IVF treatment may double the risk of ovarian cancer

IVF may double a woman's risk of ovarian cancer later in life, according to new research.

Overall, women given fertility drugs to stimulate the ovaries into producing eggs were twice as likely to develop ovarian cancer and borderline ovarian tumours compared to women who were not treated with IVF, researchers from The Netherlands Cancer Institute found.

Professor Flora van Leeuwen, an epidemiologist who led the study, said: "This study, with 15 years of follow-up, is the first to include a comparison group of subfertile women not treated with IVF.

"This is particularly important because IVF-treated women are different from the general population due to the fact that difficulty conceiving or never having been pregnant are known risk factors for an increased risk of developing ovarian malignancies."

The researchers reached their conclusion after analysing data on more than 19,146 subfertile women attending IVF clinics who received at least one IVF ovarian stimulation treatment and 6,006 subfertile women who did not undergo IVF.

A total of 77 women developed malignancies, 66 of whom had undergone IVF treatment. Of these, 30 had invasive ovarian cancer and 31 had borderline ovarian cancer.

This proportion of ovarian borderline tumours was unusually high, the researchers said.

Although borderline ovarian tumours are usually not fatal, they can turn into cancer, and require extensive surgery.

After taking into account other factors which may influence the results, such as age, how many children (if any) the women had, and cause of subfertility, the researchers estimated that women in the IVF treatment group had double the risk of ovarian cancer, and four times the risk of borderline ovarian cancer compared with subfertile women who had never undergone IVF treatment.

Prof van Leeuwen said: "Our data clearly show that ovarian stimulation for IVF is associated with an increased risk of borderline ovarian tumours and this risk remains elevated up to more than 15 year after the first cycle of treatment."

"The individual risk of developing ovarian cancer or a borderline ovarian tumour is very low. In The Netherlands the cumulative risk of ovarian malignancies (including borderline ovarian tumours) before the age of 55 is 0.45% in the general population.

"The results of our analysis suggest this risk increases to about 0.71% for women who undergo IVF, with the increase being due to borderline tumours of the ovary.

"More research is needed to examine the risk of invasive ovarian cancer, especially after a longer follow-up in IVF treated women."

The study is published online in the journal Human Reproduction.

This article was published on Thu 27 October 2011