title: Early outcomes from three prospective trials of image-guided proton therapy for prostate cancer.
abstract: OBJECTIVE
  To report early outcomes with image-guided proton therapy for prostate cancer.
  
  
  METHODS
  We accrued 211 prostate cancer patients on prospective Institutional Review Board-approved trials of 78 cobalt gray equivalent (CGE) in 39 fractions for low-risk disease, dose escalation from 78 to 82 CGE for intermediate-risk disease, and 78 CGE with concomitant docetaxel followed by androgen deprivation for high-risk disease. Minimum follow-up was 2 years.
  
  
  RESULTS
  One intermediate-risk patient and 2 high-risk patients had disease progression. Pretreatment genitourinary (GU) symptom management was required in 38% of patients. A cumulative 88 (42%) patients required posttreatment GU symptom management. Four transient Grade 3 GU toxicities occurred, all among patients requiring pretreatment GU symptom management. Multivariate analysis showed correlation between posttreatment GU 2+ symptoms and pretreatment GU symptom management (p < 0.0001) and age (p = 0.0048). Only 1 Grade 3+ gastrointestinal (GI) symptom occurred. The prevalence of Grade 2+ GI symptoms was 0 (0%), 10 (5%), 12 (6%), and 8 (4%) at 6, 12, 18, and 24 months, with a cumulative incidence of 20 (10%) patients at 2 years after proton therapy. Univariate and multivariate analyses showed significant correlation between Grade 2+ rectal bleeding and proctitis and the percentage of rectal wall (rectum) receiving doses ranging from 40 CGE (10 CGE) to 80 CGE.
  
  
  CONCLUSIONS
  Early outcomes with image-guided proton therapy suggest high efficacy and minimal toxicity with only 1.9% Grade 3 GU symptoms and <0.5% Grade 3 GI toxicities.
authors.affiliation: University of Florida Proton Therapy Institute, Jacksonville, FL 32206, USA. menden@shands.ufl.edu
authors.forename: Nancy P
authors.initials: NP
authors.lastname: Mendenhall
authors.forename: Zuofeng
authors.initials: Z
authors.lastname: Li
authors.forename: Bradford S
authors.initials: BS
authors.lastname: Hoppe
authors.forename: Robert B
authors.initials: RB
authors.lastname: Marcus
authors.forename: William M
authors.initials: WM
authors.lastname: Mendenhall
authors.forename: R Charles
authors.initials: RC
authors.lastname: Nichols
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Morris
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Williams
authors.forename: Joseph
authors.initials: J
authors.lastname: Costa
authors.forename: Randal
authors.initials: R
authors.lastname: Henderson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000726:Androgen Antagonists / Q000627:therapeutic use; D018450:Disease Progression; D000077143:Docetaxel; D019583:Dose Fractionation, Radiation; D057918:Fiducial Markers; D006471:Gastrointestinal Hemorrhage / Q000209:etiology; D041981:Gastrointestinal Tract / Q000528:radiation effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D011472:Prostatitis / Q000209:etiology; D061766:Proton Therapy; D011838:Radiation-Sensitizing Agents / Q000627:therapeutic use; D061089:Radiotherapy, Image-Guided / Q000009:adverse effects / Q000379:methods*; D012007:Rectum / Q000528:radiation effects; D043823:Taxoids / Q000627:therapeutic use; D016896:Treatment Outcome; D014549:Urinary Incontinence / Q000209:etiology; D014566:Urogenital System / Q000528:radiation effects*
chemical_list: D000726:Androgen Antagonists; D011838:Radiation-Sensitizing Agents; D043823:Taxoids; D000077143:Docetaxel