To evaluate the long‐term oncological, functional and toxicity outcomes of LDR‐BT in relation to risk factors and radiation dose in a prospective multicenter cohort.
Patients and Methods
Data of patients from 12 Swiss centers undergoing LDR‐BT from 09/2004 ‐ 03/2018 were prospectively collected. Patients with a follow‐up ≥ 3 months were analyzed. Functional and oncologic outcomes were assessed at approximately 6 weeks, 6 and 12 months post‐implantation and annually thereafter. LDR‐BT was performed with 125‐Iodine seeds. Dosimetry was done 6 weeks after implantation based on the European Society for Radiotherapy and Oncology recommendations. Kaplan‐Meier method was used for biochemical recurrence free survival (BRFS). A PSA rise above the PSA nadir + 2 was defined as biochemical failure. Functional outcomes were assessed by urodynamic measurement parameters and questionnaires.
Of 1580 patients in the database, 1291 (81.7%) were evaluable for therapy outcome. Median follow up was 37.1 months (range 3.0 – 141.6). Better BRFS was found for Gleason score ≤ 3+4 (p=0.03, log rank test) and initial PSA level of < 10ng/ml (p<0.001). D’Amico Risk groups were significantly associated with BRFS (p<0.001), with a hazard ratio (HR) of 2.38 for intermediate and high‐risk patients vs low risk patients. D90 after 6 weeks was significantly lower in patients with recurrence. Functional outcomes returned close to baseline levels after 2‐3 years. A major limitation of these findings is a substantial loss to follow‐up.
Our results are in line with other studies showing that LDR‐BT is associated with good oncological outcomes together with good functional results.