Abortions linked to rising rate.

• Position: Breast Cancer

Breast cancer used to be a disease of older women. Screening with mammograms is not recommended under age 40. However, the Journal of the American Medical Association reports a near doubling in the rate of metastatic breast cancer in women age 25-39 since 1976. The rate has been increasing slowly--but steadily--and shows no sign of leveling off, points out Jane M. Orient, executive director of the Association of American Physicians, New York, who adds that, today, young mothers of small children are facing mutilating surgery, debilitating chemotherapy, and even death. Yet, there has been no corresponding increase in older women.

The American Council on Science and Health calls the increase "slight" (from 1.53 per 100,000 to 2.9 per 100,000, which actually is almost double), and suggests it could be explained by better diagnostic tests and staging. However, these are not early cases, and they are occurring before the age of first mammography, insists Orient.

As possible causes, an article in MedPage Today puts forth rising obesity rates, changes in alcohol and tobacco use, and genetics, though tobacco use has not been increasing, nor is there any rationale for an increase in cancer genes.

The obvious--but unmentioned--cause is hormones, declares Orient. Breast cancer generally is hormone sensitive, and often is treated with anti-estrogens. After the Women's Health Initiative, many women stopped taking hormone replacement therapy out of fear of invasive breast cancer.

Yet, since the Sexual Revolution, young women in huge numbers have taken higher doses of hormones than their menopausal sisters--in birth control pills, relates Orient. In 2005, the World Health Organization classified oral contraceptives as class-1 carcinogens, one of about 100 substances found to be "carcinogenic in humans."

The most important cause of a high estrogen level is pregnancy. By the end of the first trimester, estrogen increases by 2,000%, stimulating proliferation of cancer-vulnerable Type 1 and Type 2 lobules. However, by the end of pregnancy, 85% of breast tissue has matured into cancer-resistant Type 4 lobules because of hormones made by the fetal-placenta unit. This is why a completed pregnancy has an undisputed protective effect against breast cancer, affirms surgeon Angela Lanfranchi, director of New...