A new blood test can predict the risk of breast cancer returning three years before any tumors show up on scans in an “incredibly exciting” breakthrough that could help more women beat the disease for good.
More than 2 million women are diagnosed each year with breast cancer, the most common type of the disease. Although treatment has improved in recent decades, the cancer often returns, and when it does, it is usually at a more advanced stage.
But now research presented at the world’s largest cancer conference has shown that a personal liquid biopsy can provide a very early warning sign that cancer is returning. Results of a trial of the tests, revealed at the annual meeting of the American Society of Clinical Oncology in Chicago, suggest that they can help reveal which women need preventive therapy and which patients can be spared it.
The test detects minuscule amounts of cancer DNA in the bloodstream. Trial results show that it is so sensitive that it can accurately predict the risk of cancer coming back months or even years before the usual signs or symptoms start to appear.
Researchers at the Breast Cancer Now Toby Robins research center in London were able to identify every patient in the trial who later relapsed. The average time to relapse was 15 months; the longest 41 months.
“Early detection is one of our best weapons against breast cancer and these initial findings, which suggest that tests can detect signs of breast cancer recurrence more than a year before symptoms, are incredibly exciting,” said Simon Vincent, Director of Research at Breast Cancer Now, that helped fund the trial.
“While this research is still in its early stages, the incidence of breast cancer recurrence means earlier, the treatment is much more likely to destroy the cancer and prevent it from spreading to other parts of the body, and then it becomes incurable .”
Experts hope the findings will lead to a strategy in which treatment can be started much earlier. The ultra-sensitive liquid biopsy works by finding circulating tumor DNA (ctDNA) released by cancer cells into the bloodstream.
“Breast cancer cells can remain in the body after surgery and other treatments, but there may be so few of these cells that they are undetectable on follow-up scans,” said Isaac Garcia-Murillas, the study’s lead author at the Institute for Cancer Research (ICR) in London. . “These cells can cause breast cancer patients to relapse many years after their initial treatment.”
Previous research has suggested that ctDNA blood tests can identify relapse before it can be seen on a scan. However, these tests tend to use a technique called whole exome sequencing that usually looks for between 16 and 50 mutations. The new test uses whole-genome sequencing and looks for 1,800 mutations, making it much more sensitive.
Researchers analyzed blood from 78 patients with different types of breast cancer. The new test correctly flagged a high risk of recurrence in all 11 of the patients who relapsed during the five-year trial. All 60 women in whom the test did not find ctDNA did not relapse, meaning there were no false negatives either.
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Another three patients had ctDNA detected once, but further testing showed that it had disappeared. The ICR did not provide complete data for the remaining four patients.
Prof Kristian Helin, the ICR’s chief executive, said: “Breast cancer is much easier to treat before it spreads to other parts of the body, so it is essential to detect signs of recurrence as early as possible to give people the best to give chance of survival.
“It is very exciting to see advances in technology that can detect cancer cells and DNA with greater sensitivity to pick up residual disease or detect the early signs of breast cancer recurrence while a cure is still possible. These approaches are having a transformative effect on cancer diagnosis.”
