title: Results of multiparametric transrectal ultrasound-based focal high-dose-rate dose escalation combined with supplementary external beam irradiation in intermediate- and high-risk localized prostate cancer patients.
abstract: OBJECTIVE
  Clinical results of a biologic information-based focused dose escalation combined with dose de-escalation for the whole organ in external beam radiotherapy + high-dose-rate brachytherapy (HDR-BT) boost application for localized prostate cancer in a consecutively treated patient cohort.
  
  
  METHODS
  One hundred thirty patients were treated with external beam radiotherapy (50 Gy) complementary to two multiparametric transrectal ultrasound-guided 15 Gy HDR-BT fractions. Real-time multiparametric transrectal ultrasound-based biologic planning for high-dose-rate boost dose planning used the summation of gray scale and Doppler sonography imaging + biopsy information. Target subvolumes received HDR-BT dose escalation up to 60 Gy/fraction. Dose-volume histogram parameters, organ at risks doses, and toxicity results were investigated.
  
  
  RESULTS
  The median followup was 4.3 years, the median age was 68.62 years, and the mean initial prostate-specific antigen was 18.69 ng/mL. Low-, intermediate-, and high-risk constituted 69%, 21%, and 10% of the patients, respectively. The mean peripheral dose was 3.9 Gy per fraction. Prostate-specific antigen nadir was in 93% of the patients ≤1 ng/mL. Quality parameters were as follows: D90: 6.58 Gy, V100: 30.36%, V150: 9.96%, V200: 3.16%, uD0.1: 7.34 Gy, uD2: 9.34 Gy, rD01: 10.56 Gy, and rD2: 8.32 Gy, respectively. We observed G1, G2, G3 urinary toxicity in 17/130, 11/130, and 2/130 patients, respectively. Rectal toxicity: G1 and G2 occurred in 19/130 and 2/130 patients with mean dose values G1: 8.2 Gy and G2: 8.76 Gy. Analysis of variance test resulted in no correlation between toxicities and any other investigated factors.
  
  
  CONCLUSIONS
  Focused extreme dose escalation with low prostate mean peripheral dose results in excellent long-term outcome data and very high focal boost doses and is causing no enhancement in late treatment toxicity.
authors.affiliation: Interdisciplinary Brachytherapy Unit, University of Lübeck/UKSH-CL, Germany. Electronic address: kovacsluebeck@gmail.com.
authors.forename: György
authors.initials: G
authors.lastname: Kovács
authors.affiliation: Interdisciplinary Brachytherapy Unit, University of Lübeck/UKSH-CL, Germany.
authors.forename: Klaudia
authors.initials: K
authors.lastname: Müller
authors.affiliation: Interdisciplinary Brachytherapy Unit, University of Lübeck/UKSH-CL, Germany; Radiation Oncology Department, National Cancer Institute (NCI), Cairo University, Egypt.
authors.forename: Tamer
authors.initials: T
authors.lastname: Soror
authors.affiliation: Interdisciplinary Brachytherapy Unit, University of Lübeck/UKSH-CL, Germany.
authors.forename: Corinna
authors.initials: C
authors.lastname: Melchert
authors.affiliation: Clinic of Urology, University of Lübeck/UKSH-CL, Germany.
authors.forename: Xiyuan
authors.initials: X
authors.lastname: Guo
authors.affiliation: Clinic of Urology, University of Lübeck/UKSH-CL, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Jocham
authors.affiliation: Clinic of Urology, University of Lübeck/UKSH-CL, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Merseburger
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects / Q000379:methods*; D019583:Dose Fractionation, Radiation; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000209:etiology; D011879:Radiotherapy Dosage; D012002:Rectal Diseases / Q000209:etiology; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional / Q000379:methods*; D014570:Urologic Diseases / Q000209:etiology
chemical_list: D017430:Prostate-Specific Antigen
keywords: Biologic planning; Focal therapy; HDR brachytherapy; Multiparametric TRUS; Prostate cancer