Prognostic association between common laboratory tests and overall survival in men with de novo metastatic castration-sensitive prostate cancer: A population-based study.

149 Background: Despite significant advancements in the treatment of metastatic prostate cancer, a validated prognostic tool for patients with de novo metastatic castration-sensitive prostate cancer (mCSPC) is still lacking. Using population-based data from Ontario, Canada, we sought to examine the prognostic association between common laboratory tests and survival for patients with mCSPC. Methods: A population-based cohort of men aged 66 years and older diagnosed with de novo metastatic prostate cancer between 2014-2019 were included. We assessed the association between laboratory tests at the time of cancer diagnosis and overall survival (OS). Utilizing a complete case analysis, we used Cox proportional hazards models to assess the association between these laboratory tests and OS while adjusting for patient and disease characteristics. Results: A total of 3,556 men with de novo mCSPC were included. On multivariable analysis, there were significant associations between OS and neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, albumin, hemoglobin, PSA decrease and PSA nadir <0.1 ng/mL (please see table). Conclusions: Commonly available laboratory tests provide important prognostic information for patients with newly diagnosed mCSPC given demonstrated associations to overall survival. Apart from PSA kinetics, none of these baseline tests were performed in more than 57% of patients indicating underutilization of these low-cost prognostic biomarkers. [Table: see text]