Prostate Specific Antigen (PSA) as Predicting Marker for Clinical Outcome and Evaluation of Early Toxicity Rate after High-Dose Rate Brachytherapy (HDR-BT) in Combination with Additional External Beam Radiation Therapy (EBRT) for High Risk Prostate Cancer

High-dose-rate brachytherapy (HDR-BT) with external beam radiation therapy (EBRT) is a common treatment option for locally advanced prostate cancer (PCa). Seventy-nine male patients (median age 71 years, range 50 to 79) with high-risk PCa underwent HDR-BT following EBRT between December 2009 and January 2016 with a median follow-up of 21 months. HDR-BT was administered in two treatment sessions (one week interval) with 9 Gy per fraction using a planning system and the Ir192 treatment unit GammaMed Plus iX. EBRT was performed with CT-based 3D-conformal treatment planning with a total dose administration of 50.4 Gy with 1.8 Gy per fraction and five fractions per week. Follow-up for all patients was organized one, three, and five years after radiation therapy to evaluate early and late toxicity side effects, metastases, local recurrence, and prostate-specific antigen (PSA) value measured in ng/mL. The evaluated data included age, PSA at time of diagnosis, PSA density, BMI (body mass index), Gleason score, D'Amico risk classification for PCa, digital rectal examination (DRE), PSA value after one/three/five year(s) follow-up (FU), time of follow-up, TNM classification, prostate volume, and early toxicity rates. Early toxicity rates were 8.86% for gastrointestinal, and 6.33% for genitourinary side effects. Of all treated patients, 84.81% had no side effects. All reported complications in early toxicity were grade 1. PSA density at time of diagnosis (p = 0.009), PSA on date of first HDR-BT (p = 0.033), and PSA on date of first follow-up after one year (p = 0.025) have statistical significance on a higher risk to get a local recurrence during follow-up. HDR-BT in combination with additional EBRT in the presented design for high-risk PCa results in high biochemical control rates with minimal side-effects. PSA is a negative predictive biomarker for local recurrence during follow-up. A longer follow-up is needed to assess long-term outcome and toxicities.

International journal of molecular sciences. 2016 Nov 10*** epublish ***

Thorsten H Ecke, Hui-Juan Huang-Tiel, Klaus Golka, Silvia Selinski, Berit Christine Geis, Stephan Koswig, Katrin Bathe, Steffen Hallmann, Holger Gerullis

Department of Urology, HELIOS Hospital, D-15526 Bad Saarow, Germany. ., Department of Neurology/Emergency Unit, Vivantes Hospital Spandau, D-13585 Berlin, Germany. ., Leibniz Research Centre for Working Environment and Human Factors IfADo, D-44139 Dortmund, Germany. ., Leibniz Research Centre for Working Environment and Human Factors IfADo, D-44139 Dortmund, Germany. ., Leibniz Research Centre for Working Environment and Human Factors IfADo, D-44139 Dortmund, Germany. ., Department of Radio-Oncology, HELIOS Hospital, D-15525 Bad Saarow, Germany. ., Department of Radio-Oncology, HELIOS Hospital, D-15525 Bad Saarow, Germany. ., Department of Urology, HELIOS Hospital, D-15526 Bad Saarow, Germany. ., School of Medicine and Health Sciences Carl von Ossietzky, University Oldenburg, D-26133 Oldenburg, Germany. .