PurposeTo evaluate the outcomes of high-risk prostate cancer patients treated with biologically effective dose (BED) ≥ 220 Gy of high-dose radiotherapy, using low-dose-rate (LDR) brachytherapy in combination with external beam radiotherapy (EBRT) and short-term androgen deprivation therapy (ADT).Material and methodsFrom 2005 to 2013, a total of 143 patients with high-risk prostate cancer were treated by radiotherapy of BED ≥ 220 Gy with a combination of LDR brachytherapy, EBRT, and androgen deprivation therapy (ADT). The high-risk patients in the present study included both high-risk and very high-risk prostate cancer. The number of high-risk features were: 60 patients with 1 high-risk factor (42%), 61 patients with 2 high-risk factors (43%), and 22 patients with 3 high-risk factors (15%) including five N1 disease. External beam radiotherapy fields included prostate and seminal vesicles only or whole pelvis depending on the extension of the disease. Biochemical failure was defined by the Phoenix definition.ResultsSix patients developed biochemical failure, thus providing a 5-year actual biochemical failure-free survival (BFFS) rate of 95.2%. Biochemical failure was observed exclusively in cases with distant metastasis in the present study. All six patients with biochemical relapse had clinical failure due to bone metastasis, thus yielding a 5-year freedom from clinical failure (FFCF) rate of 93.0%. None of the cases with N1 disease experienced biochemical failure. We observed four deaths, including one death from prostate cancer, therefore yielding a cause-specific survival (CSS) rate of 97.2%, and an overall survival (OS) rate of 95.5%.ConclusionsHigh-dose (BED ≥ 220 Gy) radiotherapy by LDR in combination with EBRT has shown an excellent outcome on BFFS in high-risk and very high-risk cancer, although causal relationship between BED and BFFS remain to be explained further.

Purpose: To monitor the outcomes for intermediate-risk prostate cancer patients treated with biologically effective dose (BED) ≥ 200 Gy radiotherapy using low-dose-rate (LDR) brachytherapy. Material and methods: Between 2005 and 2016, a total of 397 patients with intermediate-risk prostate cancer were treated by LDR-based radiotherapy with a BED ≥ 200 Gy. Treatments consisted of LDR brachytherapy alone (177 cases) or LDR and external beam radiotherapy (EBRT) (220 cases). Short-term androgen deprivation therapy (ADT) was used in 186 patients (46.9%). The median follow-up period was 72 months (range 29-165 months). Dosimetric parameters and BED were studied in each case. The numbers of intermediate-risk features were: 163 patients with 1 intermediate-risk feature (41%), 169 patients with 2 intermediate-risk features (43%), and 65 patients with 3 intermediate-risk features (16%). A total of 145 cases were diagnosed as having primary Gleason pattern 4: Gleason score 4 + 3 (36.5%). Results: Three patients developed biochemical failure, thus providing a 7-year actual biochemical failure-free survival (BFFS) rate of 99.1%. Biochemical failure was observed exclusively in cases with distant metastasis: two cases with lymph node metastasis and one case with bone metastasis, thus yielding a 7-year freedom from clinical failure (FFCF) rate of 99.1%. We observed eight deaths, but there was no death from prostate cancer, thus yielding a 7-year cause-specific survival (CSS) rate of 100%, and an overall survival (OS) rate of 98.4%. Conclusions: This study highlights excellent outcomes for intermediate-risk prostate cancer patients, including unfavorable intermediate-risk cases, treated with BED ≥ 200 Gy radiotherapy using LDR brachytherapy. LDR alone with a BED of 200 Gy may be an optimal treatment for both favorable and unfavorable intermediate-risk prostate cancer patients, although a longer follow-up is mandatory to confirm the present findings.