In what may spark a fierce debate, researchers claim that hormone replacement therapy doesn’t raise a woman’s risk of developing breast cancer.
A previous research, titled the Million Women Study, suggested that women taking hormone replacement therapy (HRT) were twice as likely to develop breast cancer and more likely to die from it than those not taking the therapy.
But, an international team, led by Samuel Shapiro from the University of Cape Town, now says the Million Women Study, carried out by Oxford University, is “fundamentally flawed”, the Daily Telegraph reported.
According to researchers, there were many flaws in the Million Women Study, including that women may have already had breast cancer when they were enrolled in the research, and that they were at increased risk of dying within three years which was “biologically implausible”.
“The name ‘Million Women Study’ implies an authority beyond criticism or refutation. Here we conclude that the evidence in the Million Women Study was indeed unreliable. There were defects in the study design, and the findings did not adequately satisfy the principles of causation.
“HRT may or may not increase the risk of breast cancer but the Million Women Study did not establish that it does,” Shapiro wrote in the Journal of Family Planning and Reproductive Health Care.