Pete Alsop will be 83 when he puts on his trainers for his first marathon attempt later this month. The 82-year-old, who had prostate cancer, is taking on the challenge in memory of his wife, Val, who died from bowel cancer.The octogenarian is a familiar sight pounding the pavements in St Neots, power walking three times a week. Residents in his retirement complex have pledged support, but Pete is paying the first £3,000 himself to say thank you to the charity. On April 28 he will tackle the Virgin Money London Marathon. And hes urging other runners, with a confirmed place, to raise money for Cancer Research UK too. Pete said: On my 80th birthday I decided I wanted to do something special and I walked 25 miles but the London Marathon will be my first full marathon. I really wanted to walk it for my Val and in memory of my mother and nan. But I also wanted to do it as a thank you to Cancer Research UK. Its something he could not have imagined doing more than 22 years ago, when he sat watching a news item on TV about prostate cancer. His wife suggested he went for a check. Pete said: I knew a normal prostate-specific antigen (PSA) level was anything below four, but my reading was six, so the doctor decided to keep a close eye on it. He received his cancer diagnosis later that year in 1997. Around that time, the couple moved to a retirement home in St Neots. Twelve years later, Val began to get stomach pains and was diagnosed with bowel cancer, which had spread to her liver. Despite deciding against surgery and chemotherapy, Val lived for a further two years. Pete said: Val died on March 18, 2008, and it still gets me to talk about it. Not many people were as fortunate as we were to have such a happy marriage; we were married for 47 years. He continued to get his PSA level checked. When the levels kept going up, Pete had injections into his stomach every three months for five years, followed by radiotherapy seven years ago. His reading went down to zero and he is now in remission. Pete then joined a local cancer support group Acorn and started fundraising by doing walks for charity. Pete said: Since then Ive done eight or nine sponsored walks of up to 10 miles but I started to add another 10 miles on top. I would like to help other people who have had cancer and share my view with them that you need a positive attitude, a determination to get fit and to decide you are going to get over it. I have known a lot of men who have had cancer and just decided to die, whereas my belief is that with all the research going on, you have a chance and you have got to take it. Danielle Glavin, Cancer Research UKs spokesperson for the East of England, said: We are so grateful to Pete for taking on this challenge for us at the age of 82. We wish him all the best with his training and also on the day of the marathon. Its thanks to the support of amazing people like Pete that were able to continue our research into kinder and more effective treatments for cancer. A great deal of progress has been made, but theres still so much work to do. Anyone who already has a place in the Virgin Money London Marathon can still join our team of runners. Or if a marathon is one step too far, why not try one of our other runs or sporting events instead and get involved to help support vital cancer research. To sign up to run for the charity, visit cruk.org\/marathon.