title: Results from the Quality Research in Radiation Oncology (QRRO) survey: Evaluation of dosimetric outcomes for low-dose-rate prostate brachytherapy.
abstract: OBJECTIVE
  We report on quality of dose delivery to target and normal tissues from low-dose-rate prostate brachytherapy using postimplantation dosimetric evaluations from a random sample of U.S. patients.
  
  
  METHODS
  Nonmetastatic prostate cancer patients treated with external beam radiotherapy or brachytherapy in 2007 were randomly sampled from radiation oncology facilities nationwide. Of 414 prostate cancer cases from 45 institutions, 86 received low-dose-rate brachytherapy. We collected the 30-day postimplantation CT images of these patients and 10 test cases from two other institutions. Scans were downloaded into a treatment planning system and prostate/rectal contours were redrawn. Dosimetric outcomes were reanalyzed and compared with calculated outcomes from treating institutions.
  
  
  RESULTS
  Median prostate volume was 33.4cm(3). Reevaluated median V(100), D(90), and V(150) were 91.1% (range, 45.5-99.8%), 101.7% (range, 59.6-145.9%), and 53.9% (range, 15.7-88.4%), respectively. Low gland coverage included 27 patients (39%) with a D(90) lower than 100% of the prescription dose (PD), 12 of whom (17% of the entire group) had a D(90) lower than 80% of PD. There was no correlation between D(90) coverage and prostate volume, number of seeds, or implanted activity. The median V(100) for the rectum was 0.3cm(3) (range, 0-4.3cm(3)). No outcome differences were observed according to the institutional strata. Concordance between reported and reevaluated D(90) values (defined as within ±10%) was observed in 44 of 69 cases.
  
  
  CONCLUSIONS
  Central review of postimplantation CT scans to assess the quality of prostate brachytherapy is feasible. Most patients achieved excellent dosimetric outcomes, yet 17% had less than optimal target coverage by the PD. There was concordance between submitted target-coverage parameters and central dosimetric review in 64% of implants. These findings will require further validation in a larger cohort of patients.
authors: Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA. zelefskm@mskcc.org
authors: Michael J
authors: MJ
authors: Zelefsky
authors: Gil'ad N
authors: GN
authors: Cohen
authors: Walter R
authors: WR
authors: Bosch
authors: Lisa
authors: L
authors: Morikawa
authors: Najma
authors: N
authors: Khalid
authors: Cheryl L
authors: CL
authors: Crozier
authors: W Robert
authors: WR
authors: Lee
authors: Anthony
authors: A
authors: Zietman
authors: Jean
authors: J
authors: Owen
authors: J Frank
authors: JF
authors: Wilson
authors: Phillip M
authors: PM
authors: Devlin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000592:standards* / Q000706:statistics & numerical data; D019538:Health Care Surveys; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000453:epidemiology* / Q000532:radiotherapy*; D011785:Quality Assurance, Health Care / Q000592:standards* / Q000706:statistics & numerical data; D011874:Radiometry / Q000592:standards* / Q000706:statistics & numerical data; D011879:Radiotherapy Dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000592:standards* / Q000706:statistics & numerical data; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology