New 'Mutation-Tracking' Blood Test Could Predict Breast Cancer Relapse
Scientists have developed a blood test for breast cancer that may be able to identify which patients will suffer a relapse after treatment, months before tumors are visible on hospital scans. The test may uncover small numbers of residual cancer cells that have resisted therapy by detecting cancer DNA in the bloodstream. The results of the study were published by Garcia-Murillas et al in Science Translational Medicine.
Researchers at The Institute of Cancer Research (ICR) and The Royal Marsden NHS Foundation Trust were able to track key mutations that cancer accumulates as it develops and spreads, without the need for invasive biopsy procedures. They hope that by deciphering the DNA code found in blood samples, it may be possible to identify the particular mutations likely to prove lethal to that patient and tailor treatment accordingly.
The study is an important step toward the use of “liquid biopsies” to revolutionize breast cancer care, by changing the way cancer is monitored in the clinic and informing treatment decisions.
Study Details
Researchers took tumor and blood samples from 55 patients with early-stage breast cancer who had received chemotherapy followed by surgery and had potentially been cured of their disease.
By monitoring patients with blood tests taken after surgery and then every 6 months in follow-up, the researchers were able to predict accurately who would suffer a relapse. Women who tested positive for circulating tumor DNA had a 12-fold risk of relapse compared with those who tested negative, and the return of their cancer was detected an average of 7.9 months before any visible signs emerged.
The researchers used a technique called “mutation tracking,” developing a digital polymerase chain reaction (PCR) test personalized to the mutations found in an individual patient's cancer to identify tumor DNA in the bloodstream. Because the researchers at the ICR and The Royal Marsden were looking for mutations common to many types of breast cancers, they found the test could be applied to all breast cancer subtypes.
The research also showed how genetic mutations build up in cancer as it develops over time, as the leftover cancer cells grow and spread. This process reinforces the importance of detecting recurrence early, so patients can have treatment before additional mutations emerge.
Hope for Future Place Within Testing
Nicholas Turner, MD, PhD, team leader in molecular oncology at The Institute of Cancer Research and consultant medical oncologist at The Royal Marsden NHS Foundation Trust, said, “We have shown how a simple blood test has the potential to accurately predict which patients will relapse from breast cancer, much earlier than we can currently. We also used blood tests to build a picture of how the cancer was evolving over time, and this information could be invaluable to help doctors select the correct drugs to treat the cancer. Ours is the first study to show that these blood tests could be used to predict relapse," he said.
"It will be some years before the test could potentially be available in hospitals, but we hope to bring this date closer by conducting much larger clinical trials starting next year. There are still challenges in implementing this technology, but digital PCR is relatively cost-effective and the information that it provides could make a real difference to breast cancer patients,” added Dr. Turner.
Dr. Turner is the corresponding author for the Science Translational Medicine article.
The study was supported by the NIHR Biomedical Research Centre at The Royal Marsden and The Institute of Cancer Research, Breast Cancer Now, and Cancer Research UK.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
