Survival Trend in Individuals With De Novo Metastatic Prostate Cancer After the Introduction of Doublet Therapy

IMPORTANCE: Recently, life-prolonging treatments for patients with advanced prostate cancer have been introduced in clinical practice. OBJECTIVE: To investigate if the introduction of doublet therapy is associated with changes in survival on a population-basis. DESIGN, SETTING, AND PARTICIPANTS: This nationwide population-based cohort study used data from the Prostate Cancer data Base Sweden from 2008 to 2020. Men registered with de novo metastatic castration-sensitive prostate cancer (mCSPC) were included. EXPOSURE: The proportion of men with mCSPC who received doublet therapy, ie, androgen deprivation therapy plus androgen receptor pathway inhibitor drugs or chemotherapy was assessed. MAIN OUTCOMES AND MEASURES: Standardized overall survival, taking age, comorbidity, and cancer characteristics into consideration, was estimated by use of a parametric survival model. RESULTS: A total of 11 382 men were included in this study (median [IQR] age, 74.0 [68-81] years). There was a shift toward less advanced prostate cancer during the study period with a decrease in median (IQR) prostate-specific antigen at diagnosis in men with mCSPC from 145 (39-571) ng/mL to 107 (27-426) ng/mL. Upfront treatment with doublet therapy in these men simultaneously increased from 1% (7 of 991) in 2016 to 44% (402 of 922) in 2020. The adjusted 5-year overall survival increased from 26% (95% CI, 25%-28%) from 2008 to 2012 to 35% (95% CI, 31%-40%) from 2017 to 2020. During the first 5 years after diagnosis, there was an increase in mean survival of 6 months, from 2.7 (95% CI, 2.6-2.8) years from 2008 to 2012 to 3.2 (95% CI, 3.1-3.1) years from 2017 to 2020. CONCLUSIONS AND RELEVANCE: In parallel with improvements in treatment of advanced prostate cancer, a clinically meaningful increase in mean survival was observed in men with de novo mCSPC in Sweden between 2008 and 2020 in this study.