Researchers at Toronto's Princess Margaret Cancer Centre have launched a major trial to determine if a simple blood test can predict cancer's return.
The SHERLOCK study will enroll 7,000 patients who have completed cancer treatment. Scientists will analyze their blood for microscopic amounts of tumor DNA, a signal known as molecular residual disease.
"The goal is to build evidence that could ease one of the biggest fears of cancer patients: that their cancer will come back," said lead investigator Dr. Lillian Siu.
If the test is positive, patients could receive additional experimental immunotherapies. If negative, it may indicate the cancer is gone, potentially sparing patients from further chemotherapy or radiation side effects.
The trial, funded by a $50 million donation from the Peter Gilgan Foundation, will follow patients for at least five years to validate long-term outcomes.
While promising, experts caution that liquid biopsies are not yet standard care. "This is an observational study," noted Dr. Gillian Vandekerkhove of the University of British Columbia. "Additional trials will be needed."
One patient, Paul Lonergan, credits a similar earlier study with saving his life. After treatment for throat cancer, a blood test found residual disease. He was given an immunotherapy drug in a trial. "Sure as heck it worked," Lonergan said. He's now back on the ice playing hockey.