Can a blood test predict cancer recurrence? Researchers at Princess Margaret Cancer Centre in Toronto are working on a large-scale trial to determine if a blood test can detect tiny amounts of cancer remaining after treatment. Lead investigator Dr. Lillian Siu explains that smaller studies have shown evidence of cancer DNA in the blood, but large-scale studies are needed to prove it. The SHERLOCK trial is enrolling 7,000 patients who have completed cancer treatments and testing their blood for microscopic tumour DNA. If the test is positive, patients could receive experimental treatments to prevent cancer recurrence. If negative, it could indicate cancer is truly gone, allowing for reduced treatment side-effects. The trial aims to assess the test's effectiveness across different cancer types and has already gathered substantial data linking positive molecular residual disease to higher cancer recurrence rates. However, Dr. Siu emphasizes that blood tests for recurrence prediction are not yet standard care and further research is needed. The SHERLOCK study, funded by a $50-million donation, plans to follow patients for at least five years to ensure long-term outcomes. This research holds promise for easing cancer patients' fears of recurrence, but it's still early days. As one patient, Paul Lonergan, who participated in a related trial, shares his positive experience with a new immunotherapy drug, highlighting the potential benefits of this emerging technology. However, experts caution that while liquid biopsies show promise, they are not yet ready for clinical implementation and require additional trials.
