Identical twin fears leaving sister alone after being given just six months to live
A woman who has been given just six months to live has shared her fears of leaving her identical sister alone.
Caitlin Leggett, 24, from Cardiff, was diagnosed with acute myeloid leukaemia, an aggressive cancer of the white blood cells, in April last year.
Symptoms usually include looking pale, feeling tired or weak, breathlessness, unusual and frequent bruising or bleeding, and losing weight without trying, according to the NHS.
However Caitlin said she experienced none of these and the only sign something was wrong was an unusual rash, which can also be a sign of blood cancer.
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After months of chemotherapy and a stem cell transplant in December 2025, Caitlin achieved complete remission.
But in May 2026, she said doctors found the cancer had returned, and the treatment options available to her in the UK were unlikely to be curative.
Having been given just six months to live on her current treatment plan, she has decided to pursue potentially curative treatment abroad, most likely in the US, where treatment and associated costs could reach £500,000.
Caitlin’s twin sister Grace Leggett, who has quit her job as a complex care personal assistant in Bristol to move back to Cardiff to be closer to her family, says watching Caitlin go through treatments is incredibly painful.
“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 told PA Real Life.
“It’s unthinkable,” Caitlin added.
“We’ve gone through life together, and I don’t want our story to end here.”
After her diagnosis in April last year, Caitlin learned that her treatment would involve a stem cell transplant, replacing the destroyed cancerous cells with healthy stem cells from a donor, the twins’ whole family was tested to see if any of them could be a match.
According to blood cancer and blood disorder charity DKMS, more than 2,000 people each year in the UK need a blood stem cell transplant, but just 7% of the entire eligible population in the UK are registered as potential donors.
Both Caitlin and her sister Grace had registered as stem cell donors 'years and years ago', and initially Grace was told that she would likely be a match for her sister.
They had believed that they were fraternal twins, meaning there was a high chance that her stem cells would be accepted by Caitlin’s body and would aid her recovery.
But genetic testing in June 2025 revealed they were actually monozygotic twins, meaning they were identical.
This discovery meant a setback for Caitlin’s treatment, because they have near-identical DNA, Caitlin said 'the whole concept of the transplant wouldn’t work' as the body has to recognise the stem cells as foreign in order for them to combat the cancerous cells. Unfortunately, no other family members were a match, either.
Doctors discovered in May that the cancer had returned and was growing quickly.
From May 2026, Caitlin has taken part in another drug trial for Bleximenib and is waiting to see whether her body responds.
She said she has been told that a second stem cell transplant cannot be performed in the UK, and doctors have predicted that her current treatment plan will help her survive for just six more months.
She has decided to pursue curative treatment abroad – she is considering specialised leukaemia treatment in America or CAR-T cell therapy, a type of immunotherapy, in China or Singapore, both of which will cost hundreds of thousands of pounds.
Caitlin and Grace have set up a GoFundMe page titled Saving Caitlin to try and fundraise £500,000 to cover the cost of the treatment, as well as transport, accommodation, sustenance for accompanying familyy members too.
“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.”
You can donate to Caitlin’s fundraiser here.
Greg Harris