Association between progression-free survival and patients' quality of life in cancer clinical trials

Abstract

Quality of life outcomes provide essential information for patients and physicians in oncology care. However, the validity of progression-free survival (PFS) as a surrogate for quality of life, and the inclusion and reporting of quality of life endpoints in clinical trials, is unclear. We performed a retrospective study of phase III clinical trials of drugs for advanced or metastatic solid tumors published between 2010 and 2015. Correlation coefficient (r) and area under the ROC curve (AUC) for association between PFS and positive quality of life were evaluated. Of the 352 Phase 3 trials included, 190 (54%) included a quality of life endpoint, of which 23% did not report pre-specified quality of life outcomes; a total of 125,962 patients were enrolled in studies lacking, or not reporting, quality of life outcomes. Among the 147 trials that reported quality of life outcomes, 99 (67%) reported no effect, 38 (26%) reported a positive effect and 10 (7%) reported a negative effect of treatment on patients' global quality of life. The association between PFS and improvement in global quality of life was weak (r = 0.34; AUC = 0.72), as was the association between PFS and improvement in any domain of quality of life. In conclusion, PFS benefit was not strongly correlated with improvements in patients' quality of life, and, despite the palliative intent of treatments in the advanced/metastatic setting, the availability of quality of life data from clinical trials of cancer drugs was poor.

Keywords: clinical trial; progression-free survival; quality of life; surrogates.