The safety net was never designed to catch everyone equally.
Three cancer patients. That's how many people from minority ethnic backgrounds have already had their chemotherapy doses adjusted since Manchester University NHS Foundation Trust quietly switched on a new genetic test last September. Three people who, under the old system, might have been sent into treatment carrying a hidden biological risk that nobody was looking for — because the test had never been designed to find it.
The NHS has now expanded its pre-chemotherapy genetic screening across England to include a fifth variant of the DPYD gene, one that is more commonly found in people of Black and minority ethnic heritage. The move corrects what amounts to a structural flaw baked into cancer care for years: the standard tests that patients receive before fluoropyrimidine-based chemotherapy were built around four DPYD variants found predominantly in white European DNA. If you carried a different variant — one more likely to appear in someone of African ancestry — the test would come back clean. Not because you were safe, but because nobody had thought to look for what you were carrying.
The consequences of that gap were not abstract. Up to 40 percent of the 38,000 patients treated annually in England with fluoropyrimidine-based chemotherapy will develop an adverse drug reaction. Those reactions range from mouth sores, nausea, and hair loss to, at the far end, death. For Black cancer patients, the risk of landing at that far end was quietly elevated by a safety net that had a hole in it shaped exactly like them.
Prof Veline L'Esperance, senior clinical adviser at the NHS Race and Health Observatory, described the expansion as the first concrete clinical response to evidence that Black and ethnic minority patients were being failed by tests built around white European genetics. The research underpinning cancer drug safety, she noted, has historically been conducted on white patients, leaving variants common in Black, African, and minority ethnic communities far less studied. The safety net, as she put it, was never designed to catch everyone equally.
What the new fifth-variant test does, in practical terms, is close one of those gaps. A patient who previously might have been falsely cleared for a standard chemotherapy dose can now be identified as carrying a variant that warrants a different starting point. In Manchester, that has already happened three times since September — three altered doses, three reduced risks, three people whose treatment was shaped by a test that finally saw them.
The announcement lands against a broader backdrop of documented inequality in cancer care for ethnic minority patients. Analysis has shown that people from minority backgrounds wait longer for a cancer diagnosis, require more GP visits before receiving one, and are less likely to feel adequately supported during hospital treatment. The genetic testing gap was one piece of a larger picture, and its correction does not redraw that picture entirely.
Prof Habib Naqvi, chief executive of the NHS Race and Health Observatory, welcomed the development while pointing toward the work that remains. Genomics and precision medicine, he said, are at the cutting edge of what medicine can do — but ethnic minority groups are under-represented both in medical research and in the genomic biobanks that fuel it. The promise of treatments tailored to individual biology only holds if the biology being studied reflects the full range of human diversity. Right now, it does not.
Prof Dame Sue Hill, chief scientific officer for NHS England, framed the fifth variant as a discovery that allows chemotherapy to be personalised more precisely — a step toward care that reduces harm rather than simply accepting it as a side effect of treatment. The North West NHS Genomic Medicine Service, she said, has already demonstrated what that looks like in practice.
The test is now available across England. The question that follows is how quickly the research pipelines feeding future tests will be redesigned to include the populations they have historically overlooked — because the DPYD fifth variant is unlikely to be the last gap that needed closing, only the first one someone looked hard enough to find.
Notable Quotes
Patients of African ancestry deserve the same standard of safety as everyone else, and now clinicians have the means to deliver it.— Prof Veline L'Esperance, senior clinical adviser, NHS Race and Health Observatory
Ethnic minority groups are under-represented in medical research and in genomic biobanks — research needs to be conducted with diverse populations before medical advances can benefit everyone.— Prof Habib Naqvi, chief executive, NHS Race and Health Observatory
The Hearth Conversation Another angle on the story
Why did it take this long to find the fifth variant?
Because the research that defines what counts as a risk was built on studies of white patients. If you're not in the data, your biology doesn't shape the test.
So the test wasn't wrong exactly — it just wasn't looking in the right places?
That's a fair way to put it. It was doing what it was designed to do. The problem is what it was designed to do was never universal.
Three patients in Manchester since September — that sounds like a small number.
It is small. But those are three people who received a different dose because of a test that finally caught something the old one would have missed. Small numbers can mean a great deal to the people inside them.
Is this the kind of fix that ripples outward, or is it more contained?
It depends on what happens in the research pipelines. The fix here is real, but the underlying problem — ethnic minorities under-represented in genomic biobanks — hasn't been solved. There are almost certainly other variants no one has studied yet.
What does it mean that this is being called the first concrete clinical response?
It means there's been a lot of conversation about health inequality in cancer care, and not much that changed what actually happens to a patient in a clinic. This changes something that actually happens.
Does the expansion of the test change anything about how patients experience the system?
For those who carry the fifth variant, yes — they get a safer starting dose. For the broader inequalities around diagnosis delays and feeling unsupported during treatment, not yet.
What should we be watching for next?
Whether the genomic research community starts building studies that include diverse populations by design, not as an afterthought. That's where the next gaps either get found or stay hidden.