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Breast health 2019

Genomic testing helps women to tailor their breast cancer care

Dr Sophie McGrath

Consultant Medical Oncologist, The Royal Marsden

Genomic testing is available on the NHS and could be credited with saving thousands of women each year from chemotherapy they don’t need.

While awareness rates of breast cancer are rising, treatment plans are starting to become more tailored.

For most women, this means developing a treatment pathway based on a sample of a tumour to determine the type and aggressiveness of the tumour, but this leaves a number of patients who perhaps don’t fall into a clear category.

Erring on the side of caution, chemotherapy is often recommended, and in some cases, it would be recommended needlessly.

The Oncotype DX Breast Recurrence Score® test, however, allows the underlying gene expression of each individual patients’ tumour to be analysed to more precisely determine aggressiveness and help guide more personalised treatment decisions.

Thousands fewer women needed chemo following the study

Dr Sophie McGrath is a Consultant Medical Oncologist at the Royal Marsden Hospital, and can now offer her patients a more personalised treatment pathway.

It comes after a large data set of genomic testing – known as the TAILORx study – was published. It found that the Oncotype DX® test, a genomic test available on the NHS, can precisely determine the value of chemotherapy and identify the patients who receive no benefit from it.

When it comes to cancer there is no ‘one-size-fits-all’

The study, published in 2018, analysed data from long-term follow-up of patients who received the test. TAILORx revealed that, for some types of cancer, thousands of women are likely to be able to avoid chemotherapy every year in the UK.

That would lift a substantial burden off the NHS and make sure that women were not subjected to unnecessary overtreatment.

This has changed the way patient care is managed for Dr McGrath: “Patients who have genomic testing often feel that their treatment recommendations are more personalised. When it comes to cancer there is no ‘one-size-fits-all treatment’.”

In contrast, some women may be missing out on the chemotherapy treatment they need

The study also pinpointed that some women were undertreated and missing out on chemotherapy.

Dr McGrath explains: “Just by looking at risk factors, such as [tumour] size, grade and the age of the woman, a decision to proceed with hormones might be reached [without adding chemotherapy]. The study highlighted that for some of these women, their cancer was more aggressive than previously thought. The numbers are small, but it is something for clinicians to keep in mind when recommending genomic testing.”

Earlier this year, Dr McGrath worked on another project called PONDx, which studied roughly 600 patients. It tested the initial treatment approach of the clinician (based on a standard patient evaluation), and then re-evaluated the treatment plan once a genomic test had been completed.

While 70% of the patients were initially recommended chemotherapy, this dropped dramatically to just 27% after testing. The team is currently analysing further data and hopes to present their findings early next year.

‘Predictive’ vs ‘prognostic’ testing – understanding the jargon

For some patients, they may hear oncologists talk about predictive and prognostic tests, which can seem confusing. But Dr McGrath reveals a simple way to understand: “When you hear the word ‘predictive’, we are debating what the outcome of a therapy might be, such as whether the patient will gain a positive outcome from chemotherapy. When you hear ‘prognostic’, this is about the overall outcome and chance of recurrence, despite whatever therapies you encounter along the way.”

Other available genomic tests are prognostic only and inform patients’ risk of cancer relapse if treated without the addition of chemotherapy – not whether adding chemotherapy would be beneficial for the patient.

Oncotype DX is the only available test with proven predictive and prognostic capability, helping patients and clinicians precisely determine the likely benefit of adding chemotherapy to the treatment pathway. 

The future of breast cancer treatment is about gathering and analysing data, which will revolutionise the treatment of cancer throughout the patient journey.

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