A test that can quickly predict how people with leukaemia will respond to chemotherapy could change how some cancers are treated, according to researchers.

The BBC reports scientists at Cardiff University said the accurate test could help guide doctor’s decisions on which drugs to give patients. They said it could also improve the care given to other patients, like those with myeloma and breast cancer.

Leukaemia is a blood cancer that can affect the immune system. The most common type, chronic lymphocytic leukaemia (CLL), is a slowly developing cancer in which people produce mutated versions of white blood cells that build up in the blood, bone marrow and lymph nodes and crowd out healthy blood cells. CLL progresses at different rates in different people and never progresses at all in a third of cases.

Until now there has been no accurate test that can be used to indicate if and how fast an individual’s cancer will develop, but the results of the new test can be ready in a day.

The high throughput “STELA” test developed at Cardiff University measures the length of sections of DNA in cancer cells called telomeres, which are found at the end of chromosomes. Telomeres act in the same way as protective plastic tips on the end of shoelaces, preventing chromosome ends from “fraying.”

Telomeres shorten every time a cell divides to create a new cell and eventually the chromosome ends are left exposed, leading to extensive DNA damage that speeds up cancer progression.

The researchers have shown people who have very short telomeres when they are diagnosed are much more likely to have a fast progressing cancer.

The improved STELA test was used to analyse samples from two hundred and sixty people to see if it could predict how they would respond to intensive chemotherapy combined with immunotherapy. The test showed people with short telomeres relapsed much sooner after treatment than those with long telomeres, on average 3.7 years after treatment compared to 5.5 years.

People with cancer cells containing mutations to the IGHV gene are known to have a better outcome than people without this genetic mutation. The STELA test was found to be a more accurate predictor of relapse than testing for the IGHV mutation or any other current prognostic or predictive test.

Professor Duncan Baird, who developed the test at Cardiff University’s School of Medicine with Professor Chris Pepper and Professor Chris Fegan, said “Not all patients benefit equally from chemotherapy and this test is the only one available that can accurately predict how patients are likely to respond. Our research provides strong evidence that a significant number of patients should be receiving more appropriate treatments.”

The research, funded by blood cancer research charity Bloodwise, has been published in Leukemia.

Dr Alasdair Rankin, director of research at Bloodwise, said “People with CLL can experience great anxiety and uncertainty about how their cancer will progress. This test could give people the peace of mind that they will receive the most effective treatment possible if it does. It may even allow some people to be told that their cancer is unlikely to progress.”

This article was updated on March 4th 2019 to include additional information from Cardiff University.