Impact of Radiation Therapy Dose Escalation on Prostate Cancer Outcomes and Toxicities

Freedom from biochemical failure (FFBF) is a common primary outcome of randomized-controlled trials of prostate cancer (PCa). We aimed to determine how increasing the PCa biologically equivalent dose (BED) of external radiation therapy (RT) is correlated with FFBF and overall patient outcomes: overall survival (OS), distant metastasis (DM), and cancer-specific mortality (CSM); as well as genitourinary (GU), and gastrointestinal toxicities. We performed a meta-analysis of 6884 PCa patients from 12 randomized-controlled trials of external beam RT. Mixed effects regression models were used to estimate weighted linear relationships between BED and observed percentages of 5- and 10-year outcomes. For toxicities, a subset analysis of using 3-dimensional conformal RT (3D-CRT) versus intensity-modulated RT (IMRT) was performed. Increasing BED correlated with improved FFBF: 10-year absolute improvement of 9.6% and 7.2% for low-risk and intermediate-risk patients, respectively (P