It was also true regardless of how old women were when the began taking the Pill, how long they took it and what type of Pill they took. The Imperial Cancer Research Fund in the United Kingdom underwrote the four-year study, which The Lancet published in June 1996. The complete paper constitutes a special supplement to the September 1996 issue of Contraception. The researchers did observe a very small rise in breast cancer among current and recent users of the Pill. It may be that doctors who prescribe the Pill feel more compelled to do more breast exams, or that the sort of women who ask for the Pill are more likely to ask for mammograms.
Cancer is a disease that develops over many years.
If the Pill actually caused cancer, you would see a delayed effect, not an immediate one. The finding that the cancers discovered in Pill users were less likely to have spread outside the breast than the cancers discovered in nonusers lends credence to Westhoff's hypothesis. For years researchers have been giving women mixed signals about the link between the Pill and breast cancer. Any one of those studies will get only a little piece of the answer. Thus, in 1992 more than 200 scientists from around the world joined to form the Collaborating Group on Hormonal Factors in Breast Cancer.