title: Late urinary side effects 10 years after low-dose-rate prostate brachytherapy: population-based results from a multiphysician practice treating with a standardized protocol and uniform dosimetric goals.
abstract: OBJECTIVE
  To determine late urinary toxicity (>12 months) in a large cohort of uniformly treated low-dose-rate prostate brachytherapy patients.
  
  
  METHODS
  From 1998 to 2009, 2709 patients with National Comprehensive Cancer Network-defined low-risk and low-tier intermediate-risk prostate cancer were treated with Iodine 125 ((125)I) low-dose-rate prostate brachytherapy; 2011 patients with a minimum of 25 months of follow-up were included in the study. Baseline patients, treatment, implant factors, and late urinary toxicity (Radiation Therapy Oncology Group [RTOG] grading system and International Prostate Symptom Score [IPSS]) were recorded prospectively. Time to IPSS resolution, late RTOG genitourinary toxicity was examined with Kaplan-Meier and log-rank tests. Cox proportional hazards regression was done for individual covariates and multivariable models.
  
  
  RESULTS
  Median follow-up was 54.5 months (range, 2-13 years). Actuarial toxicity rates reached 27% and 10% (RTOG ≥2 and ≥3, respectively) at 9-13 years. Symptoms resolved quickly in the majority of patients (88% in 6-12 months). The prevalence of RTOG 0, 1, 2, 3, and 4 toxicity with a minimum of 7 years' follow-up was 70%, 21%, 6.4%, 2.3%, and 0.08%, respectively. Patients with a larger prostate volume, higher baseline IPSS, higher D90, acute toxicity, and age >70 years had more late RTOG ≥2 toxicity (all P≤.02). The IPSS resolved slower in patients with lower baseline IPSS and larger ultrasound prostate volume, those not receiving androgen deprivation therapy, and those with higher D90. The crude rate of RTOG 3 toxicity was 6%. Overall the rate of transurethral resection of the prostate was 1.9%; strictures, 2%; incontinence, 1.3%; severe symptoms, 1.8%; late catheterization, 1.3%; and hematuria, 0.8%. The majority (80%) resolved their symptoms in 6-12 months.
  
  
  CONCLUSIONS
  Long-term urinary toxicity after brachytherapy is low. Although actuarial rates increase with longer follow-up (27% RTOG 2 and 10% RTOG 3 at 13 years), symptoms resolve relatively quickly; between 5 and 13 years' follow-up, >90% of patients have minimal urinary toxicity. Refining patient selection criteria, planning, and treatment delivery may further reduce toxicity.
authors.affiliation: British Columbia Provincial Prostate Brachytherapy Program, British Columbia Cancer Agency, Vancouver, BC, Canada. Electronic address: mkeyes@bccancer.bc.ca.
authors.forename: Mira
authors.initials: M
authors.lastname: Keyes
authors.affiliation: British Columbia Provincial Prostate Brachytherapy Program, British Columbia Cancer Agency, Vancouver, BC, Canada.
authors.forename: Stacy
authors.initials: S
authors.lastname: Miller
authors.affiliation: British Columbia Provincial Prostate Brachytherapy Program, British Columbia Cancer Agency, Vancouver, BC, Canada.
authors.forename: Tom
authors.initials: T
authors.lastname: Pickles
authors.affiliation: British Columbia Provincial Prostate Brachytherapy Program, British Columbia Cancer Agency, Vancouver, BC, Canada.
authors.forename: Ross
authors.initials: R
authors.lastname: Halperin
authors.affiliation: British Columbia Provincial Prostate Brachytherapy Program, British Columbia Cancer Agency, Vancouver, BC, Canada.
authors.forename: Winkle
authors.initials: W
authors.lastname: Kwan
authors.affiliation: British Columbia Provincial Prostate Brachytherapy Program, British Columbia Cancer Agency, Vancouver, BC, Canada.
authors.forename: Vincent
authors.initials: V
authors.lastname: Lapointe
authors.affiliation: British Columbia Provincial Prostate Brachytherapy Program, British Columbia Cancer Agency, Vancouver, BC, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: McKenzie
authors.affiliation: British Columbia Provincial Prostate Brachytherapy Program, British Columbia Cancer Agency, Vancouver, BC, Canada.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Spadinger
authors.affiliation: British Columbia Provincial Prostate Brachytherapy Program, British Columbia Cancer Agency, Vancouver, BC, Canada.
authors.forename: Howard
authors.initials: H
authors.lastname: Pai
authors.affiliation: British Columbia Provincial Prostate Brachytherapy Program, British Columbia Cancer Agency, Vancouver, BC, Canada.
authors.forename: Elisa K
authors.initials: EK
authors.lastname: Chan
authors.affiliation: British Columbia Provincial Prostate Brachytherapy Program, British Columbia Cancer Agency, Vancouver, BC, Canada.
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; D007457:Iodine Radioisotopes / Q000009:adverse effects* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000453:epidemiology*; D013997:Time Factors; D014555:Urination Disorders / Q000453:epidemiology* / Q000209:etiology
chemical_list: D007457:Iodine Radioisotopes; D017430:Prostate-Specific Antigen