Identification of Potential Surrogate Endpoints of Long-Term Survival in Prostate Cancer
Lack of general treatment failure or distant metastases 3 years after the start of treatment may be surrogate endpoints for long-term survival in patients with early prostate cancer.
Prostate cancer is a slowly progressing malignancy in many patients. The long natural history of the disease makes evaluation of new therapies difficult because patients must be followed for many years. If researchers could identify a surrogate clinical endpoint that accurately reflects long-term clinical outcomes for prostate cancer, clinical trials would be easier and faster.
To look for possible surrogate endpoints, Michael E. Ray, M.D., Ph.D., of ThedaCare and Bellin Health Systems in Appleton and Green Bay, Wisconsin, and colleagues evaluated the ability of general treatment failure and metastasis-free survival at 3 and 5 years to predict long-term survival in patients who had taken part in a clinical trial. A total of 1,521 patients who participated in the Radiation Therapy and Oncology Group 92-02 randomized controlled trial were included in the current analysis.
The authors found that both distant metastasis and general clinical treatment failure at 3 years were consistent with the four statistical criteria developed by Prentice for surrogate endpoints. At 5 years, only three of the four criteria were potentially fulfilled because prostate-cancer specific survival was not statistically significantly different between the two trial arms.
"The potential surrogate endpoints, distant metastasis and general clinical treatment failure, should be further and prospectively evaluated in future clinical trials along with overall and prostate cancer-specific survival endpoints," the authors conclude.
In an accompanying editorial, Ross L. Prentice, Ph.D., of the Fred Hutchinson Cancer Research Center in Seattle, who developed Prentice's c
|Contact: Caroline McNeil|
Journal of the National Cancer Institute