title: Combined proton and photon conformal radiation therapy for locally advanced carcinoma of the prostate: preliminary results of a phase I/II study.
abstract: OBJECTIVE
  A study was developed to evaluate the use of combined photons and protons for the treatment of locally advanced carcinoma of the prostate. This report is a preliminary assessment of treatment-related morbidity and tumor response.
  
  
  METHODS
  One hundred and six patients in stages T2b (B2), T2c (B2), and T3 (C) were treated with 45 Gy photon-beam irradiation to the pelvis and an additional 30 Cobalt Gray Equivalent (CGE) to the prostate with 250-MeV protons, yielding a total prostate dose of 75 CGE in 40 fractions. Median follow-up time was 20.2 months (range: 10-30 months). Toxicity was scored according to the Radiation Therapy Oncology Group (RTOG) grading system; local control was evaluated by serial digital rectal examination (DRE) and prostate specific antigen (PSA) measurements.
  
  
  RESULTS
  Morbidity evaluation was available on 104 patients. The actuarial 2-year rate of Grade 1 or 2 late morbidity was 12% (8% rectal, 4% urinary). No patients demonstrated Grade 3 or 4 late morbidity. Treatment response was evaluated on 100 patients with elevated pretreatment serum PSA levels. The actuarial 2-year rate of PSA normalization was 96%, 97%, and 63% for pretreatment PSAs of > 4-10, > 10-20, and > 20, respectively. The 13 patients with rising PSA demonstrated local recurrence (3 patients), distant metastasis (8 patients), or no evidence of disease except increasing PSA (2 patients).
  
  
  CONCLUSIONS
  The low incidence of side effects, despite the tumor dose of 75 CGE, demonstrates that conformal protons can deliver higher doses of radiation to target tissues without increasing complications to surrounding normal tissues. The initial tumor response, as assessed by the high actuarial rate of normalization with pretreatment PSA < or = 20, and the low rate of recurrences within the treatment field (2.8%), are encouraging.
authors.affiliation: Department of Radiation Medicine, Loma Linda University Medical Center, CA 92354, USA.
authors.forename: L T
authors.initials: LT
authors.lastname: Yonemoto
authors.forename: J D
authors.initials: JD
authors.lastname: Slater
authors.forename: C J
authors.initials: CJ
authors.lastname: Rossi
authors.forename: J E
authors.initials: JE
authors.lastname: Antoine
authors.forename: L
authors.initials: L
authors.lastname: Loredo
authors.forename: J O
authors.initials: JO
authors.lastname: Archambeau
authors.forename: R W
authors.initials: RW
authors.lastname: Schulte
authors.forename: D W
authors.initials: DW
authors.lastname: Miller
authors.forename: S L
authors.initials: SL
authors.lastname: Teichman
authors.forename: J M
authors.initials: JM
authors.lastname: Slater
mesh_terms: D000230:Adenocarcinoma / Q000097:blood / Q000473:pathology / Q000532:radiotherapy*; D000368:Aged; D000369:Aged, 80 and over; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000097:blood; D009367:Neoplasm Staging; D017785:Photons / Q000627:therapeutic use*; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology / Q000532:radiotherapy*; D061766:Proton Therapy; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted
chemical_list: D009363:Neoplasm Proteins; D017430:Prostate-Specific Antigen