Progression-free survival is a poor surrogate for overall survival and should not be relied upon as a primary endpoint for registration and marketing of anticancer drugs, according to Canadian oncologists.

The use of progression-free survival (PFS) remains debated despite being the most common primary endpoint in oncology trials, the research team led by Queen’s University in Ontario said.

But they argued PFS — time from randomisation or treatment initiation to occurrence of disease progression or death — was “misleading” and confusing for patients.

“Blanket acceptance of PFS as a primary endpoint for full registration of new drugs in cancer has led to clinical use of therapies that produce no significant improvement in OS [overall survival] or QoL [quality of life],” they wrote in the Journal of Clinical Oncology.