progression free survival and overall survival

Hi Joellen,

I am sure others with more knowledge than I have will chime in but I'll give it a whirl. Progression free survival is usually reported as the median time before the cancer progresses whereas overall survival is the median time until death. I recently read that while Ibrance doubled the progression free period it had no impact on overall survival and must admit that I also did a bit of a double take. Huh? But I think what we need to keep in mind is that the stats are based on the entire population in the study and not individuals. It does not mean that, in your case, your life has not been extended through the use of the drugs. I also believe that it is a bit early for the researchers to report on overall survival as, in theory, in order to be accurate, 100% of the patients would need to be deceased. We know that is not the case. Finally, I have typically seen these stats reported against another drug or combination, not in the absence of treatment. (I believe the stat for Ibrance was stated as Ibrance/Femara or Femara alone.)

Hopefully Bestbird will comment. She's a whiz at this stuff.

Here's how I thought it worked. Let's say we have a stage 3er on these meds and they work for 4 yrs before the person has progression to stage 4, then they pass a year later. We also have a stage 4er on these meds, which work well for 4 yrs, then stop working and they pass a year later. The overall survival is the same (5yrs) but I think "progression" is only considered in the earlier stage since those of us dxd as stage IV basically had our progression from the beginning. I might be totally wrong though.

Survival statistics for treatments compare different treatments and not survival without treatment.  Hypothetically, if too many people are dying of other non-bc causes while on one drug, overall survival statistics from another drug may be higher even if progression-free survival is lower.  Hypothetically, if you have progression on one drug and move on to another which allows you to be NED or stable again for a long time, and there are enough people doing the same, the overall survival statistics taking into account only a single line of treatment is no longer as meaningful.

These issues and more are discussed here:

http://ascopubs.org/doi/full/10.1200/JCO.2011.38.6359

PFS may be an attractive end point because it is available earlier than OS, less influenced than OS by competing causes of death, and not influenced by treatments administered after progression.