title: The dosimetric quality of brachytherapy implants in patients with small prostate volume depends on the experience of the brachytherapy team.
abstract: OBJECTIVE
  To investigate the dosimetric outcome of brachytherapy in patients with small prostate volume (PV).
  
  
  METHODS
  Forty-three patients with small PV (<25 cm(3)) as determined using transrectal ultrasound and 120 patients with non-small PV (>25 cm(3)) that had received (125)I seed implants were reviewed in a retrospective cohort study. Implantations were performed under transrectal ultrasound guidance, and the prescription dose was 145 Gy. A CT and MRI scan of the pelvis were performed 1 month after implantation for dosimetric study.
  
  
  RESULTS
  Compared with non-small PV patients, patients with small PV experienced larger 1-month edema (p<0.001); lower dose to 90% (the isodose enclosing 90% of PV and representing a minimum dose to that volume of the prostate [D(90)]) of the prostate (p=0.03); higher intracapsular seed density (p<0.001); and were less likely to achieve D(90)>or=140 Gy (p=0.013) in a postimplant dosimetric study. The number of patients with D(90)<140 Gy decreased steadily in both subsets of patients as the implant program matured (odds ratio=0.56 per year, p<0.001), but the small prostate group exhibited more improvement compared with the non-small prostate patients over the same time period. Multivariate analysis revealed that brachytherapy team experience rather than the size of prostate was a more important predictive factor of implant quality (p<0.001).
  
  
  CONCLUSIONS
  This single institution experience demonstrated a significant learning curve in the initial years of a prostate brachytherapy program, especially for patients with small prostates. A small prostate itself is not a contraindication of brachytherapy. The quality of implant for patients with small prostates depends more on the skill of the brachytherapy team.
authors.affiliation: Department of Radiation Oncology, CancerCare Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Liu
authors.forename: Kyle
authors.initials: K
authors.lastname: Malkoske
authors.forename: David
authors.initials: D
authors.lastname: Sasaki
authors.forename: Jeff
authors.initials: J
authors.lastname: Bews
authors.forename: Alain
authors.initials: A
authors.lastname: Demers
authors.forename: Zoann
authors.initials: Z
authors.lastname: Nugent
authors.forename: Aldrich
authors.initials: A
authors.lastname: Ong
authors.forename: Bashir
authors.initials: B
authors.lastname: Bashir
authors.forename: Tarek
authors.initials: T
authors.lastname: Dufan
authors.forename: Patrick
authors.initials: P
authors.lastname: Cho
authors.forename: Darryl
authors.initials: D
authors.lastname: Drachenberg
authors.forename: Amit
authors.initials: A
authors.lastname: Chowdhury
mesh_terms: D000368:Aged; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D011361:Professional Competence; D011467:Prostate / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000532:radiotherapy*; D011786:Quality Control; D011829:Radiation Dosage; D011874:Radiometry; D016896:Treatment Outcome