title: Polyethylene glycol hydrogel rectal spacer implantation in patients with prostate cancer undergoing combination high-dose-rate brachytherapy and external beam radiotherapy.
abstract: To present rectal toxicity rates in patients administered a polyethylene glycol (PEG) hydrogel rectal spacer in conjunction with combination high-dose-rate brachytherapy and external beam radiotherapy.
  
  
  
  Between February 2010 and April 2015, 326 prostate carcinoma patients underwent combination high-dose-rate brachytherapy of 16 Gy (average dose 15.5 Gy; standard deviation [SD] = 1.6 Gy) and external beam radiotherapy of 59.4 Gy (average dose 60.2 Gy; SD = 2.9 Gy). In conjunction with the radiation therapy regimen, each patient was injected with 10 mL of a PEG hydrogel in the anterior perirectal fat space. The injectable spacer (rectal spacer) creates a gap between the prostate and the rectum. The rectum is displaced from the radiation field, and rectal dose is substantially reduced. The goal is a reduction in rectal radiation toxicity. Clinical efficacy was determined by measuring acute and chronic rectal toxicity using the National Cancer Center Institute Common Terminology Criteria for Adverse Events v4.0 grading scheme.
  
  
  
  Median followup was 16 months. The mean anterior-posterior separation achieved was 1.6 cm (SD = 0.4 cm). Rates of acute Grade 1 and 2 rectal toxicity were 37.4% and 2.8%, respectively. There were no acute Grade 3/4 toxicities. Rates of late Grade 1, 2, and 3 rectal toxicity were 12.7%, 1.4%, and 0.7%, respectively. There were no late Grade 4 toxicities.
  
  
  
  PEG rectal spacer implantation is safe and well tolerated. Acute and chronic rectal toxicities are low despite aggressive dose escalation.
authors: Department of Radiation Oncology, Cancer Center of Irvine, Irvine, CA. Electronic address: jyeh@ccoi.org.
authors: Jekwon
authors: J
authors: Yeh
authors: Department of Radiation Oncology, Cancer Center of Irvine, Irvine, CA.
authors: Brandon
authors: B
authors: Lehrich
authors: Department of Radiation Oncology, Cancer Center of Irvine, Irvine, CA.
authors: Carolyn
authors: C
authors: Tran
authors: Department of Radiation Oncology, Cancer Center of Irvine, Irvine, CA.
authors: Albert
authors: A
authors: Mesa
authors: Department of Radiation Oncology, Cancer Center of Irvine, Irvine, CA.
authors: Ruben
authors: R
authors: Baghdassarian
authors: Department of Radiation Oncology, Cancer Center of Irvine, Irvine, CA.
authors: Jeffrey
authors: J
authors: Yoshida
authors: Department of Radiation Oncology, Cancer Center of Irvine, Irvine, CA.
authors: Robert
authors: R
authors: Torrey
authors: Department of Radiation Oncology, Cancer Center of Irvine, Irvine, CA.
authors: Michael
authors: M
authors: Gazzaniga
authors: Department of Radiation Oncology, Cancer Center of Irvine, Irvine, CA.
authors: Alan
authors: A
authors: Weinberg
authors: Department of Radiation Oncology, Cancer Center of Irvine, Irvine, CA.
authors: Stuart
authors: S
authors: Chalfin
authors: Department of Radiation Oncology, Cancer Center of Irvine, Irvine, CA.
authors: John
authors: J
authors: Ravera
authors: Department of Radiation Oncology, Cancer Center of Irvine, Irvine, CA.
authors: Kenneth
authors: K
authors: Tokita
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000379:methods*; D002277:Carcinoma / Q000532:radiotherapy*; D006801:Humans; D020100:Hydrogels / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D058958:Organs at Risk / Q000528:radiation effects; D011092:Polyethylene Glycols / Q000008:administration & dosage*; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000209:etiology / Q000517:prevention & control*; D011879:Radiotherapy Dosage; D012007:Rectum / Q000528:radiation effects*
chemical_list: D020100:Hydrogels; D011092:Polyethylene Glycols
keywords: Brachytherapy; Cancer; HDR; IMRT; Prostate; Radiation; Rectal; Spacer; Toxicity