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

György Kovács; Klaudia Müller; Tamer Soror; Corinna Melchert; Xiyuan Guo; Dieter Jocham; Axel Merseburger

doi:10.1016/j.brachy.2016.11.005

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

Brachytherapy. 2017 Mar-Apr;16(2):277-281. doi: 10.1016/j.brachy.2016.11.005. Epub 2016 Dec 7.

Authors

György Kovács¹, Klaudia Müller², Tamer Soror³, Corinna Melchert², Xiyuan Guo⁴, Dieter Jocham⁴, Axel Merseburger⁴

Affiliations

¹ Interdisciplinary Brachytherapy Unit, University of Lübeck/UKSH-CL, Germany. Electronic address: kovacsluebeck@gmail.com.
² Interdisciplinary Brachytherapy Unit, University of Lübeck/UKSH-CL, Germany.
³ Interdisciplinary Brachytherapy Unit, University of Lübeck/UKSH-CL, Germany; Radiation Oncology Department, National Cancer Institute (NCI), Cairo University, Egypt.
⁴ Clinic of Urology, University of Lübeck/UKSH-CL, Germany.

PMID: 27964906
DOI: 10.1016/j.brachy.2016.11.005

Abstract

Purpose: 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 and materials: 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%, uD_0.1: 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.

Keywords: Biologic planning; Focal therapy; HDR brachytherapy; Multiparametric TRUS; Prostate cancer.

MeSH terms

Aged
Aged, 80 and over
Brachytherapy / adverse effects
Brachytherapy / methods*
Dose Fractionation, Radiation
Follow-Up Studies
Humans
Male
Middle Aged
Prostate-Specific Antigen / blood
Prostatic Neoplasms / diagnostic imaging
Prostatic Neoplasms / pathology
Prostatic Neoplasms / radiotherapy*
Radiation Injuries / etiology
Radiotherapy Dosage
Rectal Diseases / etiology
Treatment Outcome
Ultrasonography, Interventional / methods*
Urologic Diseases / etiology

Substances

Prostate-Specific Antigen