title: Combining high dose external beam radiotherapy with a simultaneous integrated boost to the dominant intraprostatic lesion: Analysis of genito-urinary and rectal toxicity.
abstract: Local recurrences after radiotherapy are dose-dependent and occur in the dominant intraprostatic lesion (DIL). The purpose of this study was to evaluate the impact of a simultaneous integrated boost (SIB) to the magnetic resonance imaging (MRI)-defined DIL on toxicity.
  
  
  
  Four-hundred and ten patients were treated with intensity-modulated radiotherapy. A median dose of 78Gy was prescribed to the prostate. A SIB of 82Gy to the DIL was performed in 225 patients (SIB+). Genitourinary and rectal toxicity on fixed time points up to 8years were compared between SIB- (185 patients) and SIB+ patients. Chi-square, Fisher's exact and Kaplan-Meier statistics were applied. With a median follow up of 72months, the six-year actuarial risk of genitourinary and rectal toxicity grade⩾2 was 31% and 12% respectively. The actuarial risk of developing toxicity and incidence of symptoms at fixed time points were not increased with a SIB.
  
  
  
  Performing a SIB did not increase genitourinary or rectal toxicity up to 8years' follow-up.
authors.affiliation: Ghent University Hospital, Department of Radiation Oncology and Experimental Cancer Research, Belgium.
authors.forename: Nora
authors.initials: N
authors.lastname: Sundahl
authors.affiliation: Ghent University Hospital, Department of Radiation Oncology and Experimental Cancer Research, Belgium.
authors.forename: Gert
authors.initials: G
authors.lastname: De Meerleer
authors.affiliation: Ghent University Hospital, Department of Radiology, Belgium.
authors.forename: Geert
authors.initials: G
authors.lastname: Villeirs
authors.affiliation: Ghent University Hospital, Department of Radiation Oncology and Experimental Cancer Research, Belgium.
authors.forename: Piet
authors.initials: P
authors.lastname: Ost
authors.affiliation: Ghent University Hospital, Department of Radiation Oncology and Experimental Cancer Research, Belgium.
authors.forename: Wilfried
authors.initials: W
authors.lastname: De Neve
authors.affiliation: Ghent University Hospital, Department of Urology, Belgium.
authors.forename: Nicolaas
authors.initials: N
authors.lastname: Lumen
authors.affiliation: Ghent University Hospital, Department of Radiology, Belgium.
authors.forename: Pieter
authors.initials: P
authors.lastname: De Visschere
authors.affiliation: Ghent University Hospital, Department of Radiation Oncology and Experimental Cancer Research, Belgium.
authors.forename: Marc
authors.initials: M
authors.lastname: Van Eijkeren
authors.affiliation: Ghent University Hospital, Department of Radiation Oncology and Experimental Cancer Research, Belgium. Electronic address: Valerie.fonteyne@uzgent.be.
authors.forename: Valérie
authors.initials: V
authors.lastname: Fonteyne
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D058958:Organs at Risk; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D012007:Rectum / Q000528:radiation effects*; D014566:Urogenital System / Q000528:radiation effects*
keywords: Dose escalation; Intraprostatic lesion; Prostate cancer; Toxicity