title: Long term results of a prospective dose escalation phase-II trial: interstitial pulsed-dose-rate brachytherapy as boost for intermediate- and high-risk prostate cancer.
abstract: OBJECTIVE
  We reviewed our seven year single institution experience with pulsed dose rate brachytherapy dose escalation study in patients with intermediate and high risk prostate cancer.
  
  
  METHODS
  We treated a total of 130 patients for intermediate and high risk prostate cancer at our institution between 2000 and 2007 using PDR-brachytherapy as a boost after conformal external beam radiation therapy to 50.4 Gy. The majority of patients had T2 disease (T1c 6%, T2 75%, T3 19%). Seventy three patients had intermediate-risk and 53 patients had high-risk disease according to the D'Amico classification. The dose of the brachytherapy boost was escalated from 25 to 35 Gy - 33 pts. received 25 Gy (total dose 75 Gy), 63 pts. 30 Gy (total dose 80 Gy) and 34 pts. 35 Gy, (total dose 85 Gy) given in one session (dose per pulse was 0.60 Gy or 0.70 Gy/h, 24h per day, night and day, with a time interval of 1h between two pulses). PSA-recurrence-free survival according to Kaplan-Meier using the Phoenix definition of biochemical failure was calculated and also late toxicities according to Common Toxicity Criteria scale were assessed.
  
  
  RESULTS
  At the time of analysis with a median follow-up of 60 months biochemical control was achieved by 88% of patients - only 16/130 patients (12.3%) developed a biochemical relapse. Biochemical relapse free survival calculated according to Kaplan-Meier for all patients at 5 years was 85.6% (83.9% for intermediate-risk patients and 84.2% for high-risk patients) and at 9 years' follow up it was 79.0%. Analysing biochemical relapse free survival separately for different boost dose levels, at 5 years it was 97% for the 35 Gy boost dose and 82% for the 25 and 30 Gy dose levels. The side effects of therapy were negligible: There were 18 cases (15%) of grade 1/2 rectal proctitis, one case (0.8%) of grade 3 proctitis, 18 cases (15%) of grade 1/2 cystitis, and no cases (0%) with dysuria grade 3. No patient had a bulbourethral stricture requiring dilation or new onset incontinence.
  
  
  CONCLUSIONS
  Image-guided conformal PDR-brachytherapy using up to 35 Gy as boost dose after 50 Gy of external beam radiation therapy (total dose up to 85 Gy) is a very effective treatment option with very low morbidity in patients with intermediate or high risk prostate cancer. Further dose escalation seems possible.
authors.affiliation: University Hospital Erlangen, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Lettmaier
authors.forename: Michael
authors.initials: M
authors.lastname: Lotter
authors.forename: Stephan
authors.initials: S
authors.lastname: Kreppner
authors.forename: Annedore
authors.initials: A
authors.lastname: Strnad
authors.forename: Rainer
authors.initials: R
authors.lastname: Fietkau
authors.forename: Vratislav
authors.initials: V
authors.lastname: Strnad
mesh_terms: D000368:Aged; D001918:Brachytherapy / Q000009:adverse effects / Q000379:methods*; D018572:Disease-Free Survival; D019583:Dose Fractionation, Radiation; D004307:Dose-Response Relationship, Radiation; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D009361:Neoplasm Invasiveness / Q000473:pathology; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D009367:Neoplasm Staging; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000401:mortality / Q000473:pathology* / Q000532:radiotherapy*; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000517:prevention & control; D020266:Radiotherapy, Conformal / Q000009:adverse effects / Q000379:methods*; D018570:Risk Assessment; D018709:Statistics, Nonparametric; D016019:Survival Analysis; D013995:Time; D016896:Treatment Outcome
chemical_list: D017430:Prostate-Specific Antigen