Thousands of cancer patients from minority ethnic backgrounds will have access to “groundbreaking” genetic testing on the NHS that previously discriminated against them.

This routine form of genetic testing, used before chemotherapy treatment, could save the lives of Black and minority ethnic cancer patients who already face poorer health outcomes after diagnosis compared with their white counterparts.

Before undergoing chemotherapy, cancer patients across England undergo genetic testing to reduce the adverse side effects the treatment can have, which includes mouth sores, hair loss, nausea, fatigue and death. Up to 40% of the 38,000 patients treated with fluoropyrimidine-based chemotherapy in England will develop an adverse drug reaction to the treatment.

Until last year, these genetic tests only looked for four types of DPYD gene variants, which are mainly found within the DNA of people from white European backgrounds. Consequently, this genetic testing was less effective on Black cancer patients, leading them to be more likely to experience severe side effects including death after chemotherapy.

These genetic tests are now being offered by the NHS across England to include testing for a fifth DPYD genomic variant, which is more prevalent among people from Black and minority ethnic backgrounds. Before this fifth variant was introduced, Black cancer patients could falsely be given the all-clear on their chemotherapy dosage because the genetic test was never designed to find the variant they were carrying.

Prof Veline L’Esperance, the senior clinical adviser at the NHS Race and Health Observatory, said that the introduction of these new genetic tests represents “tangible results for patients who have historically been left behind”.

“Patients of African ancestry deserve the same standard of safety as everyone else, and now clinicians have the means to deliver it,” L’Esperance said. “What makes this significant is that it moves the conversation about ethnic health inequality in cancer care from words to action. This is the first concrete, clinical response to the evidence that Black and ethnic minority patients were being failed by tests designed around white European genetics.”

“The research that underpins cancer drug safety testing has historically been done on white patients. Variants more common in Black, African and minority ethnic communities have been studied far less which means the safety net has never been designed to catch everyone equally.”

Since the test went live at Manchester University NHS Foundation Trust last September, three cancer patients from minority ethnic backgrounds have undergone this new genetic testing and consequently received altered starting doses of chemotherapy which reduced their risk of a potentially fatal reaction to the drugs.

Black and Asian cancer patients face various inequalities in regards to their health outcomes and care. Previous analysis has found that people from ethnic minority backgrounds wait longer for a cancer diagnosis than their white counterparts, require more visits to the GP before receiving a diagnosis, and also are less likely to feel they are receiving adequate support while receiving cancer treatment in hospital.

Prof Habib Naqvi, the chief executive of the NHS Race and Health Observatory, said the introduction of the new genetic testing is a “groundbreaking outcome in the use of chemotherapy, which is already having a positive impact on patients’ lives.”

Naqvi added: “Genomics and precision medicine are currently at the cutting edge of medical technology, promising a world in which treatments can be more targeted and effective. However, we also know that ethnic minority groups are under-represented in medical research and in genomic biobanks. Research needs to be conducted with diverse populations – only then can medical advances benefit everyone.”

Prof Dame Sue Hill, chief scientific officer for NHS England and senior responsible officer for NHS Genomics, said: “It is fantastic news that we have now discovered a fifth gene variant that allows chemotherapy to be personalised, helping us to deliver more tailored care and reduce harmful side effects, which could be lifesaving for cancer patients with this gene.

“The North West NHS Genomic Medicine Service has already shown how this can improve treatment for patients of African ancestry, building on the NHS’s firm commitment to reducing race and health inequalities in cancer care, ensuring no patient is disadvantaged by lack of access or opportunity.”