Progression-Free Survival Methodology Flawed
May lead to overestimates
FRIDAY, March 23 (HealthDay News) -- The methodology used to determine progression-free survival, which is increasingly used as a primary endpoint in cancer clinical trials, often leads to overestimates, according to a study in the March 21 issue of the Journal of the National Cancer Institute.
Katherine S. Panageas, Dr.P.H., and colleagues from Memorial Sloan-Kettering Cancer Center in New York City, examined the use of progression-free survival as a clinical endpoint in published studies and through a simulation study.
The researchers note that the time of disease progression is typically recorded at the radiologic assessment when progression is detected even though the progression would have occurred earlier, which can lead to "interval-censored data" and overestimation of progression-free survival. "This overestimation can erroneously result in a result being described as clinically significant when in fact a longer median progression-free survival may just be a consequence of the length of the surveillance interval," they write.
"The decision to use progression-free survival as a primary endpoint should be made carefully when designing clinical trials, and investigators focused on a particular disease should develop consensus standards and strive for consistent surveillance intervals," Panageas and colleagues conclude.