Testicular transplants yet to produce sperm

The men have so far failed to produce sperm

Revolutionary operations aimed at restoring fertility in men after cancer therapy have been unsuccessful so far, say doctors.

None of the men involved have managed to produce new sperm, although experts said they believed that more time might be the answer in some cases.

The pioneering work is being carried out at the Christie Hospital in Manchester by a team including Dr John Radford and Professor Roger Gosden.

We will be trying to find out why it isn't working

Dr John Radford

It is the first time that a team has tried to help a sterile man with a transplant of his own preserved testicular tissue.

So far, seven men - who had their own testicular tissue frozen prior to chemotherapy - have had cells reimplanted.

The hope is that the cells would reproduce and gradually restore sperm-producing ability to the seminferous tubules of the testicle.

Doctors have already been able to make this happen in mice experiments.

No signs of sperm

However, although the first of these operations took place two years ago, so far none of the men have shown any signs of sperm production.

The team is now preparing to re-examine their methods to look for alternative approaches.

Dr Radford told BBC News Online: "We will be trying to find out why it isn't working.

"We are not sure we have waited long enough yet."

The only obvious difference between the methods used on mice and humans was that while entire "tubules" could be implanted into mice, in humans they have to be broken down and injected in a liquid suspension of single cells.

One potential solution, said Dr Radford, would be to implant entire human tubules under the skin, from where sperm could be retrieved later for use in fertility treatment.

Currently men about to embark on sterilising cancer treatment are offered the chance to store semen for use later in standard fertility techniques.

However, this presents problems, particularly for younger boys, who cannot produce a viable sample.

There have been concerns that reimplanting tissue taken from a cancer patient prior to treatment could read to the reimplantation of cancer cells, and the return of the disease.

Dr Radford acknowledged that this was a major concern, but said that in this case, the only patients involved were Hodgkin's Lymphoma patients.

It was, he said: "practically unheard of" for cancerous cells to be present in the testicles of these patients.