Does microwave interstitial hyperthermia prior to high-dose-rate brachytherapy change prostate volume or therapy plan parameters?

PURPOSE: In this prospective preliminary study we evaluated changes of prostate volume and changes of brachytherapy treatment plan parameters due to interstitial hyperthermia (IHT) applied prior to high-dose-rate brachytherapy (HDRBT), compared to our standard HDRBT procedure. MATERIAL AND METHODS: In a group of 60 consecutive patients with prostate adenocarcinoma, 30 were treated with HDRBT alone and 30 with IHT preceding HDRBT. Prior to catheter implantation, a 'virtual' treatment plan (VP) was complied, a 'live' plan (LP) was prepared before patient irradiation, and a 'post' plan (PP) was drawn up after completing the irradiation procedure. In each plan, based on transrectal ultrasound images, the contours of the prostate, urethra, and rectum were delineated and the respective volumes and dose-volume histogram parameters were evaluated. These parameters, established for the LP, were then compared with those of the PP. RESULTS: Changes in prostate volume and in parameters of the treatment plans were observed, but differences between the two patient groups were not statistically significant. For all 60 patients treated, the average prostate volume in the VP was 32 cm(3), in the LP 41 cm(3), and the PP 43 cm(3). Average values of relative changes in the therapy planning parameters between LP and PP were for the prostate D90 -5.7%, V100 -5.6%, V200 -13.2%, for the urethra D0, 1 cm(3) -1.6%, and for rectum D2 cm(3) 0%. CONCLUSION: Hyperthermia prior to HDRBT does not significantly change the volume of the prostate and there is no need to perform the new treatment plan after the hyperthermia session.

High-dose-rate brachytherapy as a monotherapy for prostate cancer--Single-institution results of the extreme fractionation regimen.

PURPOSE: We report a single-institution retrospective analysis of the outcomes, disease control, and toxicity of high-dose-rate (HDR) brachytherapy used as the only treatment modality (monotherapy) for localized prostate cancer. METHODS: Between 2006 and 2012, 77 patients with diagnosed prostate cancer were treated with HDR brachytherapy as a monotherapy. The prescribed dose was 45 Gy in three separate implants 21 days apart, with single fraction per implant. Of the 77 patients, 67 (87%) received hormonal therapy. Prostate-specific antigen failure was defined according to Phoenix consensus, as nadir + 2 ng/mL. Toxicity was scored according to Common Terminology Criteria for Adverse Events, version 4.03. RESULTS: The median followup time was 57 months (4.75 years). The 5-year actuarial overall survival was 98.7%, biochemical control 96.7%, local control 96.9%, and metastasis-free survival 98.4%. Younger age at the beginning of brachytherapy predicted the onset of bounce phenomenon. There were no Grade 3 or higher acute toxicities detected, and Grade 2 genitourinary acute toxicity developed in 19 patients (24.6%). There were no Grade 2 gastrointestinal complications. No Grade 4 or 5 late toxicity was detected. There were also no Grade 3 gastrointestinal toxicities detected. One patient (1.3%) underwent transurethral resection of the prostate because of Grade 3 urethral stenosis and urinary retention. A total of 26 patients (33.8%) developed Grade 2 late toxicity. CONCLUSIONS: HDR brachytherapy as monotherapy for localized prostate cancer was feasible, effective, and had acceptable toxicity profile.