Tens of thousands of breast cancer patients could be saved from undergoing gruelling chemotherapy with a new test which shows whether drugs will be effective.
Many women with early stage breast cancer get no benefit from chemotherapy after having surgery and radiotherapy but some still receive treatment to be on the safe side.
Now a new test has found to be effective at predicting which patients can be spared treatment.
MammaPrint is a new genomic test which scientists claim is able to accurately predict the risk of cancer recurrence for early-stage, hormone-receptor-positive and negative disease.
In so doing, women identified as low-risk could safely avoid gruelling rounds of chemotherapy without significant risk of their cancer returning.
The test looks at 70 genetic variants which control the growth and spread of cancer, The Telegraph reported. By measuring the activity of these genes, clinicians can identify women with a low risk of recurrence who would have little to gain from receiving chemotherapy after treatment with surgery and radiotherapy.
The study, looking at the accuracy of MammaPrint, is one of the largest and most rigorous trials of genomic testing and looked at nearly 7,000 women over a five year period across 112 hospitals in Europe, including Edinburgh, Sheffield, London and Bristol. They found that MammaPrint provides an accurate, definitive assessment of the risk of breast cancer recurrence. Meaning oncologists and patients can make better-informed decisions about the need for chemotherapy.
“More and more evidence is mounting that there is a substantial number of women with breast cancer who will not need chemotherapy to do well,” said Dr Rachel A. Freedman, a breast cancer oncologist at the Dana-Farber Cancer Institute in Boston, USA. She was not involved in the study.
The researchers who tested MammaPrint, estimate that their findings could apply to 40,000 women per year in the United States, and 70,000 per year in Europe. These would be women who caught the disease early but because of their tumor size, cancerous lymph nodes and other factors would normally be prescribed chemotherapy.
“MammaPrint is already enabling thousands of patients with early stage breast cancer to safely forego the rigours of chemotherapy across the world.”
In the UK, the test which costs around £2,000 is currently only available privately, but the National Institute of Health and Care Excellence (NICE) is in talk with the company behind the test, Agendia, to see if it can be provided free of charge on the NHS. Currently the NHS uses the OncotypeDX test.
In the States, MammaPrint costs around $2,650 and insurance coverage varies. Even in the States, OncotypeDX remains the most commonly used test for breast cancer recurrence.
Whilst many scientists have praised the study, claiming “it will help more patients avoid the toxicities of chemotherapy (potentially including permanent nerve damage, heart failure, and leukemia),” it’s important to note that there was a 1.5% decrease in recurrence rates for low-risk women who received chemo compared with those that did not (99.4% vs. 95.9%).
The researchers leading the trial said that the study was not large enough to be sure whether the 1.5-percentage-point difference was significant.
Dr Fatima Cardoso, the first author of the study and a breast oncologist at Champalimaud Clinical Center in Lisbon, said: “We have to continue to follow these patients and see what happens at 10 years.”
Other similar tests have reported data for at least 10 years, and MammaPrint will now need to be subject to the same level of scrutiny.
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