'I've got six months to live - leaving my twin sister at 24 is unthinkable'

'I've got six months to live - leaving my twin sister at 24 is unthinkable' Caitlin Leggett is trying to raise £500,000 A 24-year-old twin given just six months to live after her leukaemia came back is attempting to raise £500,000 for potentially life-saving treatment abroad, saying the prospect of leaving her identical sister behind is "unthinkable". Caitlin Leggett, from Cardiff, was diagnosed with acute myeloid leukaemia – an aggressive cancer of the white blood cells – in April 2025, with a persistent rash being the only indication that something was seriously wrong. Following months of chemotherapy and a stem cell transplant in December 2025, Caitlin achieved complete remission. But in May 2026, doctors discovered the cancer had returned and the treatment options available to her on the NHS were unlikely to offer a cure. With only six months to live on her current treatment plan, she has chosen to seek potentially curative care overseas – most likely in the US – where treatment and related costs could amount to £500,000. Caitlin's twin sister Grace Leggett, who has given up her job as a complex care personal assistant in Bristol to return to Cardiff to be closer to her family, said witnessing Caitlin's ordeal while facing the possibility of losing her sister within six months was devastating. "We're only 24 – nobody expects this to happen... Being twins as well, you're not supposed to have one twin not be there," Grace said. "It's unthinkable," Caitlin added. "We've gone through life together and I don't want our story to end here." Caitlin and Grace have always been incredibly close – even sharing a student house together at the University of Bristol. Following graduation in July 2024, Caitlin had intended to enlist in the Army, aspiring to train as an intelligence officer. She had her mandatory medical assessment scheduled for April 2025, but in March of that year she said she developed a rash that wouldn't disappear despite using over-the-counter creams from the chemist. A few weeks afterwards, she said she visited her GP, who suspected she might have a virus and requested some blood tests to examine further, which were taken on April 3, 2025. She said she was told to report to the Llewellyn Teenage Cancer Trust unit at University Hospital of Wales in Cardiff the next day, and instantly realised it wasn't good news. At the appointment on April 4, 2025, she was diagnosed with acute myeloid leukaemia (AML) – an aggressive cancer of the white blood cells. According to the NHS, symptoms of AML can include looking pale, feeling tired or weak, breathlessness, unusual and frequent bruising or bleeding, and losing weight without trying to, but Caitlin said she experienced none of these – just the unusual rash, which can also be a sign of blood cancer. After discovering that treatment would involve a stem cell transplant, replacing the destroyed cancerous cells with healthy stem cells from a donor, the twins' entire family was tested to determine if any of them could be a match. According to blood cancer and blood disorder charity DKMS, more than 2,000 people every year in the UK require a blood stem cell transplant, yet just 7% of the entire eligible population in the UK are registered as potential donors. Both Caitlin and her sister Grace had signed up as stem cell donors "years and years ago", and Grace was initially told she would likely be a match for her sister. Throughout their lives, they had believed themselves to be fraternal twins, meaning there was a strong possibility that Grace's stem cells would be accepted by Caitlin's body and assist in her recovery. However, genetic testing in June 2025 revealed they were actually monozygotic twins — meaning they were identical. "I always wished I was an identical twin – I liked being a twin, but being an identical twin is a bit cooler," Grace said. "It's really weird to think that I'm basically Caitlin!" This discovery proved to be a significant setback for Caitlin's treatment — due to their near-identical DNA, Caitlin explained that "the whole concept of the transplant wouldn't work" as the body must recognise the stem cells as foreign in order for them to fight the cancerous cells. Sadly, no other family members proved to be a match either. While awaiting an alternative donor from the register, Caitlin achieved remission in May 2025 following two months of chemotherapy. However, in August 2025, she was informed that the cancer had returned to her skin – an unusual relapse which, she said, was worsened by challenges in locating a suitable stem cell donor. Caitlin subsequently participated in a menin inhibitors clinical trial in Manchester to eradicate the leukaemia in her skin, which proved successful and placed her into complete remission – precisely what her consultants required before her stem cell transplant, as it provides a greater chance of success. She was given another transplant date in December 2025 with a different donor. However, a week prior to this second transplant date, the cancer reappeared in her skin. She was still able to undergo the transplant, which occurred in December 2025, but required additional full-body radiotherapy beforehand. The treatment was considered successful and she was informed she was in remission once more in January 2026. Caitlin was subsequently scheduled for monthly bone marrow monitoring for three months, to verify that the cancer had not returned, which were due to decrease to quarterly tests from March 2026, "but I wasn't too happy about that", she explained. "I didn't feel like it was safe to just go straight to three, so I persuaded my consultant to give me an extra one in May," she said. "On that extra one, they found that the leukaemia had come back. Initially, the blast count came back at 5.7%, just over remission, but then about a week later it went up to 37%. So it's quite fast-growing." From May 2026, Caitlin has been participating in a further drug trial for Bleximenib and is awaiting news on whether her body responds positively. Her medical team say there is another drug trial option should it prove unsuccessful – however she has been advised that these treatments are not curative. She has been informed that a second stem cell transplant cannot be carried out in the UK, and doctors have predicted that her current treatment plan will keep her alive for just six more months. As a result, she has chosen to seek curative treatment overseas – weighing up specialised leukaemia treatment in America or CAR-T cell therapy, a form of immunotherapy, in either China or Singapore, both of which will run into hundreds of thousands of pounds. Caitlin and Grace have launched a GoFundMe page entitled Saving Caitlin in a bid to raise £500,000 to meet the cost of the expensive overseas treatment, along with transport, accommodation and sustenance for accompanying family members, and are "appealing to anyone and everyone to help us in this fight". Should the twins fail to raise the necessary funds, it is unlikely that Caitlin will survive to celebrate her 25th birthday. "It's incredibly difficult to think about," Caitlin said. "At 24, I always assumed I had my whole life ahead of me. There are so many things I still want to do, places I want to see, and memories I want to make with the people I love. "What I would miss most isn't one particular event, it's the chance to keep living an ordinary life with the people I love and growing older alongside my twin sister. Those are the things that matter most to me, and that's why I'm doing everything I can to find another treatment option. I don't want to miss out on the future we always thought we'd share together." You can support Caitlin's fundraiser by visiting her page.