When 29-year-old Callum Stroud from Kent crossed the finish line at the Royal Parks Half Marathon this year, he wasn’t just completing a race — he was defying the odds. Diagnosed with Acute Lymphoblastic Leukaemia (ALL) in his mid-20s and told at one point that he might have only days to live, Stroud’s journey from a hospital bed to running 13.1 miles through London’s royal parks is a remarkable story of courage, resilience, and hope.
His determination to live fully, even while undergoing active cancer treatment, stands as a powerful reminder that strength is not defined by circumstance, but by choice. Stroud’s diagnosis came as a devastating shock in 2022, when he was just 26 years old and looking ahead to what should have been the prime of his life. The months that followed were marked by intensive treatment, painful relapses, and an emotional battle to hold onto a sense of normalcy.
Yet, despite the setbacks and uncertainty, he has chosen to push forward — not only surviving but actively challenging himself to achieve what few in his condition ever have. Completing the Royal Parks Half Marathon in two hours, eight minutes, and 48 seconds was more than a personal victory; it was a message to others facing hardship that perseverance can redefine what is possible.
A Life Changed Overnight: The Diagnosis That Shattered Normalcy
Before his diagnosis, Callum Stroud was living a busy, active life. Working as an engineer, he was physically fit, energetic, and, like most people in their twenties, planning for the future — not hospitals, treatment schedules, or life-threatening illnesses. But in early 2022, after feeling unwell for several weeks, Stroud decided to see a doctor. What he expected to be something minor turned out to be a battle for survival. He was diagnosed with Acute Lymphoblastic Leukaemia, a rare and aggressive form of blood cancer that progresses rapidly without immediate treatment.
“The news that you might not be here in a matter of days was terrifying,” Stroud recalled. “It’s a moment that still haunts me.” Within hours of his diagnosis, he was rushed to University College Hospital London, where doctors warned him that without swift intervention, his condition could become fatal within three days. There was no time to process or prepare; the fight began immediately.
The next few months were consumed by intense chemotherapy and immunotherapy sessions. The treatment was both physically and emotionally exhausting, leaving him weak and uncertain about the future. Yet, amid the chaos, Stroud held onto a sense of purpose. He spoke later about the shock of experiencing such a life-altering illness at a time when most of his peers were building careers, travelling, or starting families. “Everything you thought you knew about your future just disappears,” he said. “You have to rebuild from the ground up — and that’s not easy when you’re also fighting to stay alive.”
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His treatment journey has been relentless. After months of chemotherapy, he experienced not one but two relapses in 2023, each one forcing him back into the hospital and into more rounds of grueling therapy. But instead of breaking him, these challenges hardened his resolve. In March 2024, he was approved for CAR-T cell therapy — a cutting-edge treatment in which doctors reprogram a patient’s own T-cells to target and destroy cancer cells. The therapy offered new hope, though it came with its own risks and intense side effects.
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For Stroud, however, the procedure represented more than a medical milestone. It was proof that he still had reasons to keep fighting — that his story was not over yet.
Running Through Treatment: Finding Strength in Movement
Running while undergoing chemotherapy would seem unimaginable to most, but for Callum Stroud, it became both a physical outlet and a mental lifeline. His decision to sign up for the Royal Parks Half Marathon came earlier this year, after spotting an advert for the race on the London Underground. Something about it spoke to him — perhaps the symbolism of running through the city that had been both the backdrop of his treatment and his recovery.
Training for a half marathon while receiving chemotherapy and spinal injections every six weeks was far from simple. Stroud is currently on a maintenance programme that includes chemotherapy tablets, intravenous infusions, and injections directly into his spinal fluid — a regimen expected to continue for another two years. Yet, despite the fatigue and the unpredictable side effects of treatment, he found solace in the structure that running provided.
“Training was challenging,” he admitted, “but I found it gave me a lot of benefits mentally and physically to deal with my situation.” His commitment to the sport was also inspired by his younger brother, who had run the London Marathon while Callum was receiving CAR-T therapy. Watching that act of solidarity and strength stirred something deep within him. “It made me think, if he can do that for me, then maybe I can do something for myself too,” he said.
