London - IVF patients are a third more likely to develop ovarian cancer, a landmark UK study suggests.
Doctors say the extra risk shows the need for women to be screened for the disease following fertility treatment.
Scientists analysed the records of all the 255 000 Britons who have had IVF over the past two decades. Initial results show those who have had help to conceive are 37 percent more likely than other women to develop ovarian cancer.
The study’s authors say the most probable explanation is that the underlying problems making women infertile also put them at greater risk of cancer. But they admit there is a small possibility that the treatment itself is to blame.
Women were in most danger from ovarian cancer in the three years after starting IVF.
This, along with the fact that the risk was greater among younger women, supports the theory that the treatment itself is linked to disease. Previous research has suggested that IVF drugs may promote cancer growth. This suggests the danger comes from stimulating the ovaries to produce multiple eggs instead of just one. Even if this were true though the chance of getting cancer is still very low.
Alastair Sutcliffe, the professor in charge of the University College London study, said he was convinced IVF itself was not at fault.
“This internationally-unique study suggests little for women to worry about regarding the risk of cancers and the drug treatments they undergo to have a baby with IVF,” he said.
But Dr Stuart Lavery of Imperial College London said the study suggests that for women already prone to cancer because of their infertility, IVF treatment may increase that risk.
“Patients are very interested in the long-term impact fertility treatment has,” he added. “Every single woman who comes through our doors wants to know what the long-term consequences will be.”
Professor Geeta Nargund, medical director of Create Fertility, which has five UK clinics, said the findings called for caution. “This is a very important study,” she said. “Not enough has been done to safeguard the health and safety of women undergoing IVF in the UK.
“The causative factors at the moment are not clear – but until they are we should support cancer screening on the NHS. And we have an obligation to give women robust information that allows them to make informed decisions.”
Adam Balen, who chairs the British Fertility Society, also suggested routine cancer screening for IVF patients. “We need to call for a policy on this,” the professor said.
And Richard Kennedy, a gynaecologist in Coventry and president-elect of the International Federation of Fertility Societies, said the “broadly reassuring” data drew attention to the need for continued monitoring of treatments.
The take-up of IVF has hugely increased as more Britons put off starting a family until it is too late to conceive naturally. Around 50 000 have the procedure each year.
The UCL study looked only at the statistical chance of developing ovarian cancer – and did not examine the possible reasons behind this. Only 15 women out of every 10 000 who had IVF developed the disease during the research period.
The rate among all other women was little different: 11 in 10 000. The researchers found no increased risk of breast or womb cancer.
Professor Nargund said IVF should be used only when it was really needed, adding: “We must, where possible, help couples conceive as naturally as possible. What we do not want is our interventions to put women’s health at risk.”
Dr Julie Sharp, of Cancer Research UK, which funded the study, said: “The causes of ovarian cancer are complex and we’re funding this type of research to give us a better understanding of the most important risk factors, so that we can better advise women thinking about fertility treatment.”
Katherine Taylor, of Ovarian Cancer Action, said the relative increase in risk was significant although the absolute risk of getting ovarian cancer remained low.
Results from the study – the largest ever investigation of possible links between IVF and cancer – will be released at the American Society for Reproductive Medicine’s conference.
Daily Mail