Impact of magnetic resonance imaging (MRI) in the local staging, risk group classification, and treatment of patients with prostate cancer with combination of high dose rate (HDR) brachytherapy and external beam radiotherapy (EBRT).

Abstract

202 Background: To assess the impact of magnetic resonance imaging (MRI) staging for patients undergoing High Dose Rate (HDR) brachytherapy with external beam radiotherapy (EBRT). Methods: Fifty consecutive patients with intermediate risk and high risk prostate cancer underwent staging MRI. The MRI findings were used to guide stage-appropriate treatment recommendations, and to assist in the preplanning and optimization of the brachytherapy isodose distributions. Results: Median age of the patients was 71 years (range 58-78), median pre-treatment PSA was 10.15 ng/ml (3.3-66), median prostate volume was 35cc (14-58). Eighty-four percent of the patients were Gleason ≥ 7. Fifty-two percent had ≥ 50 of cores involved. Fifty four percent of patient’s PSA was ≥ 10 ng/ml. Pre-MRI staging was T1 in 70% of the patients, T2 in 30 %. Of the 50 patients staged by MRI, 70% were upstaged from the digital rectal examination-based clinical stage; 46% of cT1- T2 patients were upstaged to cT3. This upstaging changed the risk group in 56% of the patients while using the NCCN classification and in 24% when the D’Amico classification was used. The treatment reccomendation was modified in 26% and 20% of the patients using the NCCN and the D’Amico classification respectively. Conclusions: Staging MRI impacts in the assessment of the local staging, leading to changes in risk group classification and treatment decision in intermediate and high risk patients undergoing HDR brachytherapy and EBRT.