Purpose: Until now, most long-term results for brachytherapy only has been published for low-dose-rate (LDR) seeds. Due to radiobiology reasons, high-dose-rate (HDR) mono-brachytherapy is of growing interest. The aim of the study was to report long-term biochemical control rate and toxicities with HDR monotherapy.Material and methods: This was a retrospective single-institution experience, including 229 men, clinically staged T1c-T2b, Gleason 3 + 3 (prostate specific antigen (PSA) ≤ 15), or Gleason 3 + 4 (PSA ≤ 10), consecutively treated between 2004 and 2012 with HDR brachytherapy alone, using three different fractionation schedules of 92-95 Gy (EQD(2), α/β = 3). Group 4F (n = 19) had a single implant of 9.5 Gy in four fractions over 2 days. Group 3F (n = 107) had three separate implants of 11 Gy over 4 weeks. Group 2F (n = 103) had two implants of 14 Gy over 2 weeks. No adjuvant hormonal therapy was allowed.Results: For 4F, 3F, and 2F study groups, median follow-up was 10.2, 7.1, and 6.1 years, respectively, and biochemical failure rate was 10.5%, 4.7%, and 14.6%, respectively. Early and late side effects were followed with common terminology criteria version 2.0 and patient-reported questionnaires. There were a temporary acute urethral toxicity increase, 1-2 grades over baseline lower urinary tract symptoms (LUTS), which usually recovered. About 1/3 of the patients had a remaining one grade over baseline LUTS. Severe grade 3-4 toxicity were only found in 3.5% of patients. No rectal toxicity was observed. Erectile dysfunction (ED) was depending on age and erectile function before treatment. In patients without ED before the treatment, we found a complete ED in 21% of men at the last follow-up.Conclusions: In the present study, HDR mono-brachytherapy was found to be an effective treatment, with mild long-term side effects difficult to differentiate from aging effects. There were no significant differences in PSA regression, PSA failure rate, and toxicity between the different fraction schedules.

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Purpose: Treating localized prostate cancer (PC) with combination radiotherapy consisting of external beam radiotherapy (EBRT) and high-dose-rate brachytherapy (HDR-BT) has been proven to result in better disease outcome than EBRT only. We aimed to evaluate the incidence of toxicities due to combination therapy and identify parameters correlated to acute or late urinary, rectal, and erectile toxicities.Material and methods: Data on symptoms and tumor/treatment parameters were collected from 359 patients treated between 2008 and 2018 with EBRT (42 Gy in 14 fractions) and HDR-BT (14.5 Gy in one fraction) for localized PC, at the Örebro University Hospital. Urinary, rectal, and erectile symptoms were presented descriptively, and bivariate analyses for correlation between grade ≥ 2 toxicity and potential predictors were performed. To evaluate prognostic models, multivariable analyses were applied.Results: Urinary toxicity grade ≥ 2 was observed in 154 patients (47% of patients without pre-existing symptoms grade ≥ 2), of which 15 were grade 3. Rectal toxicity grade 2 was observed in 22 (6%) patients. Any grade erectile dysfunction was evident in all patients without pre-existing dysfunction (n = 103), whereas only 7 recovered completely. In bivariate analyses age was correlated with higher risk of acute urinary toxicity, and irradiated volume was associated with both urinary and rectal toxicities. However, we found no multivariable model of clinical and statistical significance to predict the risk of urinary or rectal toxicities.Conclusions: In our study cohort, the severity of toxicities was in general mild or moderate and temporary, whereas the incidence of severe toxicity was considerably low. Although we found no predictive models for toxicities, our findings are reassuring that this treatment approach as curative therapy for localized PC is well-tolerated.