The changing landscape of systemic therapy in the treatment of synchronous metastatic hormone-sensitive prostate cancer

To describe the changes in systemic treatments (ST) of synchronous metastatic hormone-sensitive prostate cancer (mHSPC) patients in a "real-world" setting and to explore reasons why contemporary standard of care (SOC) was not administrated to the patient.Since 2014, we prospectively register mHSPCpatients. Patients were grouped in 4 time periods: group 1 (Time period 1, January 2014-July 2015), group 2 after introduction of docetaxel (Time period 2, August 2015-July 2017), group 3 after introduction of abiraterone acetate (Time period 3, August 2017-February 2018) and group 4 after introduction of apalutamide (Time period 4, March 2018-October 2021). For every time period, we evaluated the initiated additional ST. In case patients received treatment that differed from contemporary SOC according to guidelines, reasons for this difference were explored.In total, 243 patients were included. A progressive decline in ADT monotherapy from 85% to 29% over time was observed. The proportion of patients receiving additional STs increased from 34% to 59%. Forty percent of patients were not treated according to contemporary SOC, but this percentage varied strongly per time period (10%, 67%, 53%, and 32% from time period 1 to time period 4 respectively). Reasons for these variations were heterogenous and varied across the 4 time periods. Patients being unfit for treatment and treating physicians failing to consider additional STs were the most prevalent reasons. The proportion of patients unfit for additional ST decreased from 18% to 4% over time.Use of ADT monotherapy declined gradually after the introduction of additional systemic treatments. The proportion of patients unfit for additional ST declined as more treatments became available. Although compliance to SOC increased over time, these real-world data show that adherence to clinical practice guidelines remains suboptimal. Efforts should be made by clinicians to increase the adherence to practice guidelines.