Research Profile - Fertility? But I’m just a boy!

Sometimes, you need to make decisions at a very early age – decisions that will have a huge impact on your future life.

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And a long life it will likely turn out to be, even for boys who survive cancer as young children. Advances in treatment have ensured that more and more of these boys will survive. Unfortunately, those same treatments often leave survivors infertile. And that poses particular problems for boys.

It's different for adult men – sperm banking means that they can freeze their sperm before treatment and thaw it when they're ready to become parents. But sperm don't appear until after puberty. What kind of options do prepubescent with cancer have?

Dr. Peter Chan wants to ensure that these children – or, more realistically, these children and their parents – have a choice. He and Dr. Makoto Nagano are working with sperm stem cells – the cells that are present in the body at birth but will only become sperm with the arrival of puberty – to see if they can be collected before cancer treatment, frozen and stored, and then released to become sperm when a man decides to become a father.

"We've been thinking about this problem for a long time," says Dr. Chan, the Director of Male Reproductive Medicine at McGill University.

Dr. Chan's earlier research showed the impact chemotherapy can have on fertility. His work was instrumental in the development of guidelines mandating sperm banking for men undergoing cancer treatment. Sperm banking is now, in fact, the international standard. But, he says, once the banked sperm runs out, the men are effectively infertile.

That's what makes this research so promising, he says. It actually goes a step beyond fertility preservation through sperm banking to fertility restoration. This can happen in two ways – after cancer treatment the sperm stem cells can be implanted back in the testes, where they mature and provide an ongoing supply of sperm, just as they do in men who haven't undergone cancer therapy. Or they can be matured in the laboratory and used with assisted reproductive technologies. That makes Dr. Chan's research important not only for children, but for all males undergoing cancer treatment.

This is still very basic research, he cautions, and there's a lot of work on sperm biology that has to be done before any application is possible. He has to learn, for instance: whether: sperm stem cells can be harvested; if they can survive outside the body for an extended period of time; and, if they can mature into sperm.

If all the answers to these questions are positive, Chan still needs to determine whether sperm stem cells can be transplanted back into the source.

Still, he is confident that his can be the first team to make this possibility come true. Dr. Chan is so optimistic, he's working with childhood cancer survivors and their families, as well as the health-care professionals who treated them, to find out what they would have liked in the way of fertility counselling and what kinds of interventions to preserve fertility they would accept. In addition to developing the technology, Chan also wants to develop guidelines to ensure health-care providers offer proper fertility counselling to young boys with cancer and their parents.

"Our priority is the technology. If that doesn't work, then nothing else matters," he says. "But when you deal with this kind of sensitive subject, we have to make sure it's something people will accept. Otherwise it would just be voodoo science."

"There's a lot of projects where the link to the real world is missing."

The study

Dr. Peter Chan is undertaking a two-pronged project that marries basic science with optimizing service delivery. On the basic science side, he is investigating the biology of spermatogonial cells, or sperm stem cells, to find out how they can be harvested, stored, and convinced to mature into sperm, as well as whether they can be transplanted back into their original source. On the service delivery side, he is working with health-care professionals, childhood cancer survivors and their parents to find out what kinds of information they would like to have in order to facilitate their decisions and whether harvesting sperm stem cells would be acceptable. With these two quite different aspects to the research, Dr. Chan has assembled a team of experts, including scientists, clinicians, psychologists, pediatricians and cancer specialists, who are world-renowned in their individual fields. The challenge, he says, is to get them talking to each other.