The world’s largest and most advanced single-site radiation medicine program

Dr. Fei-Fei Liu leads the Radiation Medicine Program at The Princess Margaret—the largest single-site radiation program in the world and one of the most innovative. In this area of cancer therapy, precision is critical, as radiation has the potential to impact all of the treated area, including the cancer and the surrounding healthy tissue. 

The medical physics team, in collaboration with radiation oncologists and therapists, has increased the precision for all types of radiation therapy; in some cases targeting tumor tissue in high risk areas such as the brain to within one millimeter.

“As we strive to set a new gold standard for patient care with Personalized Cancer Medicine,” says Dr. Liu, “The Princess Margaret is pioneering a new area called adaptive radiation therapy where a patient’s treatment plan is adapted depending on how they are responding in each treatment session.  This requires sophisticated hardware and software systems, along with the expertise to image and track patient progress in a highly efficient way.  The Princess Margaret is one of the few places in the world where these new procedures are being developed and tested.”
Regenerative radiation medicine
Minimizing side effects of cancer therapy is always a top priority for the clinicians at Princess Margaret Cancer Centre.  “In our radiation medicine program, we have integrated imaging into all of our procedures to more precisely target radiation only to the tumor, minimizing the impact on healthy tissues,” explains Dr. Liu. “But we are also exploring how tissue and organ damage that cannot be avoided could be repaired.”

For example, radiation fibrosis (or tissue thickening) may appear months or even years after treatment, and is currently irreversible. This side effect results from a complex process of inflammation, reduced blood flow and oxygen, and excess wound healing at the irradiated site.  Researchers at The Princess Margaret are trying to reverse radiation fibrosis in the laboratory by using stem cells derived from fat tissue with some promising results.

Princess Margaret Cancer Centre is where stem cells were originally discovered 55 years ago.  These important cells, which exist throughout our body, are key factors in healing and in the natural renewal that our body requires. Our researchers are exploring how we might harness stem cells in repairing damage that can be caused by radiation therapy. As part of the University Health Network, the researchers at The Princess Margaret are able to tap into and collaborate with some of the world’s top minds at the McEwen Centre for Regenerative Medicine.
Tumor Microenvironment
It is understood by oncologists today that radiation is not as effective for tumors that are growing in hypoxic (low oxygen) environments.  Our clinical team is leading several important studies that are testing ways to overcome hypoxia in tumor environments in order to maximize the impact of radiation.