Research conducted by The Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust has exhibited the efficacy of a liquid biopsy test to identify genetic mutations responsible for breast cancer drug resistance.
The test identifies low levels of cancer DNA in the blood which can predict the likely response of women to current hormonal treatments and new drugs.
It detects mutations to a gene called oestrogen receptor 1, or ESR1 indicative of the fact that receptors for the female hormone oestrogen in the cancer cells characteristically stay permanently switched on without it.
The research was funded by Le Cure, supporters of The Royal Marsden Cancer Charity, and the Medical Research Council which demonstrated the mutation detecting blood test for breast cancer drug resistance in a cheaper and simpler way.
The first trial examined 162 patient blood samples and detected mutations in the oestrogen receptor.
The patients exhibiting the mutation responded better with a delayed progression of the disease when treated with oestrogen receptor protein degrading drug, fulvestrant.
Women without ESR1 mutations responded in a similar manner to the conventional aromatase inhibitor drug, exemestane and fulvestrant.
The Institute of Cancer Research, London molecular oncology team leader The Royal Marsden NHS Foundation Trust consultant medical oncologist and study leader Dr Nicholas Turner said: “Our results show that breast cancer with and without ESR1 mutations are distinct subtypes that respond differently to treatment.
“These subtypes can be diagnosed simply and cheaply from a blood test, and should be considered for future clinical trials of advanced breast cancer to ensure patients are receiving the best treatment for their cancer.
“For the first time we should able to use a potentially simple test to help us pick the best treatment for women with advanced cancer after their initial treatment has failed.
"We do need to confirm the results in another trial before we can implement this clinically.”