title: Urethrogram-Directed Stereotactic Body Radiation Therapy for Clinically Localized Prostate Cancer in Patients with Contraindications to Magnetic Resonance Imaging.
abstract: OBJECTIVE
  Magnetic resonance imaging (MRI)-directed stereotactic body radiation therapy (SBRT) has been established as a safe and effective treatment for prostate cancer. For patients with contraindications to MRI, CT-urethrogram is an alternative imaging approach to identify the location of the prostatic apex to guide treatment. This study sought to evaluate the safety of urethrogram-directed SBRT for prostate cancer.
  
  
  METHODS
  Between February 2009 and January 2014, 31 men with clinically localized prostate cancer were treated definitively with urethrogram-directed SBRT with or without supplemental intensity-modulated radiation therapy (IMRT) at Georgetown University Hospital. SBRT was delivered either as a primary treatment of 35-36.25 Gy in five fractions or as a boost of 19.5 Gy in three fractions followed by supplemental conventionally fractionated IMRT (45-50.4 Gy). Toxicities were recorded and scored using the Common Terminology Criteria for Adverse Events version 4.0 (CTCAE v.4.0).
  
  
  RESULTS
  The median patient age was 70 years with a median prostate volume of 38 cc. The median follow-up was 3.7 years. The patients were elderly (Median age = 70), and comorbidities were common (Carlson comorbidity index ≥2 in 36%). Seventy-one percent of patients utilized alpha agonists prior to treatment, and 9.7% had prior procedures for benign prostatic hyperplasia. The 3-year actuarial incidence rates of ≥Grade 3 GU toxicity and ≥Grade 2 GI toxicity were 3.2 and 9.7%, respectively, and there were no Grade 4 or 5 toxicities.
  
  
  CONCLUSIONS
  Magnetic resonance imaging is the preferred imaging modality to guide prostate SBRT treatment. However, urethrogram-directed SBRT is a safe alternative for the treatment of patients with prostate cancer who are unable to undergo MRI.
authors.affiliation: Department of Radiation Medicine, Georgetown University Hospital , Washington, DC , USA.
authors.forename: Ima
authors.initials: I
authors.lastname: Paydar
authors.affiliation: Department of Radiation Medicine, Georgetown University Hospital , Washington, DC , USA.
authors.forename: Brian S
authors.initials: BS
authors.lastname: Kim
authors.affiliation: Department of Radiation Medicine, Georgetown University Hospital , Washington, DC , USA.
authors.forename: Robyn A
authors.initials: RA
authors.lastname: Cyr
authors.affiliation: Department of Radiation Medicine, Georgetown University Hospital , Washington, DC , USA.
authors.forename: Harriss
authors.initials: H
authors.lastname: Rashid
authors.affiliation: Department of Radiation Medicine, Georgetown University Hospital , Washington, DC , USA.
authors.forename: Amna
authors.initials: A
authors.lastname: Anjum
authors.affiliation: Department of Radiation Medicine, Georgetown University Hospital , Washington, DC , USA.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Yung
authors.affiliation: Department of Radiation Medicine, Georgetown University Hospital , Washington, DC , USA.
authors.forename: Siyuan
authors.initials: S
authors.lastname: Lei
authors.affiliation: Department of Radiation Medicine, Georgetown University Hospital , Washington, DC , USA.
authors.forename: Brian T
authors.initials: BT
authors.lastname: Collins
authors.affiliation: Department of Radiation Medicine, Georgetown University Hospital , Washington, DC , USA.
authors.forename: Simeng
authors.initials: S
authors.lastname: Suy
authors.affiliation: Department of Radiation Medicine, Georgetown University Hospital , Washington, DC , USA.
authors.forename: Anatoly
authors.initials: A
authors.lastname: Dritschilo
authors.affiliation: Department of Urology, Georgetown University Hospital , Washington, DC , USA.
authors.forename: John H
authors.initials: JH
authors.lastname: Lynch
authors.affiliation: Department of Radiation Medicine, Georgetown University Hospital , Washington, DC , USA.
authors.forename: Sean P
authors.initials: SP
authors.lastname: Collins
keywords: CyberKnife; SBRT; magnetic resonance imaging; prostate cancer; urethrogram