Stroud’s consultant, amazed by his determination, reportedly told him he had never seen anyone in such an advanced stage of treatment attempt something so demanding. Friends, family, and colleagues often called him “crazy” for taking on the challenge — a reaction he met with humour and quiet resolve. “In my crazy mind, that only made me want to achieve this goal even more,” he said.
The race itself was a triumph of endurance and emotion. As thousands of runners filled the streets of London, weaving through Hyde Park, Green Park, St James’s Park, and Kensington Gardens, Stroud joined them not just as a competitor but as a symbol of what the human body and spirit can overcome. Supported by Macmillan Cancer Support — an organisation that has been by his side since the beginning of his diagnosis — he crossed the finish line after two hours, eight minutes, and 48 seconds.
For someone who once faced the possibility of having just days left to live, every step of that race was a declaration of life. “A lot of people told me I shouldn’t do it,” Stroud reflected, “but running has helped me feel alive again. It’s given me control in a situation where you often feel powerless.”
A Message of Hope: Redefining What It Means to Keep Fighting
Beyond the physical feat of running a half marathon, what makes Callum Stroud’s story truly extraordinary is the message it carries — a message of hope, resilience, and perspective. His journey embodies the idea that even in the darkest circumstances, there can be light, and that purpose can be found in the very act of persevering.
Cancer, especially in young adults, can be profoundly isolating. It disrupts careers, relationships, and a sense of identity. For Stroud, the disease forced him to leave his engineering job — a role he loved but could no longer sustain physically. Instead of giving up, he chose to adapt, retraining in marketing and joining Publicis Groupe, a company known for its “Working with Cancer” policy that supports employees battling serious illnesses. The shift not only gave him a new professional path but also a sense of belonging and stability during uncertain times.
“All of those plans you make in your twenties go out of the window,” he said. “Somehow, you have to find a way to navigate everything — your health, your finances, your future — while still trying to live.”
Through his connection with Macmillan Cancer Support, Stroud found community and assistance that helped him manage both the emotional and practical challenges of his diagnosis. The charity has provided not just medical guidance but ongoing encouragement, helping him maintain the mental strength required to keep pushing forward. In turn, his decision to publicly share his story and run the Royal Parks Half Marathon was his way of giving back — of inspiring others facing illness to believe that their lives are not defined by their diagnosis.
His run has since resonated widely, drawing attention to the importance of mental health during cancer treatment and the incredible resilience patients display every day behind hospital walls. By choosing to run — not after his recovery, but during his treatment — Stroud has challenged the conventional narrative of what it means to be “sick.” He has shown that healing isn’t always about waiting for better days but creating them, one determined step at a time.
As he continues his maintenance therapy, which will extend for another two years, Stroud remains pragmatic yet optimistic. He acknowledges the difficulties — the fatigue, the uncertainty, the lingering trauma of nearly dying — but he refuses to let them define his outlook. His focus now is on living meaningfully, cherishing the everyday moments, and continuing to advocate for others who may feel hopeless or trapped in their diagnosis.
“Running that race wasn’t about proving I was healthy,” he said. “It was about proving that I’m still here — still fighting, still living. And if my story can help even one person keep going, then it’s all been worth it.”
The Royal Parks Half Marathon may be just one chapter in Callum Stroud’s ongoing journey, but it captures the essence of who he is: a fighter who refuses to be limited by circumstance. From a hospital bed to a finish line in the heart of London, his story is a powerful testament to human resilience — a reminder that courage is not the absence of fear or pain, but the decision to move forward anyway.
Through every mile he ran, every treatment he endured, and every setback he faced, Callum Stroud has become a symbol of unwavering determination. His journey continues, but for now, the image of him crossing that finish line — weary but triumphant — stands as a beacon of hope for anyone facing their own uphill battle.