I thought my bloating was IBS…but it was actually a giant tumour the size of a newborn baby

A super fit Birmingham woman who collapsed moments after finishing a triathlon was shocked to discover a deadly tumour had been growing in her abdomen for months — and had reached a whopping 11 lbs — larger than the average newborn.

Samantha Boswell, 53, had suffered mild back pain and bloating before her sudden collapse, but assumed the symptoms were due to her extreme exercise routine and irritable bowel syndrome. 

However, she did not seek help and the illness came to a head minutes after completing the astonishing physical challenge in August 2022. 

She was rushed to hospital where doctors discovered a massive soft tissue tumour in the back of her abdomen, close to the kidneys, known medically as a retroperitoneal sarcoma.

After life-saving surgeries, including the removal of part of her bowel, it took the mother-of-one over a year before she could walk properly again.

‘Initially, I was numb and in disbelief,’ she said, recalling the day she was diagnosed.

‘I feared for my life and I honestly thought my sporting days were over if I did survive this.

‘And then the thought hit me immediately — how do I tell my son? [I was scared] about not being around for him and there to watch him grow up.

‘I felt like I was letting him and my husband down.

‘I found [the size of the tumour] hard to take in, but my surgeon was very positive from the start that he could save me. I went from constantly trying to be positive to just being terrified.’

During a gruelling Ironman UK challenge, the 53-year-old sports masseuse felt a sharp and sudden pain in her abdomen, with this quickly becoming ‘excruciating’ — and she collapsed after passing the finish line

Following the event, she noticed a bulge in her belly, which after various scans, was confirmed to be retroperitoneal sarcoma — a cancerous tumour weighing a whopping 11 lbs — larger than the average newborn

Emergency surgery was carried out to remove the tumour entirely.

Due to the size, she also had to lose a kidney, adrenal gland, part of her bowel and part of her abdominal wall, as well as some of her aorta and psoas muscle.

Retroperitoneal sarcomas often cause the abdomen to increase in size, tell tale signs include a lump in the abdomen, a dull pain in the abdomen or back and intense pain with bleeding, according to Sarcoma UK. 

Around 15 per cent of all soft tissue sarcomas are found in the retroperitoneum, data suggests.

Around 3,000 patients are diagnosed with soft tissue sarcomas every year in Britain, while the figure is thought to be three times higher in the US.

Surgery is usually the main treatment for the cancer, which can involve taking part of the surrounding organs.

Ms Boswell, who initially suffered with backache and IBS symptoms, thought the bulge was simply down to her age and other symptoms due to her active lifestyle. But after her aforementioned diagnosis in August 2022, emergency surgery was carried out to remove the tumour entirely

Following her surgery Ms Boswell spent the next two months recovering in hospital, but she was determined not to give up and started small steps towards training again.

‘In hospital, when I started to walk to the toilet and back, I would time myself.

‘I’d clock the distance on my fitness watch and add a little further each day.

‘It was a triumph to walk a quarter mile down the hospital corridors.

‘It took me a year to be able to walk properly again – but after that, nothing could stop me.

‘I [began with] sitting on a static bike for 20 minutes to spin my legs and from there, I gradually built up my fitness.’

Following her surgery Ms Boswell spent the next two months recovering in hospital, but she was determined not to give up and started small steps towards training again

Now, she’s training for the next race and has also penned a book called: Ironman, Me and The Big C, to share her journey and inspire aspiring triathletes, as well as giving hope to anyone facing a similar diagnosis

She started racing again this year and has since completed a triathlon for Sarcoma UK, a charity working with those suffering from the disease, in which she took woman’s first place

She started racing again this year and has since completed a triathlon for Sarcoma UK, a charity working with those suffering from the disease, in which she took woman’s first place.

Now, she’s training for the next race and has also penned a book called: Ironman, Me and The Big C, to share her journey and inspire aspiring triathletes, as well as giving hope to anyone facing a similar diagnosis.

Ms Boswell added: ‘I really love what I do.

‘I love running and competing and being in the fresh air — it’s my medicine.

‘I have always wanted to improve myself and do the best I can.

‘I want to decide on my own terms when to stop competing — not have the decision made for me by cancer.

‘My attitude was that if I can’t run, then I’ll swim and bike instead.

‘I have to pinch myself when I look back at what I have been through.

‘I didn’t think I’d ever race again.

‘Do not make excuses for things in your health that aren’t quite right – and be grateful for everyday and the simple things in life.

‘I still have a long way to go to achieve my dreams and return to where I was.

‘But I’m loving racing again – even more than before I was diagnosed – and I look at it as a true blessing.

‘The dream is for sarcoma to never come back and for me to watch my boy grow into a man, while sharing life with my husband.’

Kerry Reeves-Kneip, director of communications and fundraising at Sarcoma UK, said: ‘Sam’s achievement is nothing short of awe-inspiring.

‘Imagine facing the shock of a 5kg sarcoma diagnosis, followed by major surgery that included losing a kidney.

‘Yet Sam didn’t just recover — she thrived, pushing herself to compete in one of the world’s most demanding sports. Her resilience and determination are truly remarkable.’