PURPOSE: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.
MATERIALS AND 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 50.4Gy. 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 35Gy - 33pts. received 25Gy (total dose 75Gy), 63pts. 30Gy (total dose 80Gy) and 34pts. 35Gy, (total dose 85Gy) given in one session (dose per pulse was 0.60Gy or 0.70Gy/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 60months 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 5years was 85.6% (83.9% for intermediate-risk patients and 84.2% for high-risk patients) and at 9years' follow up it was 79.0%. Analysing biochemical relapse free survival separately for different boost dose levels, at 5years it was 97% for the 35Gy boost dose and 82% for the 25 and 30Gy 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 35Gy as boost dose after 50Gy of external beam radiation therapy (total dose up to 85Gy) is a very effective treatment option with very low morbidity in patients with intermediate or high risk prostate cancer. Further dose escalation seems possible.
Written by:
Lettmaier S, Lotter M, Kreppner S, Strnad A, Fietkau R, Strnad V. Are you the author?
University Hospital Erlangen, Germany.
Reference: Radiother Oncol. 2012 Aug;104(2):181-6.
doi: 10.1016/j.radonc.2012.07.003
PubMed Abstract
PMID: 22853851
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