Coming Home

A much-ignored story in science and medicine is the emerging body of data that suggests a link between abortion, contraception and breast cancer. It would seem that the ‘authorities’ have spoken and the matter is finished in their eyes. The American Cancer Society (ACS) and the National Cancer Institute have both published fact sheets to close the conversation on a growing body of literature to the contrary. This will be a recurring issue on this blog.

While future posts will treat the topic systematically, a solid beginning needs to be a critique of the critics.

At issue is the validity of two methodological approaches to the topic: Retrospective Studies and Prospective Studies.

Retrospective studies begin with women who have breast cancer and a similarly aged control group. Looking back, in retrospect, the women report their entire health history, including the use of oral contraceptives and having had abortion(s). A number of retrospective studies, linked above, have demonstrated an increased incidence of breast cancer in women who have had abortions. ACS claims that this is nothing more than, “Recall Bias”. That is to say, according to ACS:

“Studies have shown that healthy women are less likely to report that they have had induced abortions. In contrast, women with breast cancer are more likely to accurately report their reproductive histories. This may be because they are looking for anything that may be linked to the cancer.”

While this may be true in some other studies, it strains credulity to suggest that when asked directly women would somehow fail to recall an abortion. Presumably these studies employed what is known as social desirability scales to screen for respondents who might not be truthful in responding to such queries. Also, if healthy women fail to report induced abortions, how would the researchers know? If in those studies the researchers became aware of the past abortions in healthy women, why not in the retrospective studies dealing with breast cancer and abortion?

Prospective Studies are those that start with a group and follow them going forward. The great strength of a prospective study is that it eliminates recall bias. Two large prospective studies have been cited as indicating no link with abortion. However, as Joel Brind, Ph.D. properly points out in a critique published in Journal of American Physicians and Surgeons, these studies did not follow the women long enough. One study concluded after only ten years. It usually takes cancer a minimum of fifteen years to develop. Brind’s critique of the methodological flaws in the NCI and ACS fact sheet conclusions is spot on.

With the methodological flaws of the prospective studies clearly exposed, this topic deserves much greater scrutiny.