A low-cost test that measures a breast cancer patient’s response to short-term hormone therapy could help predict how likely the disease is to return, researchers believe.
The scientists say the test costs around £60 per patient, which is less than 1/20th the cost of the currently available genomic tests.
It looks for changes in the growth rate of cancer cells following treatment with aromatase inhibitors – drugs which stop the production of oestrogen.
The researchers say using the test could help provide reassurance for women likely to do well on standard treatment while identifying those at increased risk of relapse.
Professor Ian Smith, honorary professor of cancer medicine at The Institute of Cancer Research in London, who is chief investigator in the trial, said: “This important trial is the largest of its kind in the world and involved around 4,500 patients in 130 NHS breast units throughout the UK.
“We have shown that giving patients with early breast cancer two weeks of simple endocrine therapy using aromatase inhibitor tablets before surgery allows us to determine what is the most appropriate medical treatment after surgery for each individual patient.
“In particular, it helps us identify which patients could avoid chemotherapy with all its unpleasant toxicities.
“The test is much cheaper and easier than current genomic tests and we believe it should become part of the standard treatment for early breast cancer.”
A team of researchers at The Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust studied women with early-stage, hormone-positive breast cancer – where cancer cells grow in response to either the hormones oestrogen, or progesterone, or both.
Two-thirds of the 4,480 patients were given one of the aromatase inhibitors, letrozole or anastrozole, for two weeks before and after their surgery.
The remaining women were treated with surgery and received the aromatase inhibitors at the usual time – only after surgery.
All patients were recommended to continue hormone treatment for at least five years as part of their standard care, which helps to reduce the risk of breast cancer coming back.
The researchers used the cancer growth rate test, which looks for the protein Ki67 in tumour samples, to see whether the pre-surgery hormone treatment had any effect.
The test allowed the team to find out which patients were at lower and higher risk of seeing their disease come back.
Professor Arnie Purushotham, Cancer Research UK’s senior clinical adviser, said: “Sadly, breast cancer can return for some women, so a new way to help predict if their cancer will return means doctors could monitor these patients more closely – catching any sign of cancer as early as possible is crucial for improving survival.
“This research could also have implications for how doctors decide to treat early-stage, hormone-positive breast cancer – potentially triaging women depending on the risk of their cancer coming back.”
The finding are published in the journal Lancet Oncology.