title: Acute gastrointestinal and genitourinary toxicity of image-guided intensity modulated radiation therapy for prostate cancer using a daily water-filled endorectal balloon.
abstract: BACKGROUND
  Our purpose was to report acute gastrointestinal (GI) and genitourinary (GU) toxicity rates for prostate cancer patients undergoing image-guided intensity modulated radiation therapy (IG-IMRT) with a daily endorectal water-filled balloon (ERBH2O), and assess associations with planning parameters and pretreatment clinical characteristics.
  
  
  METHODS
  The first 100 patients undergoing prostate and proximal seminal vesicle IG-IMRT with indexed-lumen 100 cc ERBH2O to 79.2 Gy in 1.8 Gy fractions at our institution from 12/2008- 12/2010 were assessed. Pretreatment characteristics, organ-at-risk dose volume histograms, and maximum GU and GI toxicities (CTCAE 3.0) were evaluated. Logistic regression models evaluated univariate association between toxicities and dosimetric parameters, and uni- and multivariate association between toxicities and pretreatment characteristics.
  
  
  RESULTS
  Mean age was 68 (range 51-88). Thirty-two, 49, and 19 patients were low, intermediate, and high-risk, respectively; 40 received concurrent androgen deprivation. No grade 3 or greater toxicities were recorded. Maximum GI toxicity was grade 0, 1, and 2 in 69%, 23%, and 8%, respectively. Infield (defined as 1 cm above/below the CTV) rectal mean/median doses, D75, V30, and V40 and hemorrhoid history were associated with grade 2 GI toxicity (Ps < 0.05). Maximum acute GU toxicity was grade 0, 1, and 2 for 17%, 41%, and 42% of patients, respectively. Infield bladder V20 (P = 0.03) and pretreatment International Prostate Symptom Scale (IPSS) (P = 0.003) were associated with grade 2 GU toxicity.
  
  
  CONCLUSIONS
  Prostate IG-IMRT using a daily ERBH2O shows low rates of acute GI toxicity compared to previous reports of air-filled ERB IMRT when using stringent infield rectum constraints and comparable GU toxicities.
authors.affiliation: Department of Radiation Oncology, Pennsylvania, USA. deville@uphs.upenn.edu
authors.forename: Curtiland
authors.initials: C
authors.lastname: Deville
authors.forename: Stefan
authors.initials: S
authors.lastname: Both
authors.forename: Viet
authors.initials: V
authors.lastname: Bui
authors.forename: Wei-Ting
authors.initials: WT
authors.lastname: Hwang
authors.forename: Kay-See
authors.initials: KS
authors.lastname: Tan
authors.forename: Mattia
authors.initials: M
authors.lastname: Schaer
authors.forename: Zelig
authors.initials: Z
authors.lastname: Tochner
authors.forename: Neha
authors.initials: N
authors.lastname: Vapiwala
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D041981:Gastrointestinal Tract / Q000528:radiation effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D061089:Radiotherapy, Image-Guided / Q000009:adverse effects* / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects* / Q000379:methods*; D012189:Retrospective Studies; D014566:Urogenital System / Q000528:radiation effects