How Canadian researchers are using 'liquid biopsies' to find traces of tumours left after cancer treatment

A Toronto-based research team is launching a years-long study of liquid biopsies—blood tests that detect tumour DNA invisible to traditional scans—to help cancer survivors avoid recurrence and spare some from costly, invasive treatments. Patient Paul Lonergan's case shows the technology detected residual cancer that allowed him to receive immunotherapy and achieve cancer-free status.

The technology remains largely confined to clinical trials and private clinics; widespread access depends on successful completion of the research project.