According to a recent article published in The Lancet, induced or spontaneous abortions do not increase the risk of a woman developing breast cancer.1
Since breast cancer is such a common malignancy in women in the United States, much time and money has been vested in trying to prevent the disease altogether. Researchers are continually evaluating the possible association between environmental and/or genetic factors and an increase or decrease in the risk of developing breast cancer, so that patients may modify their behavior to decrease their risk or undergo appropriate screening if they are at high risk. Debate has surrounded the issue of abortions, either induced (planned medical procedure) or spontaneous (unplanned miscarriage) and the risk of developing breast cancer. With induced abortion being a highly charged emotional and political debate, several studies have been performed to determine if women who undergo induced abortions are at an increased risk of developing breast cancer.
Researchers affiliated with the Collaborative Group on Hormonal Factors in Breast Cancer in England recently conducted a clinical study involving over 80,000 women to evaluate induced abortion and risks of developing breast cancer. All women in this study had been diagnosed with breast cancer, and data was obtained from 44,000 of these women prior to their breast cancer diagnosis. There was no difference in the risk of developing breast cancer whether a woman had one or more pregnancies ending in spontaneous or induced abortions, compared to those who had never had a spontaneous or induced abortion.
Other studies evaluating an association between abortions and breast cancer have also been conducted. In 1994, the Fred Hutchinson Cancer Research Center suggested that induced abortion may result in a 50% increase in the incidence of breast cancer.2 However, in 2000, another study by the Fred Hutchinson Cancer Research Center did not find any relation between induced abortions and breast cancer incidence.3 In 1998, researchers from the University of California reviewed data from all published studies involving abortions and breast cancer incidence, and found that there was either no effect between abortions and breast cancer incidence, or there appeared to be a decrease in incidence of breast cancer among women who had abortions.4 In yet another study published in the International Journal of Cancer in 2003, researchers from Sweden also found that breast cancer incidence was decreased in women who had at least one induced abortion.5
The researchers from England who conducted the most recent clinical study concluded that yet another study could not provide any evidence that induced or spontaneous abortions increase the risk of a woman developing breast cancer.
1.Collaborative Group on Hormone Factors in Breast Cancer. Breast Cancer and Abortion: Collaborative Reanalysis of Data from 53 Epidemiological Studies, Including 83,000 Women with Breast Cancer from 16 Countries. The Lancet . 2004;363:1007-16.
2.Daling J, Malone K, Voigt L, et al. Risk of breast cancer among young women: relationship to induced abortion. Journal of the National Cancer Institute. 1994;86:1569-1570.
3.Newcomb P and Mandelson M. A record based evaluation of induced abortion and breast cancer risk (United States). Cancer Causes Control. 2000;11:777-81.
4.Barthlomew L and Grimes D. The alleged association between induced abortion and risk of breast cancer: biology or bias? Obstet Gynecol Surv 1998;53:708-714.
5.Erlandsson G, Montgomery S, Cnattingius S. Abortions and breast cancer: record based case-control study. International Journal of Cancer. 2003;103:676-679.