Oct. 20, 2015 -- Women who undergo in vitro fertilization to have a baby are over a third more likely to get ovarian cancer than those who don't have the treatment, a new study suggests.
The actual risk of that happening is "very small," though, one expert says.
Scientists at University College London say the link may be partly driven by women who have endometriosis and other underlying health problems. But they say their findings "leave open the possibility" that IVF could be a risk factor for ovarian cancer.
A Common Cancer
The disease ranks fifth in U.S. cancer deaths among women, and it accounts for more deaths than any other female reproductive system cancer, according to the American Cancer Society. It’s estimated that more than 21,000 women will be diagnosed with ovarian cancer in 2015.
The team based their findings on 255,786 women who got IVF in England, Wales, and Scotland between 1991 and 2010. During a follow-up period of 8.8 years, there were 386 cases of ovarian cancer.
They also found that:
- Women who didn't have a baby after IVF were at greatest risk.
- The risk was not higher among women who'd gotten more than one cycle of the treatment.
- Women who were younger when they started IVF were at higher risk.
- Women who got the treatment because their male partner was infertile were not at an increased risk.
The findings, supported by grants from Cancer Research UK and the National Institute for Health Research, were presented at a meeting of the American Society for Reproductive Medicine in Baltimore.
"It’s important to remember that we are talking about a very small risk here. While the relative increase shown in this research is significant, the absolute risk of getting ovarian cancer remains low,” says Katherine Taylor, chief executive at the U.K.-based non-profit Ovarian Cancer Action.
She says the study "reiterates what we already know -- that ovarian cancer risk is marginally greater in women with a long menstrual history, i.e. those who don’t have children.”
"What this study doesn't tell us is whether the slight increase in risk is down to cause or effect. Further research is needed to determine whether it’s IVF treatment itself that increases risk, or whether it’s down to existing infertility issues."
These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.