Oral and Poster Presentation – Clinical Abstracts Archive

UK & Ireland Prostate Brachytherapy Conference 2017

Abstract number 1

Early outcomes of 19 Gy single fraction High-dose-rate brachytherapy as monotherapy for localised prostate cancer

Challapalli A*; Masson S*; Humphrey P*; Jacobs P*; Brown A*; Bahl A*
*Bristol Cancer Institute

AIMS/INTRODUCTION: High dose rate (HDR) brachytherapy is an attractive treatment option for localised prostate cancer (CaP) utilising the radiobiological advantage of using high dose/fraction. We report the toxicity and early clinical outcomes of HDR monotherapy for low to intermediate-risk CaP.

MATERIALS/METHODS: Eighty-fi ve patients with low to intermediate-risk CaP were treated from October-2013 to February-2017. Patients had catheters placed transperineally under spinal anaesthesia, using trans-rectal ultrasound guidance. Dose delivered was 19Gy/single fraction prescribed to the prostate ± seminal vesicles base, with an isotropic 3mm margin. Toxicity was assessed using common toxicity criteria.

RESULTS: A range of volumes were implanted (20–120 cc, median: 35), using a median of 17 needles (range:13–20). Satisfactory implants were achieved in patients with volumes>60cc, by excluding pubic arch interference on the pre-implant MRI pelvis. All patients were discharged home within 24hours, with 10 patients (12%) requiring re-catheterisation. The median (range) follow-up was 16 (1-42) months. Of the 85 patients, 22% (19/85) had Gleason score 6. The median age was 71yrs (range:59-82yrs). The incidence of acute and chronic genito-urinary (GU) toxicity was Gr2: 22%&1.2%, Gr3: 17%&3.5%, respectively. Acute and chronic grade 2 gastro-intestinal (GI) toxicity was seen in 2%, but none had chronic Gr3 GI toxicity. PSA bounce was seen in 22% (12/55) predominantly between 9-18months post brachytherapy. Four patients experienced a biochemical failure, around 12-18months post treatment, giving a cumulative incidence estimate of 4.7% at
1 year. Out of these 4, 2 had salvage prostatectomy and 2 developed metastatic disease.

CONCLUSION: Our initial experience with HDR monotherapy confi rms this to be safe, with favourable and promising preliminary biochemical control rates. It is possible to implant volumes higher than 60cc, if adequate measures are taken.