A novel urethral sparing technique for high-dose-rate prostate brachytherapy after transurethral resection of the prostate

Hiroaki Kunogi; Jason Adam M Cunha; Albert J Chang; Adam J Gadzinski; Katsuto Shinohara; I-Chow Hsu

doi:10.1016/j.brachy.2017.07.017

A novel urethral sparing technique for high-dose-rate prostate brachytherapy after transurethral resection of the prostate

Brachytherapy. 2017 Nov-Dec;16(6):1113-1118. doi: 10.1016/j.brachy.2017.07.017. Epub 2017 Aug 30.

Authors

Hiroaki Kunogi¹, Jason Adam M Cunha², Albert J Chang², Adam J Gadzinski³, Katsuto Shinohara³, I-Chow Hsu⁴

Affiliations

¹ Department of Radiation Oncology, University of California San Francisco, San Francisco, CA; Department of Radiation Oncology, Juntendo University, Hongo, Bunkyo-ku, Tokyo, Japan.
² Department of Radiation Oncology, University of California San Francisco, San Francisco, CA.
³ Department of Urology, University of California San Francisco, San Francisco, CA.
⁴ Department of Radiation Oncology, University of California San Francisco, San Francisco, CA. Electronic address: ihsu@radonc.ucsf.edu.

PMID: 28869143
DOI: 10.1016/j.brachy.2017.07.017

Abstract

Purpose: The purpose of this study was to assess retrospectively the variability of the urethral dose optimized using a Foley catheter versus urethral contrast injected using a new modified triple-lumen catheter, in CT-based high-dose-rate (HDR) prostate brachytherapy of posttransurethral resection of prostate (TURP) patients.

Methods and materials: At our institution, there were six post-TURP patients with prostate carcinoma between July 2014 and April 2016 who underwent transperineal interstitial HDR brachytherapy (16 needles). A custom modified triple-lumen catheter was placed to inject contrast into the TURP defect. Three-dimensional optimal plans using inverse planning simulated annealing algorithm was generated according to radiation therapy oncology group dose requirements. Alternative plans were retroactively generated for comparison using standard technique based on a Foley catheter as a urethral constraint volume for each patient with the same weighting factors. We compared the dosimetry parameters in each planning using Wilcoxon's ranked sum nonparametric test.

Results: The median followup of all patients was 17.5 months. No significant genitourinary or gastrointestinal toxicity was noted using this technique. In the dosimetric analysis, the prostate V₁₀₀ values and TURP urethral V₁₀₀ were significantly different between plans with and without the contrast (V₁₀₀ [mean]: 92.4 [%] vs. 94.4 [%], p = 0.046; TURP UV₁₀₀ [mean]: 1.4 cc vs. 2.2 cc, p = 0.028). There were no statistical differences in the mean values of planning target volume V₁₅₀%, V₂₀₀%, and D₉₀, and each bladder V₇₅ and rectum V₇₅.

Conclusions: Post-TURP HDR brachytherapy with urethral contrast showed significantly more volume effect of the TURP defect than that with a Foley catheter alone. Better visualization of the TURP defect should lead to more accurate urethral sparing administration of HDR brachytherapy which is necessary to prevent urethral complication.

Keywords: Brachytherapy; HDR; Prostate; TURP; Urinary catheter.

MeSH terms

Aged
Algorithms
Brachytherapy / adverse effects
Brachytherapy / methods*
Catheters
Humans
Male
Middle Aged
Organ Sparing Treatments / methods*
Organs at Risk / diagnostic imaging
Organs at Risk / radiation effects
Prostatic Neoplasms / diagnostic imaging
Prostatic Neoplasms / radiotherapy*
Radiation Injuries / prevention & control
Radiometry / methods
Radiotherapy Dosage
Radiotherapy Planning, Computer-Assisted / methods
Rectum / diagnostic imaging
Rectum / radiation effects
Retrospective Studies
Tomography, X-Ray Computed
Transurethral Resection of Prostate*
Urethra / diagnostic imaging
Urethra / radiation effects
Urinary Bladder / diagnostic imaging
Urinary Bladder / radiation effects