title: Five-Year Biochemical Results, Toxicity, and Patient-Reported Quality of Life After Delivery of Dose-Escalated Image Guided Proton Therapy for Prostate Cancer.
abstract: OBJECTIVE
  To report clinical outcomes in patients treated with image guided proton therapy (PT) for localized prostate cancer.
  
  
  METHODS
  The medical records of 1327 men were reviewed. Each man was enrolled on an outcomes tracking study. Dual enrollment on a prospective clinical trial was allowed. Each patient was treated for localized prostate cancer with PT at our institution between 2006 and 2010. Ninety-eight percent of patients received 78 Gy (radiobiological equivalent [RBE]) or higher; 18% received androgen deprivation therapy (ADT). The 5-year freedom from biochemical progression (FFBP), distant metastasis-free survival, and cause-specific survival rates are reported for each risk group. Data on patient-reported quality of life and high-grade toxicities were prospectively collected and reported. A multivariate analysis was performed to identify clinical predictors of biochemical failure and urologic toxicity.
  
  
  RESULTS
  The median follow-up time was 5.5 years. The 5-year FFBP rates were 99%, 94%, and 74% in low-risk, intermediate-risk, and high-risk patients, respectively. The actuarial 5-year rates of late grade 3+ Common Terminology Criteria for Adverse Events, version 4.0, gastrointestinal (GI) and genitourinary (GU) toxicity were 0.6% and 2.9%, respectively. Multivariate analysis showed a significant correlation between grade 3+ GU toxicity and pretreatment prostate reductive procedures (P<.0001), prostate volume (P=.0085), pretreatment α-blockers (P=.0067), diabetes (P=.0195), and dose-volume histogram parameters (P=.0208). The median International Prostate Symptom Scores pretreatment scores and scores at 5 years after treatment were 7 and 7, respectively. The mean Expanded Prostate Cancer Index Composite (EPIC) scores significantly declined for sexual summary for patients not receiving ADT (from 67 to 53) between baseline and 5 years.
  
  
  CONCLUSIONS
  Image guided PT provided excellent biochemical control rates for patients with localized prostate cancer. The actuarial rates of high-grade toxicity were low after PT. From pretreatment to 5 years of follow-up, a significant decline was found only in mean EPIC sexual summary scores. Prospective clinical studies are needed to determine the comparative effectiveness of PT and other radiation treatment strategies.
authors.affiliation: University of Florida Health Proton Therapy Institute, Jacksonville, Florida. Electronic address: cbryant@floridaproton.org.
authors.forename: Curtis
authors.initials: C
authors.lastname: Bryant
authors.affiliation: University of Florida Health Proton Therapy Institute, Jacksonville, Florida.
authors.forename: Tamara L
authors.initials: TL
authors.lastname: Smith
authors.affiliation: University of Florida Health Proton Therapy Institute, Jacksonville, Florida.
authors.forename: Randal H
authors.initials: RH
authors.lastname: Henderson
authors.affiliation: University of Florida Health Proton Therapy Institute, Jacksonville, Florida.
authors.forename: Bradford S
authors.initials: BS
authors.lastname: Hoppe
authors.affiliation: University of Florida Health Proton Therapy Institute, Jacksonville, Florida.
authors.forename: William M
authors.initials: WM
authors.lastname: Mendenhall
authors.affiliation: University of Florida Health Proton Therapy Institute, Jacksonville, Florida.
authors.forename: R Charles
authors.initials: RC
authors.lastname: Nichols
authors.affiliation: University of Florida Health Proton Therapy Institute, Jacksonville, Florida.
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Morris
authors.affiliation: Department of Urology, University of Florida College of Medicine, Jacksonville, Florida.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Williams
authors.affiliation: University of Florida Health Proton Therapy Institute, Jacksonville, Florida.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Su
authors.affiliation: University of Florida Health Proton Therapy Institute, Jacksonville, Florida.
authors.forename: Zuofeng
authors.initials: Z
authors.lastname: Li
authors.affiliation: University of Florida Health Proton Therapy Institute, Jacksonville, Florida.
authors.forename: Derek
authors.initials: D
authors.lastname: Lee
authors.affiliation: University of Florida Health Proton Therapy Institute, Jacksonville, Florida.
authors.forename: Nancy P
authors.initials: NP
authors.lastname: Mendenhall
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000726:Androgen Antagonists / Q000627:therapeutic use; D018572:Disease-Free Survival; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D058958:Organs at Risk; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D061766:Proton Therapy / Q000009:adverse effects / Q000379:methods*; D011788:Quality of Life; D011832:Radiation Injuries / Q000473:pathology; D011879:Radiotherapy Dosage; D061089:Radiotherapy, Image-Guided / Q000009:adverse effects / Q000379:methods*; D012062:Relative Biological Effectiveness; D013997:Time Factors
chemical_list: D000726:Androgen Antagonists; D017430:Prostate-Specific Antigen