Two implant-fraction HDR-brachytherapy for prostate cancer: preliminary results and early toxicity
PO-2195
Abstract
Two implant-fraction HDR-brachytherapy for prostate cancer: preliminary results and early toxicity
Authors: Iosif Strouthos1,3, Konstantinos Ferentinos1,3, Efstratios Karagiannis1,3, Georgios Antorkas2, Anna Antoniou2, Yiannis Roussakis2, Nicole Zamba1, Elizabeth Georgiou1
1German Oncology Center, Department of Radiation Oncology, Limassol, Cyprus; 2German Oncology Center, Department of Medical Physics, Limassol, Cyprus; 3European University Cyprus, Faculty of Medicine, Nicosia, Cyprus
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Purpose or Objective
To analyse preliminary results in regard to early toxicity and urinary symptomatology of a two-implant-fraction high dose rate (HDR) brachytherapy (BRT) protocol used as monotherapy for clinically localised prostate cancer.
Material and Methods
A retrospective analysis was conducted on 65 patients previously treated with HDR brachytherapy for prostate between April 2020 and April 2022. Patients received two fractions of 14 Gy, volume up to a total physical dose of 28 Gy with 7 days being the interfractional interval. The procedure was carried out using a transperineal approach and transrectal ultrasound-guided planning with fusion of MRI imaging acquired at the day of the procedure. Acute toxicity was evaluated both in regard to genitourinary and gastrointestinal systems using Radiation Oncology Therapy Group/European Organization for Research and Treatment of Cancer (RTOG/EORTC) grading and urinary symptomatology with International Prostate System Score (IPSS).
Results
The mean age was 69 (range: 49-81) years. The cohort comprised of 24 (37%) low, 35 (54%) favourable intermediate, 5 (8%) unfavourable intermediate and one (2%) high risk stratified according to National Comprehensive Cancer Network guidelines (NCCN). Androgen deprivation therapy duration was administered accordingly, based on risk group, with a total of 4 patients receiving ADT. A mean iPSA of 7.80 ng/ml (range: 1.50 - 21.0 ng/ml) and a mean prostate volume of 46.2 cubic centimeters [range: 22.4 - 99.3 (cc)] were also reported. In regard to early acute GU toxicity, 5% grade 2 and 2% grade 3 was noted at 3 months. No grade 2 or 3 acute GI toxicity was observed. Based on IPSS score, 15 patients (24%) experienced a worsening of the urinary symptomatology compared to baseline, with 38% of patients experiencing mild, 54% moderate, and 8% severe symptoms.
Conclusion
Our preliminary findings further support the use of HDR BRT as monotherapy for clinically organ-confined prostate adenocarcinoma and indicate that this radiotherapeutic protocol is accompanied with a favourable early toxicity profile.