title: Predicting genitourinary toxicity in three-dimensional conformal radiotherapy for localized prostate cancer: A dose-volume parameters analysis of the bladder.
abstract: OBJECTIVE
  In prostate cancer radiotherapy, the relationship between genitourinary (GU) toxicity and clinical-dosimetric parameters is debated. We report our analysis of the parameters associated with GU toxicity.
  
  
  METHODS
  Eighty-six consecutive patients treated with conformal radiotherapy for localized prostate cancer were retrospectively analyzed; the bladder was delineated both as "whole bladder" (WB: Defined in its entirety as a solid organ) and "inferior bladder" (IB: Corresponding to the distal part of the bladder). GU toxicity and dose-volume parameters were correlated using the point biserial correlation coefficient. The normal tissue complication probability (NTCP) cut-off volume model was fitted to toxicity data; univariate analysis between GU toxicity and clinical parameters was done.
  
  
  RESULTS
  Acute GU toxicity was correlated to doses higher than 80 Gy (P < 0.05) while late GU was correlated to doses higher than 77 Gy for WB and from 77.5 Gy for IB. The NTCP cut-off volume model identified for both WB and IB a bladder volume of 6 cc receiving a dose ≥77 Gy corresponding to a 50% probability of GU toxicity. At univariate analysis, acute GU toxicity was correlated with smoke (P < 0.001).
  
  
  CONCLUSIONS
  Bladder maximal doses quantified as hotspots show a correlation to GU toxicity.
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, University of Rome Tor Vergata, Viale Oxford 81, 00133 Rome, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Bagalà
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, University of Rome Tor Vergata, Viale Oxford 81, 00133 Rome, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Ingrosso
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, University of Rome Tor Vergata, Viale Oxford 81, 00133 Rome, Italy.
authors.forename: Maria Daniela
authors.initials: MD
authors.lastname: Falco
authors.affiliation: Computer Science and Bioinformatics Laboratory, Integrated Research Centre, Campus Bio-Medico University, Via Alvaro del Portillo 21, 00128, Rome, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Petrichella
authors.affiliation: Laboratory of Medical Physics and Expert Systems, National Cancer Institute Regina Elena, V. E. Chianesi 53, 00144 Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: D'Andrea
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, University of Rome Tor Vergata, Viale Oxford 81, 00133 Rome, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Rago
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, University of Rome Tor Vergata, Viale Oxford 81, 00133 Rome, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Lancia
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, University of Rome Tor Vergata, Viale Oxford 81, 00133 Rome, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Bruni
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, University of Rome Tor Vergata, Viale Oxford 81, 00133 Rome, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Ponti
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, University of Rome Tor Vergata, Viale Oxford 81, 00133 Rome, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Santoni
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003131:Combined Modality Therapy; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000188:drug therapy / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000175:diagnosis*; D011874:Radiometry; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects* / Q000379:methods*; D001743:Urinary Bladder / Q000528:radiation effects*