Association Between Health-Related Quality of Life and Progression-Free Survival in Patients With Advanced Cancer: A Secondary Analysis of SWOG Clinical Trials

Abstract

PURPOSE Health-related quality of life (HRQOL) is an established prognostic factor for mortality; however, it is unclear if HRQOL is predictive of time to disease progression, a particularly meaningful outcome for patients. We examined the association between HRQOL and progression-free survival (PFS) in SWOG Cancer Research Network clinical trials. METHODS For this secondary analysis, we reviewed all completed SWOG clinical trials to identify those for patients with advanced cancer that incorporated Functional Assessment of Cancer Therapy (FACT) questionnaires at baseline. FACT-Trial Outcome Index (FACT-TOI) was the primary independent variable. Associations between FACT-TOI and other FACT subscores with PFS and overall survival were evaluated via log-rank test and multivariable Cox regression analysis. RESULTS Three clinical trials met our inclusion criteria: S0027 and S9509 for advanced non–small-cell lung cancer and S0421 for hormone-refractory prostate cancer. Of the 1,527 enrolled patients, 1,295 (85%) had both HRQOL and survival outcomes data available and were included in this analysis. In univariable analysis, we observed a statistically significant gradient effect in all three trials, with higher baseline FACT-TOI scores corresponding to better PFS (S0027, P < .001; S9509, P = .02; and S0421, P < .001). In multivariable analysis, FACT-TOI was significantly associated with PFS in S0027 (hazard ratio [HR] = 0.64; 95% CI, 0.42 to 1.00) but not in S9509 (HR = 0.77; 95% CI, 0.56 to 1.05) or S042 (HR = 0.86; 95% CI, 0.73 to 1.01). FACT-TOI was significantly associated with overall survival in multivariable analysis ( P < .005 in all three trials). CONCLUSION The association between baseline FACT-TOI scores and survival underscores their potential as a stratification factor in clinical trials.