The Pill and Breast Cancer

The oral contraceptive pill has been widely used since the late 1950s and early 1960s when it became a revolutionary tool allowing women to take control of their family planning for the first time. However, in the decades since, questions and concerns have been raised over its long-term safety. One concern is that taking the pill could increase your risk of developing breast cancer. 

The association between breast cancer and the oral contraceptive pill is small, but significant. Studies suggest that those women who are currently on the pill are 20% to 24% more likely to receive a breast cancer diagnosis. The increased risk is lost once the pill is discontinued and after ten years, prior pill users are at no greater risk than never users of getting breast cancer. The risk also falls significantly once a woman goes through the menopause.

Why would current pill use increase your breast cancer risk?

Pill use is associated with clinically challenging types of breast cancer, including the triple negative form, which usually has a worse prognosis and higher mortality rate. The exact mechanisms linking the two are unclear, although many breast cancers have a hormonal component. It is thought that increased lifetime exposure to oestrogens increases the risk of breast cancer, primarily because the hormone promotes or initiates tumour growth.

Studies have failed to find an elevated risk of breast cancer in pill users with a family history of the disease. However, the data may be skewed by the fact that these women are less likely to use the pill due to their already increased susceptibility.

The mini pill and breast cancer

The established link between oestrogen and breast cancer may lead you to wonder whether using the progestin-only ‘mini pill’ would be a safer option. There have been very few studies on this form of contraception, probably because it is not as widely used as the combined pill (which contains oestrogen and progestin). The work that has been performed has suggested that women who take the mini pill still have a higher risk of breast cancer than those who have never used oral contraceptives, perhaps by as much as 21%. The link between progestins and breast cancer is poorly understood and likely to be complex. However, it is validated by studies on postmenopausal women who take hormone replacement therapy. Those on combined oestrogen plus progestin therapy have a higher breast cancer risk than those who take just oestrogen. 

Thus, the mini pill is no longer considered a safer contraceptive option for those considered to be high risk for developing breast cancer.

Take home message

Women who are considered to be at higher risk of developing breast cancer, for example, those with a family history of the disease, will probably be encouraged to consider alternative forms of contraception. For many other women, the risks are low, becoming negligible once pill use is discontinued, and the benefits of the pill may well outweigh its negatives.

To read more about a possible link between pill use and cancer risk click here.

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Get in touch if you have any questions about this article or any aspect of women’s health. We’re here for you. 

Sources:

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• Gierisch, J. M., et al. “Oral Contraceptive Use and Risk of Breast, Cervical, Colorectal, and Endometrial Cancers: A Systematic Review.” Cancer Epidemiology Biomarkers & Prevention, vol. 22, no. 11, Nov. 2013, pp. 1931–1943., doi:10.1158/1055-9965.epi-13-0298.
• Knowlden, Hilary A. “The Pill and Cancer: a Review of the Literature. A Case of Swings and Roundabouts?” Journal of Advanced Nursing, vol. 15, no. 9, Sept. 1990, pp. 1016–1020., doi:10.1111/j.1365-2648.1990.tb01981.x.
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• “Oral Contraceptives (Birth Control Pills) and Cancer Risk.” National Cancer Institute, https://www.cancer.gov/about-cancer/causes-prevention/risk/hormones/oral-contraceptives-fact-sheet.
• Schairer, Catherine. “Menopausal Estrogen and Estrogen-Progestin Replacement Therapy and Breast Cancer Risk.” Jama, vol. 283, no. 4, 26 Jan. 2000, pp. 485–491., doi:10.1001/jama.283.4.485.
• Soroush, Ali, et al. “The Role of Oral Contraceptive Pills on Increased Risk of Breast Cancer in Iranian Populations: A Meta-Analysis.” Journal of Cancer Prevention, vol. 21, no. 4, 30 Dec. 2016, pp. 294–301., doi:10.15430/jcp.2016.21.4.294.