New immune-targeting approach could prevent cancer recurrence after surgery

When cancer is caught early and surgeons can remove the whole tumour, a lasting cure is often possible. 

After decades of research, scientists now understand that a cure often depends not only on a successful surgery, but also on the ability of the immune system to find and kill any remaining hidden cancer cells. More recently, researchers have identified another challenge: surgery itself weakens the immune system temporarily, making it easier for the cancer to come back.

Now, a research team at The Ottawa Hospital has discovered a promising approach to strengthen the immune system around the time of surgery and prevent cancer from coming back in mice. 

Led by Dr. Rebecca Auer, the team studied the immune cells of 55 patients undergoing cancer surgery. Using advanced techniques, they identified that a molecular switch called PI3K-gamma plays a central role in cancer recurrence after surgery. 

After testing 147 different drug candidates, they found a small number that could completely block the immune-suppressing effect of surgery and restore a normal strength immune system in mice. When tested in mouse models of cancer, the drug candidates were able to greatly reduce cancer recurrence after surgery. 

"In many cases, surgery offers the best chance of a cancer cure,” said Dr. Rebecca Auer, surgical oncologist and senior clinician scientist at The Ottawa Hospital and professor at the University of Ottawa. “By studying the immune system around the time of cancer surgery and developing novel immune-based therapies, we hope to increase the cure rate even further.”

The results are published in the Journal for ImmunoTherapy of Cancer.