title: Predictive factors for acute and late urinary toxicity after permanent prostate brachytherapy: long-term outcome in 712 consecutive patients.
abstract: OBJECTIVE
  To describe the frequency of acute and late Radiation Therapy Oncology Group (RTOG) urinary toxicity, associated predictive factors, and resolution of International Prostate Symptom Score (IPSS) in 712 consecutive prostate brachytherapy patients.
  
  
  METHODS
  Patients underwent implantation between 1998 and 2003 (median follow-up, 57 months). The IPSS and RTOG toxicity data were prospectively collected. The patient, treatment, and implant factors were examined for an association with urinary toxicity. The time to IPSS resolution was examined using Kaplan-Meier curves, and multivariate modeling of IPSS resolution was done using Cox proportional hazards regression analysis. Logistic regression analysis was used to examine the factors associated with urinary toxicity.
  
  
  RESULTS
  The IPSS returned to baseline at a median of 12.6 months. On multivariate analysis, patients with a high baseline IPSS had a quicker resolution of their IPSS. Higher prostate D90 (dose covering 90% of the prostate), maximal postimplant IPSS, and urinary retention slowed the IPSS resolution time. The rate of the actuarial 5-year late urinary (>12 months) RTOG Grade 0, 1, 2, 3, and 4 was 32%, 36%, 24%, 6.2%, and 0.1%, respectively. At 7 years, the prevalence of RTOG Grade 0-1 was 92.5%. Patients with a larger prostate volume, greater number of needles, greater baseline IPSS, and use of hormonal therapy had more acute toxicity. On multivariate analysis, the significant predictors for late greater than or equal to RTOG toxicity 2 were a greater baseline IPSS, maximal postimplant IPSS, presence of acute toxicity, and higher prostate V150 (volume of the prostate covered by 150% of the dose). More recently implanted patients had less acute urinary toxicity and patients given hormonal therapy had less late urinary toxicity (all p < 0.02).
  
  
  CONCLUSIONS
  Most urinary symptoms resolved within 12 months after prostate brachytherapy, and significant long-term urinary toxicity was very low. Refined patient selection and greater technical experience in prostate brachytherapy were associated with less urinary toxicity.
authors.affiliation: Vancouver Cancer Center, Vancouver, BC, Canada. mkeyes@bccancer.bc.ca
authors.forename: Mira
authors.initials: M
authors.lastname: Keyes
authors.forename: Stacy
authors.initials: S
authors.lastname: Miller
authors.forename: Veronika
authors.initials: V
authors.lastname: Moravan
authors.forename: Tom
authors.initials: T
authors.lastname: Pickles
authors.forename: Michael
authors.initials: M
authors.lastname: McKenzie
authors.forename: Howard
authors.initials: H
authors.lastname: Pai
authors.forename: Mitchell
authors.initials: M
authors.lastname: Liu
authors.forename: Winkle
authors.initials: W
authors.lastname: Kwan
authors.forename: Alexander
authors.initials: A
authors.lastname: Agranovich
authors.forename: Ingrid
authors.initials: I
authors.lastname: Spadinger
authors.forename: Vincent
authors.initials: V
authors.lastname: Lapointe
authors.forename: Ross
authors.initials: R
authors.lastname: Halperin
authors.forename: W James
authors.initials: WJ
authors.lastname: Morris
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001918:Brachytherapy / Q000009:adverse effects* / Q000379:methods; D001955:British Columbia; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D012044:Regression Analysis; D014555:Urination Disorders / Q000453:epidemiology / Q000209:etiology*