progression-free survival

Definition of progression-free survival
National Cancer Institute

progression-free survival

(pruh-GREH-shun ... ser-VY-vul)
The length of time during and after the treatment of a disease, such as cancer, that a patient lives with the disease but it does not get worse. In a clinical trial, measuring the progression-free survival is one way to see how well a new treatment works. Also called PFS.

Source: NCI Dictionary of Cancer Terms