title: Intensity-modulated radiotherapy for squamous cell carcinoma of the anal canal: efficacy of a low daily dose to clinically negative regions.
abstract: BACKGROUND
  We aimed to assess outcomes of patients with anal cancer who underwent intensity-modulated radiotherapy (IMRT) and received less than 1.80 Gy/day.
  
  
  METHODS
  We retrospectively reviewed our experience using a low fractional dose (< 1.80 Gy) of IMRT to elective nodal areas for patients receiving chemoradiotherapy for anal cancer. Three-year freedom from any disease relapse and overall survival were estimated using Kaplan-Meier curves. We documented the daily dose that was delivered to clinically uninvolved regions and to areas of gross disease. Incidence of regional failures in high (≥ 1.80 Gy) and low (< 1.80 Gy) daily dose regions was assessed.
  
  
  RESULTS
  Thirty-four consecutive patients (median age, 59 years) received IMRT from June 2005 through January 2009. Median follow-up duration was 22 months. Twenty-eight patients had T1 or T2 disease and 6 had T3 or T4 disease. Fourteen patients had nodal metastases. Median treatment dose was 50.40 Gy (range, 48.60-57.60 Gy) in 25 to 32 fractions. The range of fractional doses to clinically negative volumes was 1.28 to 1.80 Gy. Seventeen patients (50%) received a fractional dose of less than 1.60 Gy, 13 (38%) received less than 1.50 Gy, and 9 (26%) received less than 1.40 Gy to at least a portion of the clinically negative volume. Three-year freedom from relapse was 80%, and 3-year overall survival was 87%. No patient had treatment failure in the clinically negative volume that received a low daily dose.
  
  
  CONCLUSIONS
  Our data support using doses between 1.50 and 1.80 Gy/day to clinically uninvolved regions.
authors: Department of Radiation Oncology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA.
authors: Jason A
authors: JA
authors: Call
authors: Michael G
authors: MG
authors: Haddock
authors: J Fernando
authors: JF
authors: Quevedo
authors: David W
authors: DW
authors: Larson
authors: Robert C
authors: RC
authors: Miller
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001005:Anus Neoplasms / Q000188:drug therapy / Q000532:radiotherapy*; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000532:radiotherapy*; D059248:Chemoradiotherapy / Q000379:methods; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008875:Middle Aged; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012008:Recurrence; D012189:Retrospective Studies; D016896:Treatment Outcome