Researchers at UHN's Princess Margaret Cancer Centre have launched a landmark study, known as SHERLOCK, that uses a blood test to detect small traces of cancer that may remain in a patient's body after treatment.
The traces are known as molecular residual disease (MRD), small cancer signals in the blood often not detected with standard testing methods, such as CT or MRI scans, or even more invasive tests like tissue biopsies.
Finding these early clues through liquid biopsies may help determine whether a cancer is likely to return, allowing doctors to monitor patients more closely and consider next steps sooner.
SHERLOCK is a flagship initiative of the Peter Gilgan Centre for Early Cancer Detection Research, a new hub founded with a $50-million donation from the Peter Gilgan Foundation to advance technologies that can detect cancer earlier and improve patient outcomes.
"For patients who have already undergone curative cancer treatment, a question often lingers: Is the cancer truly gone?" said Dr. Lillian Siu, senior scientist at UHN's Princess Margaret Cancer Centre and a scientific lead at the Peter Gilgan Centre for Early Cancer Detection Research.
"Our hope is that studies like SHERLOCK will bring us much closer to answering that question with confidence and, ultimately, prevent cancers at high risk of relapse from returning."
The study will follow 7,000 patients who have completed cancer treatment, creating what is expected to become the world's largest dataset of its kind.
Cancer recurrence remains one of the biggest challenges in oncology. Doctors typically rely on scans or clinical symptoms to detect relapse, but, by then, the cancer may have already been growing for months or years.
Tailored cancer treatments
The research seeks to bring new insights and precision to the fight against cancer.
For example, clinicians may be able to individually tailor cancer care for their patients — intensifying treatment when cancer is likely to return or scaling back when it is not needed — reducing unnecessary side effects.
By studying blood samples from patients after treatment, researchers will collect unprecedented data across many types of cancer, including both solid tumours and blood cancers.
The resulting cohort will support a series of future clinical trials designed to evaluate how MRD detection can guide treatment decisions.
"The ability to detect trace amounts of cancer that remain after therapy creates an entirely new option for better and more effective treatments," said Dr. Brad Wouters, Executive Vice-President of Science and Research at UHN.
"With SHERLOCK, early detection creates the exciting possibility of intercepting and preventing cancer recurrence with many types of new therapies."
Beyond patient care, the SHERLOCK study is expected to create a powerful engine for scientific discovery and innovation by generating large-scale genomic datasets critical to the development of novel diagnostic technologies.
