title: Outpatient-based high-dose-rate interstitial brachytherapy for gynecologic malignancies.
abstract: OBJECTIVE
  To evaluate outpatient-based high-dose-rate (HDR) interstitial brachytherapy (ISBT) in the treatment of gynecologic malignancies.
  
  
  METHODS
  Between December 2006 and July 2012, 50 patients were treated with twice-daily outpatient-based HDR iridium-192 ISBT at our institution. Thirty-two patients had vaginal cancers, 13 vulvar, 3 urethral, and 2 cervical cancers. The most common histologies were squamous cell carcinoma (58%) and endometrioid adenocarcinoma (26%). Twenty-six patients were treated with definitive radiation therapy with or without platinum-based chemotherapy, 16 were treated for recurrent disease, 5 were treated in the postoperative setting, and 3 were treated palliatively. Forty patients received external beam radiation therapy before ISBT.
  
  
  RESULTS
  Median followup was 13.7 months. Median interstitial dose was 18 Gy in 2.25 Gy twice-daily fractions prescribed to the implant volume. Median external beam dose was 50.4 Gy in 1.8 Gy daily fractions prescribed to the primary disease site. Eight patients (16%) were seen in the emergency room or were admitted to the hospital during treatment. Six patients (17%) experienced significant complications after treatment (3 ulcerations at the primary site, 1 vaginal necrosis, 1 vaginal abscess, and 1 patient with urinary obstruction). Larger volume encompassing 100% of the prescribed dose was correlated with significant complications on multivariate analysis (p = 0.039). Actuarial local control at 1 year was 72%, with univariate analysis demonstrating worse local control for nonendometrioid adenocarcinoma compared with squamous cell carcinoma (20% vs. 84%, p = 0.044).
  
  
  CONCLUSIONS
  Outpatient-based HDR ISBT is feasible and safe, with toxicity and local control rates consistent with historical outcomes.
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO.
authors.forename: Pawel T
authors.initials: PT
authors.lastname: Dyk
authors.affiliation: Swedish Cancer Institute, Seattle, WA.
authors.forename: Susan
authors.initials: S
authors.lastname: Richardson
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO.
authors.forename: Shahed N
authors.initials: SN
authors.lastname: Badiyan
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO; Alvin J. Siteman Cancer Center, St. Louis, MO.
authors.forename: Julie K
authors.initials: JK
authors.lastname: Schwarz
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Esthappan
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO.
authors.forename: Jose L
authors.initials: JL
authors.lastname: Garcia-Ramirez
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO; Alvin J. Siteman Cancer Center, St. Louis, MO; Division of Nuclear Medicine, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO; Division of Gynecologic Oncology, Washington University School of Medicine, St. Louis, MO. Electronic address: pgrigsby@wustl.edu.
authors.forename: Perry W
authors.initials: PW
authors.lastname: Grigsby
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000379:methods*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005500:Follow-Up Studies; D005833:Genital Neoplasms, Female / Q000532:radiotherapy*; D006801:Humans; D008875:Middle Aged; D010045:Outpatients; D012189:Retrospective Studies
keywords: HDR; ISBT; Interstitial brachytherapy