abstract: A systematic review evaluating the relationship between progression free survival and post progression survival in advanced ovarian cancer

 Blogger's Note:
this is and has been an ongoing issue in clinical trials as most use still use overall survival (OS) (as per this paper and others)  as the endpoint as opposed to progression free survival; it is a technical debate having wide implications for ovarian cancer treatments/patients, without access to the full text paper and based on the abstract alone,  one outstanding issue would be the impact of QOL/side effects/number of prior treatments, so in plain english as an example - clinical trial x includes standard treatment vs other, no more than eg. 3 prior chemos would be a component of the clinical trial - therefore - what was/is the mix of patients in the trial - all of which impact survival ratios irrespective of PFS/OS; opinions as usual are welcome
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A systematic review evaluating the relationship between progression free survival and post progression survival in advanced ovarian cancer:




Objective 
Although overall survival is the ultimate goal of cancer therapy, many clinical and health economic decisions are taken when only progression free survival (PFS) data are available. This study evaluates the relationship between PFS and post progression survival (i.e. the time between disease progression and death) to estimate how many months a new drug for ovarian cancer might add to overall survival if the number of months the drug added to PFS (relative to a standard drug) was already known.

Methods 
A literature search was conducted over Medline for randomised controlled trials published between January 1990 and July 2010 that evaluated the effect of a drug treatment in comparison to alternative drug treatment in patients with either advanced stage primary or recurrent ovarian cancer.
A systematic review of progression free and post progression survival (PPS) was performed. The relationship between PFS and PPS was evaluated by a graphical method and standard statistical tests.

Results
Thirty-seven trials involving 15,850 patients met the inclusion criteria. The review found that increases in median PFS generally lead to little change in post-progression survival. Percentage gains in PFS are generally associated with no percentage gains or with very slight percentage gains or losses in post-progression survival

Conclusion
If the effect of a new drug treatment for ovarian cancer is to extend median PFS by x months, then it is reasonable to estimate that the treatment will also extend median overall survival by x months. This information will be useful for individual and collective decision making.