Isla Sneddon: Teen Dies 6 Months After Cancer Diagnosis

A family in the United Kingdom is advocating for changes to medical protocols after their 17-year-old daughter, Isla Sneddon, died of breast cancer. The case highlights the challenges in diagnosing cancer in young adults and the potential for delayed diagnoses when symptoms are initially attributed to other causes.

Isla first noticed a lump in her breast at the age of 15. Initial consultations with doctors led to reassurance that the lump was likely benign and related to hormonal fluctuations, a common occurrence in teenagers. According to her parents, Mark and Michelle Sneddon, this initial assessment led to a delay in further investigation.

Despite continued concerns, a biopsy wasn’t recommended until Isla was 17. However, even then, the referral for the biopsy was downgraded due to her age. It was only after this delay that Isla received a diagnosis of breast cancer. Tragically, by the time of diagnosis, the cancer had progressed, and her family was informed she had only six months to a year to live. Isla died in March 2025, six months after her diagnosis, at the age of 17.

The Sneddon family believes that if Isla had been an adult presenting with the same symptoms, her case would have been investigated more thoroughly and potentially, the cancer could have been detected earlier, leading to a more favorable outcome. “We trusted what we were told,” Mark Sneddon stated. “We believe that if Isla had been an adult presenting with the same symptoms, there would be a lot more done. There would have been a longer investigation – she wouldn’t have been told it was something she’d grow out of. We’ll never know, but we believe that if that had been caught then, it maybe wouldn’t have got to where it was.”

The family’s experience has prompted them to campaign for a change in the law, aiming to ensure that young people presenting with potential cancer symptoms are treated with the same urgency and thoroughness as adult patients. They are petitioning the Scottish government for an overhaul in treatment for pediatric cancer patients. Mark Sneddon expressed his hope that their efforts will prevent other families from experiencing the same heartbreak: “I don’t want another father or mother to feel like we do. We’re empty, we’re lost – I would never wish this on another family. If this gets passed, it can save another child from going through what Isla went through.”

Isla is described by her parents as a bright, bubbly, and humorous young woman who was adored by her family. They emphasize the devastating loss of her potential and the importance of ensuring that other young people have the opportunity to live full lives. “Isla was the best daughter you could ask for,” Mark Sneddon said. “She was bright and bubbly. She had a really good sense of humour, and she was beautiful. Me and her mum adored her – we just wanted her to have the best life she could have.”

The case raises important questions about the challenges of diagnosing cancer in adolescents and young adults. While cancer is often associated with older individuals, it can occur at any age. Symptoms in younger patients may be dismissed or attributed to other, more common conditions, leading to delays in diagnosis and treatment. This can be particularly problematic for rarer cancers, such as breast cancer in young women, where awareness may be lower among both patients and healthcare providers.

The Sneddon family’s fight for change underscores the need for increased awareness of cancer symptoms in young people and for healthcare professionals to consider cancer as a possibility, even in patients who may be considered “too young” to be at risk. Their advocacy efforts could lead to improved diagnostic pathways and better outcomes for young people diagnosed with cancer.

As of February 5, 2026, the family continues to push for legislative changes in Scotland. Their story has gained attention in the media, including coverage from People, The Sun, Mirror, and on Facebook via PlymouthLive.