title: High-dose-rate brachytherapy delivered in two fractions as monotherapy for low-risk prostate cancer.
abstract: OBJECTIVE
  High-dose-rate (HDR) brachytherapy has been accepted as an effective and safe method to treat prostate cancer. The aim of this study was to describe acute toxicity following HDR brachytherapy to the prostate, and to examine the association between dosimetric parameters and urinary toxicity in low-risk prostate cancer patients.
  
  
  METHODS
  Patients with low-risk prostate cancer were given HDR brachytherapy as monotherapy in two 12.5 Gy fractions. Planning objectives for the planning target volume (PTV) were V100% ≥ 90% and V150% ≤ 35%. Planning objectives for organs at risk were V75% ≤ 1 cc for the bladder, rectum and perineum, and V125% ≤ 1 cc for the urethra. Toxicity was assessed three months after treatment using the Common Terminology Criteria for Adverse Events.
  
  
  RESULTS
  Seventy-three patients were included in the analysis. Thirty-three patients (45%) reported having any type of toxicity in the three months following HDR brachytherapy. Most toxicity cases (26%) were grade 1 urinary toxicity. Mean coverage index was 0.89 and mean V100 was 88.85. Doses administered to the urethra were associated with urinary toxicity. Patients who received more than 111.3% of the prescribed dose in 1 cc of the urethra were four times more likely to have urinary toxicity compared to patients receiving less than 111.3% (OR = 4.71, 95% CI: 1.43-15.6; p = 0.011).
  
  
  CONCLUSIONS
  High-dose-rate brachytherapy administered as monotherapy for prostate cancer proved to be a safe alternative treatment for patients with low-risk prostate cancer. Urinary toxicity was associated with the dose administered to 1 cc and 0.1 cc of the urethra and was remarkably inferior to the reported toxicity in similar studies.
authors.affiliation: Centro de Control de Cancer Ltda., Bogota, Colombia.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Cendales
authors.affiliation: Centro de Control de Cancer Ltda., Bogota, Colombia.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Alwers
authors.affiliation: Centro de Control de Cancer Ltda., Bogota, Colombia.
authors.forename: Javier
authors.initials: J
authors.lastname: Cifuentes
authors.affiliation: Centro de Control de Cancer Ltda., Bogota, Colombia.
authors.forename: Ivan
authors.initials: I
authors.lastname: Bobadilla
authors.affiliation: Centro de Control de Cancer Ltda., Bogota, Colombia.
authors.forename: Felipe
authors.initials: F
authors.lastname: Torres
authors.affiliation: Centro de Control de Cancer Ltda., Bogota, Colombia.
authors.forename: Juan
authors.initials: J
authors.lastname: Arbelaez
authors.affiliation: Centro de Control de Cancer Ltda., Bogota, Colombia.
authors.forename: Armando
authors.initials: A
authors.lastname: Gaitan
authors.affiliation: Centro de Control de Cancer Ltda., Bogota, Colombia.
authors.forename: Helber
authors.initials: H
authors.lastname: Cortes
authors.affiliation: Centro de Control de Cancer Ltda., Bogota, Colombia.
authors.forename: Yenny
authors.initials: Y
authors.lastname: Acevedo
authors.affiliation: Centro de Control de Cancer Ltda., Bogota, Colombia.
authors.forename: Paulo
authors.initials: P
authors.lastname: Quintero
authors.affiliation: Centro de Control de Cancer Ltda., Bogota, Colombia.
authors.forename: Jaider
authors.initials: J
authors.lastname: Vasquez
keywords: acute toxicity; high-dose-rate brachytherapy; monotherapy; prostate cancer
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