title: Volumetric image-guided highly conformal radiotherapy of the prostate bed: Toxicity analysis.
abstract: OBJECTIVE
  To evaluate toxicity of high conformal image-guided radiotherapy of the prostate bed.
  
  
  BACKGROUND
  Radiotherapy of the prostate bed has a pivotal role in the post-operative and salvage settings, but few clinical data are available on the use of daily image guidance in combination with highly conformal techniques, and data on long-term results are lacking.
  
  
  METHODS
  We analyzed 118 patients irradiated on the prostate bed using conformal plans processed with a micro-multileaf collimator, and daily checking treatment set-up with a cone-beam CT system. Correlation between toxicity and clinical-dosimetric parameters was assessed by the Cox regression model and log-rank test. Survival analyses were performed with the Kaplan-Meier method.
  
  
  RESULTS
  Median follow-up was 54.08 months. Late grade ≥2 gastro-intestinal (GI) and genito-urinary (GU) toxicity were 3.4% and 4.2%, respectively. Actuarial 4-year late grade ≥2 GI and GU toxicities were 4% and 6%, respectively. Four-year relapse-free survival was 87%. At log-rank test, acute grade ≥2 GI toxicity is associated with the use of antihypertensives (p= 0.03), and there is a trend toward significance between the use of anticoagulants and late grade ≥2 GI toxicity (p= 0.07). At Cox analysis, acute grade ≥2 GU toxicity is correlated with the percentage of bladder volume receiving more than 65 Gy (p= 0.02, HR 1.87 CI 1.25-2.8), and the maximal dose to the rectum is correlated to the development of late grade ≥2 GI toxicity (p= 0.03, HR 2.75 CI 1.10-6.9).
  
  
  CONCLUSIONS
  Conformal volumetric image-guided radiotherapy of the prostate bed leads to low toxicity rates.
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata General Hospital, Rome, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Ingrosso
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata General Hospital, Rome, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Carosi
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata General Hospital, Rome, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: di Cristino
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata General Hospital, Rome, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Ponti
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata General Hospital, Rome, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Lancia
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata General Hospital, Rome, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Murgia
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata General Hospital, Rome, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Bruni
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata General Hospital, Rome, Italy.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Morelli
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata General Hospital, Rome, Italy.
authors.forename: Franca
authors.initials: F
authors.lastname: Pietrasanta
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata General Hospital, Rome, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Santoni
keywords: Conformal radiotherapy; Image-guided radiotherapy; Prostate bed; Toxicity