Thousands of women with breast cancer may benefit from genetic tests – study

More than 15,000 women a year who have breast cancer in the UK would benefit from tests that analyse DNA for changes or mutations, a study has suggested.

Having a patient’s entire genetic readout using whole genome sequencing could help guide personalised treatments and open up recruitment to clinical trials, according to researchers.

Whole genome sequencing is a technique that allows medics to looks at a person’s entire genetic code from a blood test, looking for anything unusual that might be causing problems.

Currently in England, the NHS Genomic Medicine Service is used to detect rare and inherited diseases, paediatric cancers and certain adult cancers.

However, experts at the University of Cambridge suggest the programme is “not being used to its full potential”.

For the study, researchers analysed 2,445 breast cancer tumours collected from 2,403 patients from across 13 NHS Genomic Medicine Centres or hospitals involved with the 100,000 Genomes Project – led by Genomics England in partnership with NHS England.

The team looked for genetic changes that cause or influence breast cancer, such as problems in the way cells repair DNA.

According to the analysis, some 27% of breast cancer cases had genetic features that could support personalised treatment or recruitment to clinical trials.

Researchers suggest this equates to more than 15,000 women a year in the UK.

The features identified in the tumours included DNA repair issues found in 12% of all breast cancers, known as HRD (homology-directed repair deficiency), as well as signs of resistance to hormone therapy, and unique mutations that could be targeted with drugs.

Professor Serena Nik-Zainal, of the Department of Genomic Medicine and Early Cancer Institute at the University of Cambridge, said: “It is becoming increasingly possible to use whole genome sequencing to inform cancer management, but it’s arguably not being used to its full potential, and certainly not for some of the more common types of cancer.

“Part of the reason why is because we lack the clinical studies to support its use, but it’s also in part precisely because the information is so rich – in a sense, the information can be too overwhelming to make sense of.”

Researchers said that while genomics has “begun to inform cancer management”, some argue it has “under-delivered on the promise of personalised medicine”.

At the moment, decisions on breast cancer treatment can be made by testing patients for the presence of certain gene mutations, such as BRCA1 and BRCA2.

However, experts highlight that a human cancer genome does not just carry one or two driver mutations, but thousands.

Researchers said the findings, published in the Lancet Oncology, could “massively open up” recruitment to clinical trials and personalised therapies for women with breast cancer.

“At the moment, we test patients for just a small number of genetic mutations and may invite them to join a clinical trial if the patient has a mutation that matches the trial’s target,” Prof Nik-Zainal said.

“But if we have their entire genetic readout instead, we will no longer be restricted to single trials with a specific target.

“We could massively open up the potential for recruitment, to multiple clinical trials in parallel, making recruitment to clinical trials more efficient, ultimately getting the right therapies to the right patients much faster.”

Prof Nik-Zainal said the UK “is a genuine world-leader in terms of its ability to do whole genome sequencing in the NHS through the Genomic Medicine Service”.

She added: “Now that we have population-level evidence of how impactful whole-genome sequencing could be, we have the potential to make a difference to thousands of patients’ lives every year, helping tailor their care more precisely, giving more treatment to those who need it and less to those who don’t.”

Breast cancer is the most common cancer in the UK, with around 56,000 new cases every year.

Prof Matt Brown, chief scientific officer at Genomics England, said: “Rapid advances in genomics are already ushering in the next generation of personalised cancer medicine.

“Not only can a patient’s genes guide precision treatment decisions that will best serve them, but we could improve how we match people up to clinical trials and help more patients access innovative treatments.

“Research like this highlights the value of the National Genomic Research Library and how understanding our genes can provide a real boost to the way we diagnose and treat disease.”

Dr Kotryna Temcinaite, senior research and impact communications lead at the charity Breast Cancer Now, said: “There is already some testing in place to help ensure people diagnosed with breast cancer are given the most effective treatment for them.

“But this study points towards a potential opportunity to develop even more precise, effective and personalised treatments over time for everyone affected by breast cancer.”