In the Winter 2005 issue of the Journal of American Physicians and Surgeons comes a controversial article: Induced Abortion as an Independent Risk Factor for Breast Cancer: A Critical Review of Recent Studies Based on Prospective Data (pdf).
Here’s the abstract.
Although many case-control studies, based mostly on retrospective collection of data, have shown a statistically significant increase in breast cancer risk after induced abortion, especially before the first full-term pregnancy (FTP), this risk is denied by the National Cancer Institute and many researchers. The conclusions of ten recent studies based on prospective data collection are cited to buttress this position. These studies are examined in detail, with a focus on methodologic aspects. Collectively, these studies are found to embody many serious weaknesses and flaws, including cohort effects, substantial misclassification errors due to missing information in databases, inadequate follow-up times, inadequately controlled effects of confounding variables, and frank violations of the scientific method. These recent studies therefore do not invalidate the large body of previously published studies that established induced abortion as a risk factor for breast cancer.
Breast cancer incidence is increasing, as predicted from earlier studies. Disclosure of the probable contribution of induced abortion to the increase in risk should be part of the informed consent process for abortion.
According to a WND article discussing this study:
The basic biology underlying the ABC link boils down to the fact that breast cancer is linked to reproductive hormones, particularly estrogen. At conception, a woman’s estrogen levels increase hundreds of times above normal – 2,000 percent by the end of the first trimester. That hormone surge leads to the growth of “undifferentiated” cells in the breast as the body prepares to produce milk for the coming baby.
Undifferentiated cells are vulnerable to the effects of carcinogens, which can give rise to cancerous tumors later in life. In the final weeks of a full-term pregnancy, those cells are “terminally differentiated” through a still largely unknown process and are ready to produce milk. Differentiated cells are not as vulnerable to carcinogens.
However, should a pregnancy be terminated prior to cell differentiation, the woman is left with abnormally high numbers of undifferentiated cells, therefore increasing her risk of developing breast cancer.
Spontaneous abortions, or miscarriages, are not generally associated with increased risk, since they generally occur due to insufficient estrogen hormones to begin with.
Although this basic biological explanation remains undisputed, establishment cancer organizations and the medical community at large continue to deny or downplay the ABC link, using studies such as those criticized by Brind.
Abortion provider Planned Parenthood claims on its website that there is no ABC link, stating, “Attempts to prove [the cell differentiation] theory … have failed.”