title: Intensity modulated radiotherapy for localized prostate cancer: rigid compliance to dose-volume constraints as a warranty of acceptable toxicity?
abstract: BACKGROUND
  To report the toxicity after intensity modulated radiotherapy (IMRT) for patients with localized prostate cancer, as a sole treatment or after radical prostatectomy.
  
  
  METHODS
  Between August 2001 and December 2003, 132 patients with prostate cancer were treated with IMRT and 125 were evaluable to acute and late toxicity analysis, after a minimum follow-up time of one year. Clinical and treatment data, including normal tissue dose-volume histogram (DVH) constraints, were reviewed. Gastro-intestinal (GI) and genito-urinary (GU) signs and symptoms were evaluated according to the Radiation Therapy Oncology Group (RTOG) toxicity scales. Median prescribed dose was 76 Gy. Median follow-up time was of 26.1 months.
  
  
  RESULTS
  From the 125 patients, 73 (58.4%) presented acute Grade 1 or Grade 2 GI and 97 (77.2%) presented acute Grade 1 or Grade 2 GU toxicity. Grade 3 GI acute toxicity occurred in only 2 patients (1.6%) and Grade 3 GU acute toxicity in only 3 patients (2.4%). Regarding Grade 1 and 2 late toxicity, 26 patients (20.8%) and 21 patients (16.8%) presented GI and GU toxicity, respectively. Grade 2 GI late toxicity occurred in 6 patients (4.8%) and Grade 2 GU late toxicity in 4 patients (3.2%). None patient presented any Grade 3 or higher late toxicity. Non-conformity to DVH constraints occurred in only 11.2% of treatment plans. On univariate analysis, no significant risk factor was identified for Grade 2 GI late toxicity, but mean dose delivered to the PTV was associated to higher Grade 2 GU late toxicity (p = 0.042).
  
  
  CONCLUSIONS
  IMRT is a well tolerable technique for routine treatment of localized prostate cancer, with short and medium-term acceptable toxicity profiles. According to the data presented here, rigid compliance to DHV constraints might prevent higher incidences of normal tissue complication.
authors.affiliation: Department of Radiation Oncology, Hospital Israelita Albert Einstein, Av, Albert Einstein, 627/701 - Sao Paulo, Brazil. michael.chen@ig.com.br
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Chen
authors.forename: Eduardo
authors.initials: E
authors.lastname: Weltman
authors.forename: Rodrigo M
authors.initials: RM
authors.lastname: Hanriot
authors.forename: Fábio P
authors.initials: FP
authors.lastname: Luz
authors.forename: Paulo J
authors.initials: PJ
authors.lastname: Cecílio
authors.forename: José C
authors.initials: JC
authors.lastname: da Cruz
authors.forename: Frederico R
authors.initials: FR
authors.lastname: Moreira
authors.forename: Adriana S
authors.initials: AS
authors.lastname: Santos
authors.forename: Lidiane C
authors.initials: LC
authors.lastname: Martins
authors.forename: Wladmir
authors.initials: W
authors.lastname: Nadalin
mesh_terms: D000368:Aged; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D006973:Hypertension / Q000150:complications; D008297:Male; D008875:Middle Aged; D011468:Prostatectomy / Q000379:methods; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000209:etiology*; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects* / Q000379:methods*; D012306:Risk; D012307:Risk Factors; D016896:Treatment Outcome