No abstract

Background Targeted magnetic resonance (MR)/ultrasound fusion prostate biopsy (MRI-Bx) has recently been compared to standard of care extended sextant ultrasound-guided prostate biopsy (SOC-Bx) and was associated with an increased rate of detection of clinically significant prostate cancer. This study sought to determine the influence of MRI-Bx on radiation and androgen deprivation therapy (ADT) treatment recommendations. Methods/Materials All patients treated with radiotherapy that underwent SOC-Bx and MRI-Bx at our institution were included. Using clinical T stage, pretreatment PSA, and Gleason score, patients were categorized into NCCN risk groups and radiation/ADT treatment recommendations were assigned. Intensification of recommended treatment after multiparametric MRI, SOC-Bx, and MRI-Bx was evaluated. Results From January 2008 to January 2016, 73 patients received radiation therapy at our institution after undergoing a simultaneous SOC-Bx and MRI-Bx (n=47 with prior SOC-Bx). Repeat SOC-Bx and MRI-Bx resulted in frequent upgrading compared to prior SOC-Bx (Gleason 7: 6.7% vs. 44.6%, p<0.001; Gleason 8–10: 2.1% vs. 38%, p<0.001). MRI-Bx increased the proportion of patients classified as very-high risk from 24.7% to 41.1% (p=0.027). Compared to SOC-Bx alone, including MRI-Bx findings resulted in a higher percentage of pathologically positive cores (mean 37% vs. 44%). Incorporation of multiparametric MRI and MRI-Bx results increased the recommended use and duration of ADT (duration increased in 28/73 patients, addition in 8/73 patients). Conclusion In patients referred for radiotherapy, MRI-Bx resulted in an increase in the percentage of positive cores, Gleason Score, and risk grouping. The benefit of treatment intensification based on MRI-Bx findings is unknown.