Definitive treatment for primary urethral cancer: A single institution's experience with organ-preserving brachytherapy.

Background: Radical urethectomy ± cystectomy has long represented the standard of care for rare primary urethral cancer (PUC). With our analysis, we want to demonstrate the efficacy and safety of brachytherapy (BT) of urethra for organ preservation.

Materials and methods: We analyzed treatment procedures and results of 3 patients with PUC, which have been treated in our department between 2011 and 2020 with brachytherapy. One male patient underwent brachytherapy with chemoradiotherapy after transurethral resection (TUR). Brachytherapy has been performed as high-dose-rate (HDR) boost with a cumulative dose of 8 Gy (9.3 Gy _{EQD2-α/β = 10 Gy}). The 2 further female patients have been treated with sole pulsed-dose-rate (PDR) brachytherapy with a total dose of 49.9 Gy (50.3 Gy _{EQD2-α/β = 10 Gy}) and 62.2 Gy (64.6 Gy _{EQD2-α/β = 10 Gy}).

Results: Median follow-up was 103 months (41-153). No local recurrence occurred and all patients are still alive. For the male patient we documented Grade 3 cystitis. As late side effects the pre-existing Grade 2 incontinence worsened to Grade 3. Among female patients one developed Grade 3 vaginal synechiae. There was no Grade ≥4 toxicity.

Conclusion: Brachytherapy in PUC is a feasible and promising option with high local control rate and tolerable toxicity. It provides a good alternative to surgery for organ preservation in selected patients.