title: Implementation and early clinical results utilizing Cs-131 permanent interstitial implants for gynecologic malignancies.
abstract: OBJECTIVE
  Permanent interstitial brachytherapy is an ideal yet underutilized treatment modality for accessible, small volume gynecological malignancies. We present early clinical results utilizing a new permanent isotope, Cs-131.
  
  
  METHODS
  A retrospective review was performed evaluating patients treated with Cs-131 permanent interstitial radiation at our institution from July 2011 through June 2013. Doses were most commonly prescribed and calculated to a depth of 5mm using Paterson-Parker planar implant rules for Au-198. This activity was converted to air-kerma strength (U). A conversion factor of 1.1 was applied based on RBE calculations, clinical observation and experience.
  
  
  RESULTS
  14 patients were identified among whom 17 Cs-131 implants were performed. Seven patients were implanted as sole therapy, and a median dose of 50 Gy was delivered. Ten implants were performed as boost within a more extensive radiation treatment plan. In these patients, a median implant dose of 27.5 Gy was used and the median total dose delivered in combination was 78.25 Gy. After a median follow up of 12 months, the actuarial local control rate was 84.4%. A very low level of grade 1-3 reactions was observed with no fistula formations or other severe side effects.
  
  
  CONCLUSIONS
  Permanent interstitial brachytherapy with Cs-131 was well tolerated with favorable early results compared to other series. Cs-131 has multiple favorable properties, including minimal radiation exposure to treating staff, and should be considered as a therapeutic option in appropriately selected patients. A methodology for dose prescription, calculation of radioactivity required and distribution of the isotope is also presented.
authors.affiliation: Department of Radiation Medicine, Markey Cancer Center, University of Kentucky, Lexington, KY, USA.
authors.forename: Charles Eric
authors.initials: CE
authors.lastname: Wooten
authors.affiliation: Department of Radiation Medicine, Markey Cancer Center, University of Kentucky, Lexington, KY, USA.
authors.forename: Marcus
authors.initials: M
authors.lastname: Randall
authors.affiliation: Department of Radiation Medicine, Markey Cancer Center, University of Kentucky, Lexington, KY, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Edwards
authors.affiliation: Division of Medical Physics, Markey Cancer Center, University of Kentucky, Lexington, KY, USA.
authors.forename: Prakash
authors.initials: P
authors.lastname: Aryal
authors.affiliation: Division of Medical Physics, Markey Cancer Center, University of Kentucky, Lexington, KY, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Luo
authors.affiliation: Department of Radiation Medicine, Markey Cancer Center, University of Kentucky, Lexington, KY, USA. Electronic address: jmfedd0@email.uky.edu.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Feddock
mesh_terms: D000230:Adenocarcinoma / Q000532:radiotherapy*; D018262:Adenocarcinoma, Clear Cell / Q000532:radiotherapy; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000379:methods*; D002291:Carcinoma, Papillary / Q000532:radiotherapy*; D002294:Carcinoma, Squamous Cell / Q000532:radiotherapy*; D002588:Cesium Radioisotopes / Q000627:therapeutic use*; D015331:Cohort Studies; D018572:Disease-Free Survival; D016889:Endometrial Neoplasms / Q000532:radiotherapy; D005185:Fallopian Tube Neoplasms / Q000532:radiotherapy; D005260:Female; D005833:Genital Neoplasms, Female / Q000532:radiotherapy*; D006801:Humans; D008545:Melanoma / Q000532:radiotherapy*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000532:radiotherapy*; D012189:Retrospective Studies; D016896:Treatment Outcome; D002583:Uterine Cervical Neoplasms / Q000532:radiotherapy*; D014625:Vaginal Neoplasms / Q000532:radiotherapy
chemical_list: D002588:Cesium Radioisotopes
keywords: Brachytherapy; Cs-131; Gynecologic cancer; Interstitial radiation; Radiation implant; Re-irradiation