cancer: Samuel S. Epstein, M.D.

CHICAGO, May 16 /PRNewswire-USNewswire/ -- The following is a statement from Samuel S. Epstein, M.D., Chairman, Cancer Prevention Coalition:

The Silent Spring Institute must be warmly commended for compiling very important and well-documented reports on environmental causes of breast cancer, termed "mammary gland carcinogens."

These reports clearly incriminate a wide range of industrial chemicals which have been shown over recent decades to induce breast cancer in standard carcinogenicity tests in rats and mice.

Surprisingly, however, the reports make no reference to unarguable epidemiological evidence on other "mammary gland carcinogens," particularly FDA approved drugs; oral contraceptives; estrogen replacement therapy; and rBGH, a genetically engineered drug, injected in cows to increase milk production.

A long-standing series of studies over the last three decades have clearly incriminated hormonal contraceptives as major risks of breast cancer. These include:

  -- A 1981 study in the British Journal of Cancer reported a nearly four
     fold increased risk in young women who had used oral contraceptives for
     eight years before their first pregnancy.
  -- In 1982, the American Journal of Epidemiology announced that women aged
     35 to 54 who used oral contraceptives before their first childbirth
     tripled their risks of breast cancer.
  -- A 1987 study in the British Journal of Cancer reported that women under
     the age of 45 who had used the Pill for over four years before their
     first full-term pregnancy more than doubled their risk.
  -- A 1988 study published in Neoplasia reported that the risk of breast
     cancer increased with duration of use of the Pill, particularly for
     seven or more years. This risk increased to more than seven fold in
     women with a family history.
  -- In 1988, the Cancer and Steroid Hormone Study, published in
     Contraception, revealed that women who had used oral contraceptives for
     eight years or more, who had never given birth, and who had begun
     menstruating before the age of 13 were at increased risk for developing
     breast cancer before the age of 45. The risk was nearly three fold for
     eight to eleven years of use, and twelve fold for twelve or more years
     of use.
  -- In 1995, a National Cancer Institute study found a strong link between
     the length of time oral contraceptives are used and breast cancer risk.
     A few months of use could increase a woman's risk by 30 percent. An
     over two fold risk was found with ten years of use.

The evidence incriminating estrogen replacement therapy (ERT) as a major risk of breast cancer is also long standing and extensive.

  -- In 1991, an American Journal of Epidemiology article cited eight major
     studies demonstrating up to 80 percent increased risk of breast cancer
     among women using ERT for extended periods.
  -- In 1991, pooled results from sixteen previous studies, published in the
     Journal of the American Medical Association, found that women who used
     ERT for fifteen years increased their risk of breast cancer by 30
     percent. Ten fold higher risks were reported among women with a family
     history of breast cancer.
  -- In 1995, the Harvard Nurses' Health Study confirmed an increased risk
     of 30 to 70 percent for women on ERT.
  -- A large-scale study, based on 60,000 postmenopausal women, published in
     the 1997 New England Journal of Medicine, showed that the use of ERT
     for over 10 years increased breast cancer deaths by 43 percent.

Also surprising is the failure of the report to make any reference to over 20 publications demonstrating up to a seven fold increased risk of breast cancer from consumption of milk from cows injected with the genetically engineered bovine growth hormone rBGH drug, as approved by the FDA. This evidence is detailed by the author and four colleagues in a May 11, 2007 Citizen Petition to the FDA (http://www.preventcancer.com/).

Evidence of these avoidable causes of breast cancer also lends urgent support for current Senate proposals calling for radical reform of the FDA to ensure that drugs are safe as advertised.