The largest and most comprehensive study on IVF treatments ever recorded has made it official: There is no link between in vitro fertilization and the potential risk for breast cancer.
That's extremely good news for the 7.4 million American women, or 11.9% of the female population, who have received infertility treatments in their lifetimes, but it's also good for the future of IVF itself.
This new research from the Netherlands debunks previous, smaller studies that suggested a possible link between IVF treatments and the risk of developing breast cancer later in life. None of the previous studies could point to a central consensus. Some said the effect was more pronounced in younger women, who are most fertile between the ages of 20 and 24, while other studies said cancer risk was greater for women who underwent the IVF process later in life, when fertility starts to decline after age 30 and even more so after age 35.
"The main takeaway is there's no evidence of an increased subsequent risk of breast cancer, at least in the first couple decades," Dr. Saundra S. Buys, an oncologist at the Huntsman Cancer Institute at the University of Utah, told The New York Times.
Though the research did not include any post-menopausal women, it did follow some 25,000 Dutch women who had received IVF treatments for a median period of 12 years. They were not found to have any significant increased risk for developing breast cancer over any of their peers.
Additionally, the study also found that breast cancer risk was even lower for women who had undergone seven or more IVF cycles compared to those who only received one or two IVF cycles. This suggests that the elevated levels of estrogen and progesterone, which were at first thought to be the catalyst for any supposed breast cancer link, cannot be the culprit, since women with multiple IVF cycles would have had much higher hormone levels.
While the evidence is not conclusive, it does point to a greater understanding and reassurance for all women. The study, published in the Journal of the American Medical Association earlier this month, said that their "findings are consistent with absence of a significant increase in long-term risk of breast cancer among IVF-treated women."