Study: Fertility Drugs Do Not Increase Breast Cancer Risk

Treatments to stimulate the release of eggs increase estrogen hormone production and can act on breast cells, which has created concern that this could turn the cells cancerous.

Drugs routinely used to release eggs during fertility treatments do not increase women’s risk of developing breast cancer, according to new research from King’s College London.

Fertility treatments can range from the use of medications to boost the release of eggs during a woman’s natural fertility cycle to more complex treatments, such as in vitro fertilization (IVF), which involves stimulating a patient’s ovarian cycle, extracting eggs from their ovaries, fertilizing them in a laboratory, and then transferring the embryo into the womb.

Drugs to stimulate the release of eggs have been used to treat infertility since the early 1960s, according to the study. These treatments increase estrogen hormone production and can act on breast cells, which has created concern that this could turn the cells cancerous.

“Fertility treatment can be an emotional experience,” said author Yusuf Beebeejaun, MRCOG, MHDL, MBBS, in a press release. “Patients often ask us if taking ovarian stimulating drugs will put them at increased risk of developing cancers, including breast cancer. To answer that important clinical question, we undertook this review that reports data from nearly 2 million people.”

A team of investigators analyzed studies with 1.8 million women undergoing fertility treatments, who were followed for an average period of 27 years and had no increased risk of developing breast cancer. According to the press release, it is the largest study to date assessing whether commonly used fertility drugs increase cancer risks.

“Our study showed that the use of drugs to stimulate ovaries in fertility treatment did not put women at increased risk of breast cancer,” said senior author Sesh Sunkara, MD, in the press release. “This study provides the evidence needed to reassure women and couples seeking fertility treatments.”

Women of all reproductive ages were included in this study. The investigators found no significant increase in risks among women exposed to treatment compared to untreated women, and untreated women who were infertile.

“So much of the fear, stress, and anxiety associated with fertility treatment is rooted in navigating uncertainty,” said patient advocate Katy Lindemann in the press release. “This study not only gives patients peace of mine at an emotional level, but also enables us to make more informed decisions about treatment risks and benefits at a rational level.”

REFERENCE

Fertility drugs do not increase breast cancer risk, study finds. News release. King’s College London. June 21, 2021. Accessed June 22, 2021. https://www.kcl.ac.uk/news/fertility-drugs-do-not-increase-breast-cancer-risk-study-finds