title: The Quadrella: a novel approach to analyzing optimal outcomes after permanent seed prostate brachytherapy.
abstract: OBJECTIVE
  To study a four-point combined analysis (Quadrella) of optimal outcome among patients treated with exclusive permanent seed prostate brachytherapy (PB), as defined by the likelihood of achieving disease control and preserving normal urinary, gastro-intestinal (GI) and sexual function.
  
  
  METHODS
  384 patients with localized prostate cancer underwent PB at our institution with (125)I at a dose level of 144Gy. Subjects with erectile dysfunction who did not respond to medication were excluded. 281 patients with minimum 3-year follow-up were evaluated. Patients with concurrent biochemical progression-free survival (bPFS), absent urinary and GI toxicities (grade 0 toxicities according to CTCAE v 3.0) and preserved sexual potency (with our without medication) were classified as the Quadrella group.
  
  
  RESULTS
  Among the 281 patients analyzed, the Quadrella was achieved in 49.1%, 48.0%, 50.4%, 41.7% and 65.2% in years 3-7, respectively. bPFS rates were 82.6-96.1%, corresponding potency rates were 63.6-82.3%, and normal urinary and GI function rates were 64.8-82.6% and 95-100%, respectively. By multivariate analysis, significant predictors of Quadrella were age (p=0.015), baseline IPSS (p=0.03) and time since PB (p=0.02).
  
  
  CONCLUSIONS
  Urinary and sexual toxicity remained the most common reasons for excluding patients from a perfect outcome (Quadrella), defined by strict criteria. This analysis can be useful for subsequent comparison between treatment modalities.
authors.affiliation: Département de Radio-Oncologie, Centre hospitalier de l'Université de Montréal (CHUM) - Hôpital Notre-Dame, Canada; Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM), Canada.
authors.forename: Audrey
authors.initials: A
authors.lastname: Tétreault-Laflamme
authors.affiliation: Division of Radiation Oncology, Geneva University Hospital, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Zilli
authors.affiliation: Département de Radio-Oncologie, Centre hospitalier de l'Université de Montréal (CHUM) - Hôpital Notre-Dame, Canada.
authors.forename: Aliza
authors.initials: A
authors.lastname: Meissner
authors.affiliation: Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM), Canada.
authors.forename: Sandra
authors.initials: S
authors.lastname: Larrivée
authors.affiliation: Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM), Canada.
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Sylvestre
authors.affiliation: Département de Radio-Oncologie, Centre hospitalier de l'Université de Montréal (CHUM) - Hôpital Notre-Dame, Canada; Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM), Canada.
authors.forename: Guila
authors.initials: G
authors.lastname: Delouya
authors.affiliation: Département de Radio-Oncologie, Centre hospitalier de l'Université de Montréal (CHUM) - Hôpital Notre-Dame, Canada; Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM), Canada. Electronic address: daniel.taussky.chum@ssss.gouv.qc.ca.
authors.forename: Daniel
authors.initials: D
authors.lastname: Taussky
mesh_terms: D000368:Aged; D001918:Brachytherapy / Q000009:adverse effects / Q000379:methods* / Q000592:standards; D018572:Disease-Free Survival; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000008:administration & dosage* / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000175:diagnosis / Q000209:etiology; D012735:Sexual Dysfunction, Physiological / Q000175:diagnosis / Q000209:etiology; D016896:Treatment Outcome
chemical_list: D007457:Iodine Radioisotopes
keywords: Combined outcome; Prostate brachytherapy; Toxicity