孩子的腫瘤發生率也增加了， 研究貼在這裏

IVF link with cancer discovered

A second study in the space of a week today suggested a link between in-vitro fertilisation and cancer.

Researchers in the Netherlands found indications of an up to seven times increased risk of eye cancer among children conceived by IVF.

The scientists themselves cautioned that the findings were preliminary and it was too early to reach definite conclusions.

But their publication in the Lancet medical journal comes just a week after British researchers disclosed a link between assisted fertilisation and a rare genetic defect that can lead to kidney cancer.

Retinoblastoma, a malignant tumour in the retina, occurs in only about one in 17,000 births in western countries.

However Dutch investigators led by Dr Annette Moll, from VU University Medical Centre in Amsterdam, diagnosed the disease in five IVF children born within 15 months of each other.

This prompted the team to compare these cases with the expected incidence of retinoblastoma in the normal population.

The researchers estimated that children conceived by IVF could be between five and seven times more likely than non-IVF children to develop retinoblastoma.

Between 1% and 1.5% of Dutch babies are born through IVF, which is used to treat 3,000 women each year.

Dr Moll said: "Whether treatment with ovulation-inducing drugs increases the risk of childhood cancer is an important matter, especially with the rising numbers of women undergoing treatment for subfertility.

"Future investigators should consider the number of IVF treatments, other fertility drugs given before IVF, and the possibility that serious disorders in children conceived by IVF are diagnosed earlier than those in other children who do not have such close medical surveillance.

"Our finding requires further research to confirm the association and to explore a possible causal mechanism."

In an accompanying commentary in the Lancet, Professor David BenEzra from Hadassah Hebrew University Hospital, Jerusalem, also stressed the need for caution.

He said: "Whatever the 'true' incidence of retinoblastoma is after IVF, there is little doubt that a heightened awareness and a multidisciplinary approach with a closer follow-up of children conceived with assisted reproductive technologies is needed.

"An open debate on this issue is necessary to frame it in its proper context and to minimise potential harmful effects of unfounded and potentially misleading information."

The British Fertility Society, which represents

IVF professionals, said it would continue to

review new research on the safety of fertility treatment.

It pointed out that the chance of any child, whether conceived naturally or through IVF, developing cancer before the age of 15 was one in 600. About 80% of these cases were curable.

There was no evidence that the overall risk of cancer was increased after assisted conception treatment.

Dr Alison Murdoch, chairman of the BFS, said: "The number of children born after IVF will continue to increase as the treatment and its availability improves. Sadly, it is inevitable that some of these children will develop the same problems suffered by other children who were conceived naturally.

"Whilst it is vital that we are aware of the potential risks of IVF, patients who have children as a result of IVF can be reassured that this report is an isolated finding. Parents should remain confident that their children need no tests for this condition."

Last week researchers from Birmingham and Cambridge revealed that children with Beckwith-Wiedemann syndrome were four times more likely than the general population to have been born after assisted fertilisation.

The genetic disorder which normally affects two to five children in every 100,000, causes a pattern of symptoms including overgrowth and an increased risk of kidney cancer.