THE search for a bone marrow match for Emily Clark, the Gwent teenager currently fighting a second battle against the cancer non Hodgkin lymphoma, has during the past week seen hundreds of people sign up to become potential donors. ANDY RUTHERFORD looks at what the process entails, and how it can provide a vital lifeline for patients.

“A STRANGER, a hero...” These are 17-year-old Emily Clark’s own words, not only for the person who might provide her with the bone marrow match she requires in her own cancer battle, but for everyone who comes forward as a potential donor.

The call has gone out during the past eight days – through the Argus, social media and this brave Cwmbran teenager’s own campaigning website – for people to join bone marrow donor registries to give her and thousands like her the best chance of recovery.

Emily was diagnosed last December with non-Hodgkin lymphoma (Burkitt’s), one of around 60 different types of this particular cancer and one which grows quite quickly.

Robust treatment, including surgery on Christmas Day to fit a chest drain and four courses of chemotherapy followed, and by mid-April she was declared free of cancer.

A couple of weeks ago however, she was told the cancer had returned, and that a bone marrow transplant now offers the best chance of survival.

Unfortunately, Emily’s sister Holly has subsequently been found not to be a match, though there was only a 25 per cent chance of such a sibling match-up happening – and so the search widens.

People who wish to sign up as potential stem cell or bone marrow donors – both provide the vital ingredients for a transplant – can do so through a number of routes.

In Wales, the Welsh Blood Service runs the Welsh Bone Marrow Donor Registry, while the Anthony Nolan charity runs its own registry, and since early in 2013 another charity – Delete Blood Cancer UK – has run a registry.

You can join the Welsh registry from the age of 17 through to your 31st birthday, though you remain on the register until you are 45. The Anthony Nolan registry age range is 16-30 years.

The evidence suggests that bone marrow from younger donors has a better chance of success and Anthony Nolan registrant Victoria Rathmill – the sort of ‘hero’ needed by Emily Clark – last year became the world’s youngest stem cell donor, at 17.

But Delete Blood Cancer UK’s age range is 17-55 years, reflecting its aim to widen the potential donor ‘pool’, and there is also the British Bone Marrow Registry, run by NHS Blood and Transplant, which holds details of potential donors from England, Scotland, Northern Ireland and North Wales, and which has an age range of 18-49 for joining up.

Helping maximise the opportunities of a match for patients who require a bone marrow transplant are systems of links between bone marrow registries the world over, which can potentially match up a donor with a patient on the other side of the globe.

Such links are vital given that, according to Anthony Nolan, around 2,000 people in the UK alone find themselves in need of a bone marrow transplant every year, and for most it is usually their last chance of survival.

l For many people signing up to bone marrow registries, the call informing them that they are a potential match will never come, but for others that call can come within weeks.

This phenomenon mirrors that of those waiting for a match and a potentially lifesaving donation.

Anthony Nolan estimates that once you are on its register you have a one-in-1,200 chance of being asked to donate, but your chance of being chosen to donate depends to a considerable extent on your age and gender.

Dr Stephen Field, medical director with the Welsh Blood Service, said that while bone marrow from a younger donor has a better chance of proving successful, “that does not preclude older donors if they are already on the register.”

Once a donor is selected, he said, the process of preparing for and carrying out a donation can move quickly.

“As soon as we contact them and a medical history questionnaire is completed, providing that is OK we can get them in for counselling,” he said.

There are two ways of donating – providing bone marrow directly through an injection into bone in the pelvic area, carried out under general anaesthetic or, nowadays the most popular, providing stem cells from blood through a process called apheresis, where your blood is passed from one arm and through a machine that harvests stem cells, then put back in through your other arm.

The latter procedure is preceded by a short course of a drug called GCSF, which boosts the number of stem cells in your bloodstream.

“The old fashioned way is the bone marrow donation, but nowadays most donors (around 90 per cent) go with the stem cell option through the machine, which is also the preferred option for the transplant centres,” said Dr Field.

“But that depends on the donor and other factors, such as if they have ‘good’ veins.

“Prior to that, following their counselling, they will then go to an independent medical examiner. As a registry we are advocates for the donor, so we need an independent view of their fitness.

“When that comes back, I or one of my colleagues will sign it off if everything is OK and then we arrange for the donation.”

For Welsh Blood Service donors the procedure is carried out at St Joseph’s Hospital in Newport, which provides a quieter backdrop.

“We have around 60 people a year from Wales who donate. A large proportion of those donations go to people requiring transplants in Europe and the USA, but they can go all over the world,” said Dr Field.

l Stem cell and bone marrow transplants are a way of enabling doctors treating cancer patients – primarily those with blood and lymph cancers – to administer very high doses of chemotherapy.

Such high doses can kill off the cancer cells, but also destroy the stem cells that make blood cells in the bone marrow, meaning they need to be replaced.

Stem cells in bone marrow produce three important types of blood cells – red blood cells, which carry oxygen around the body; white blood cells, vital in helping fight infection; and platelets, which help stop bleeding.

As well as blood and lymph cancers such as leukaemia and lymphoma, bone marrow and stem cell transplants are used to treat bone marrow failure, known as severe aplastic anaemia, and other blood and immune system disorders.

When a stem cell or bone marrow match has been found, whichever is being used is fed back into the patient’s body through a central line, a catheter through which chemotherapy and other medicines are administered.

These then find their way into the patient’s bone marrow, start to grow, and then begin to produce new blood cells.

Through this whole treatment, the patient becomes especially susceptible to infection that the body may not be able to fight.

A period of extended isolation will thus be necessary until the body’s immune system strengthens.

l For more information:

l Emily Clark is campaigning for people to sign up as bone marrow and stem cell donors. Details of how to sign up, the campaign, her story, her activities, and those of her supporters, can be found at remissionpossible.org.uk

l The following websites contain a range of information and downloadable leaflets on bone marrow and stem cell donation, and also how to sign up:

welsh-blood.org.uk

anthonynolan.org

deletebloodcancer.org.uk

nhs.uk/conditions/Bone-marrow-donation

l The charity Cancer Research UK provides valuable and detailed information about bone marrow and stem cell transplants and the vital role they play in the fight against a range of cancers, including non-Hodgkins lymphoma. Visit cancerresearchuk.org