Although living without disease progression is clearly a good thing, in the ongoing debate over the use of progression-free survival (PFS) as a formal endpoint in clinical trials, one frequent concern is how does PFS relate to overall survival (OS) or extension of life. As a follow-up to our earlier post, we thought you might be interested in seeing what some of the experts have to say. The following link will take you to a summary of a paper published in late 2009 in the Journal of the National Cancer Institute in which leading statisticians analyze the relationship between PFS and OS in the context of how long a person is likely to survive after disease progression, something that varies substantially among different cancer types and stages.
Although there are many aspects to consider in the PFS versus OS debate, one of our concerns is that by discounting a significant increase in PFS when it is not acccompanied by a statistically significant increase in OS, we might be rushing to judgement and missing important clinical benefits for some patients provided by a treatment that does not work for every patient.
Clearly, better tools are needed to predict which patients will benefit and which will not benefit from any given treatment (and importantly, which will be harmed), but that is a topic for another post. . .