Predictive value of serial measurements of quality of life on all-cause mortality in prostate cancer patients: Data from CaPSURE™ (cancer of the prostate strategic urologic research endeavor) database

Abstract

Introduction: Health-related quality of life (HRQOL) is a legitimate construct for evaluating treatment and its side effects. Recently, predictive value of HRQOL on survival also has been of interest. In light of the longer survival in patients with prostate cancer and importance of quality of life, we seek to evaluate the association between HRQOL and survival using traditional and novel techniques. Methods: Patients from CaPSURE (Cancer of the Prostate Strategic Urologic Research Endeavor) who were treated within 6 months of diagnosis and had pre-treatment and sufficient post-treatment follow-up information constituted the study population. A sample consisting of 2,899 patients met the study criteria. SF-36 domains were used to measure HRQOL outcomes. Categorical variables were created for HRQOL based on the baseline distribution of the lower 10th percentile and the remainder of the patients. Association between HRQOL and survival (defined by all-cause mortality) in patients with prostate cancer was evaluated using Cox proportional hazards models controlling for age at diagnosis, type of treatment received, clinical risk classification, and number of comorbidities. Sequential bootstrap resampling was implemented to evaluate stability of the model. Univariate and multivariate Cox proportional hazards models were fit using various time points over the course of follow-up. Results: In the analysis looking at association of HRQOL baseline measurements, higher levels of physical function and general health were significantly associated with better survival (HR 0.49 95% CI 0.32-0.78 and HR 0.51 95% CI 0.35-0.75, respectively). Post-treatment analysis demonstrated similar results. In time-dependent analysis, higher levels of physical function, role physical, and general health were significantly associated with better survival (HR ranged from 0.57 to 0.65). In addition, analysis looking at change in HRQOL scores demonstrated an association between higher scores on physical function, role physical, vitality, social function, and general health and longer survival (HR ranged from 0.56 to 0.63). Conclusion: This study demonstrated that several domains of HRQOL were significantly associated with survival in a large group of patients with localized prostate cancer. This association was maintained over the course of disease regardless of the time of the assessment. Results from our study have both research and clinical relevance. They could provide information that enable us to not only improve communication with patients and families, but also to develop interventions and treatments best suited for the patient.