1. EFS：Event-free survival refers to the percentage of patients who remain free from a specified event, such as a recurrence or progression of the disease, within a certain period of time following a treatment.

2. PFS: Progression-free survival is a measure of the time elapsed between treatments for a disease, such as cancer, and the occurrence of disease progression or the start of a new treatment.

3. DFS: Disease-free survival is the length of time a patient lives without the return of their disease after treatment. It is often used in cancer research and treatment to measure the effectiveness of a treatment.

4. FFS: Failure-free survival is a term used to describe the period of time during which a product, system, or service operates without failure. It is a measure of reliability and is often used in engineering and quality assurance.