WHEN former Peebles rugby player Chris Noble noticed a bump on his toddler's head, he couldn't have imagined what lay ahead for his family.

This year, his son Alex should have been celebrating his fifth birthday and taking his first lessons at school.

But three years ago, at 20 months old, he was diagnosed with Neuroblastoma, a rare and aggressive childhood cancer.

Despite the bravest of battles he died in September, aged four - and now his dad Chris has resolved to run, hike, cycle and kayak 500km in a series of events to raise money for the Neuroblastoma Society and Maggie's Cancer Caring Centres.

Chris, who lives in Edinburgh with his wife Sarah and his other son Luke, aged three, said: "We first noticed something was wrong with Alex when he developed a bump on the head.

"We thought it was normal as he was a toddler and the initial check up didn't show anything wrong. But then he had an MRI scan that showed the bump was from inside his head.

"The scan revealed four tumours - it was one of those things that you don't really have a choice in how you cope, you just have to accept it and get on with it." Neuroblastoma is an especially brutal form of childhood cancer, as it is very difficult to treat and the chances of relapse are high.

Symptoms depend on where in the body the tumour is, but many are easily dismissed as normal childhood problems, making it difficult to spot. Fewer than 100 children in the UK are diagnosed each year, the majority being under five years old.

After he was diagnosed, Alex was taken to the Royal Hospital for Sick Children in Edinburgh and started chemotherapy and radiotherapy.

Chris added: "It was an extremely difficult time, but Alex went through each day with a great attitude.

"We were with him as much as we could, staying with him in hospital for months at a time.

"It was very tough as his younger brother Luke was only three months old at the time and he had to be looked after by grandparents. But all our friends and family were so supportive and rallied round." At first Alex seemed to be getting better and his family were able to make the most of their time together by taking the Lego fan on holidays, including to his favourite Legoland.

But, as often happens with neuroblastoma suffereres, he relapsed several times and before his parents knew it, was fighting for his life.

Chris and Sarah began raising money for treatment abroad - something that many parents are forced to do, as there is not enough research being carried out into Neuroblastoma in the UK.

Sadly they didn't make it that far, as Alex lost his battle with the cancer in September 2010.

Chris continued: "We are very conscious of the fact he would have been starting school this September. He was a bright little boy, always very inquisitive and full of energy, and he would have done well.

"He lived to the full and his life has inspired me to take part in a series of challeges, the last of which will finish the day before his fifth birthday." Chris has chosen the Maggie's Monster Bike and Hike on May 4 and 5 as one of his events. A team of five, including Chris Noble and family friend Karen Cornwall, from Peebles, aim to cycle 31 miles and hike 41 miles between Fort William and Inverness in 24 hours. Maggie's Centres provide support for people affected by cancer and have provided valuable support to Chris and his family.

In addition, there will be a fundraising quiz night in Peebles Rugby Club on Friday, April 26, at 7.30pm with raffle prizes and proceeds being donated to the Maggie's campaign. Teams of three to five people are invited to take part. For more information, or to donate, log on to their Just Giving page - www.justgiving.com/MaggiesforAlex