IVF does not increase long-term risk of ovarian cancer

Women who have received fertility treatment are not at increased risk of ovarian cancer, according to a new study. 

A team of researchers from multiple institutes in the Netherlands investigated a group of around 40,000 women with fertility problems, of which around 30,000 had at least one IVF cycle between 1983-2000. They found that among this group of 'subfertile' women, those who had received fertility treatment were not at increased risk of ovarian cancer compared to those who had not. 

'Even after three or more IVF treatments and in the long term (twenty years), the risk of ovarian cancer was not increased,' said Dr Mandy Spaan, postdoctoral fellow at the Netherlands Cancer Institute and the Academic Medical Center, Amsterdam, the Netherlands and first author of the study. 

Previous research into the association between receiving fertility treatment and ovarian cancer has led to inconsistent results. The women in the study – a nationwide cohort from the Netherlands – were (retrospectively) followed for a median of 24 years, over which time 158 invasive ovarian cancers developed. The incidence of invasive ovarian cancer was not increased in the women who had received fertility treatment versus those who had not, although the incidence of borderline ovarian tumours was increased. In contrast to invasive ovarian cancer, borderline ovarian tumours are not generally malignant and have a good prognosis. 

However, the study published in the Journal of the National Cancer Institute found that women who received fertility treatments did have a higher risk of invasive ovarian cancer than women in the general population. The authors attribute this to the high proportion of subfertile women who remain childless (whether or not they receive fertility treatment), claiming that childlessness is a known risk factor for ovarian cancer. Supporting this, women who had more successful IVF cycles had a reduced risk of invasive ovarian cancer. 

A limitation of the study is that ovarian cancer is very rare in women under 50 years of age, with the overall number of cancers detected very small. The lead author, Professor Flora van Leeuwen from the Netherlands Cancer Institute, said 'It is important to realise that even with the long follow-up in our study, the median age of the women at end of follow-up was only 56 years. As the incidence of ovarian cancer in the population increases at older ages, it is important to follow assisted reproductive technology-treated women even longer.'