Response rate – using RECIST (Response evaluation criteria in solid tumors) criteria in solid tumors – the immediate response that the solid tumors had – did it grow or shrink? This is very short time duration. It is usually from the first time the imaging was done till the next time.
RECIST : categories are progression (20% volume from its original size increase), less than that is stable disease. Complete response – means that there is no evidence of tumor left. Partial response – means a shrinkage of at least 30% in volume). Response rate is not a statistical measure for the number of patients generally.
Survival:
Overall survival: This is the gold standard and should be the primary measurement. This speaks to a lengthening of life. This is in comparison to what patient would usually survive.
Progression free survival – disease free survival: Secondary endpoint that treatment is usually used for studies these days. This speaks to advantage the therapy affords by holding the cancer at bay during the therapy. No growth of the tumor – no progression. The period of time when there is no progression free survival is measured as PFS and sometimes can be correlated with Overall survival but may not impact the total length of life. In some cases – stopping the growth in a local area can be useful.
In JAMA article: https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2782339 for Non small cell lung cancer and colorectal cancer, the Overall survival and progression free survival was correlated.
Another term that is used is event free survival which is time between starting treatment and having an event – which could be a specific symptom, a pain or something critical such as a fracture.
Watch these definitions in a video:
