Long-term oncological and functional follow-up in low-dose-rate brachytherapy for prostate cancer: results from the prospective nationwide Swiss registry
Journal Paper/Review - Feb 12, 2020
Viktorin-Baier Pascal, Putora Paul Martin, Schmid Hans-Peter, Plasswilm Ludwig, Schwab Christoph, Thoeni Armin, Hochreiter Werner, Prikler Ladislav, Suter Stefan, Stucki Patrick, Müntener Michael, Blick Nadja, Schiefer Hans, Güsewell Sabine, Zürn Karin, Engeler Daniel Stephan
To evaluate the long-term oncological, functional and toxicity outcomes of low-dose-rate brachytherapy (LDR-BT) in relation to risk factors and radiation dose in a prospective multicentre cohort.
PATIENTS AND METHODS
Data of patients from 12 Swiss centres undergoing LDR-BT from September 2004 to March 2018 were prospectively collected. Patients with a follow-up of ≥3 months were analysed. Functional and oncological outcomes were assessed at ~6 weeks, 6 and 12 months after implantation and annually thereafter. LDR-BT was performed with I seeds. Dosimetry was done 6 weeks after implantation based on the European Society for Radiotherapy and Oncology recommendations. The Kaplan-Meier method was used for biochemical recurrence-free survival (BRFS). A prostate-specific antigen (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. The median (range) follow-up was 37.1 (3.0-141.6) months. Better BRFS was found for Gleason score ≤3+4 (P = 0.03, log-rank test) and initial PSA level of <10 ng/mL (P < 0.001). D'Amico Risk groups were significantly associated with BRFS (P < 0.001), with a hazard ratio of 2.38 for intermediate- and high-risk patients vs low-risk patients. The radiation dose covering 90% of the prostate volume (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.