Salvage I-125 brachytherapy for locally-recurrent prostate cancer after radiotherapy

O Pons-Llanas; J Burgos-Burgos; S Roldan-Ortega; A Conde-Moreno; F Celada-Alvarez; J C Ruiz-Martinez; F Lliso-Valverde; A Tormo-Micó; J Perez-Calatayud; J López-Torrecilla

doi:10.1016/j.rpor.2020.06.010

Salvage I-125 brachytherapy for locally-recurrent prostate cancer after radiotherapy

Rep Pract Oncol Radiother. 2020 Sep-Oct;25(5):754-759. doi: 10.1016/j.rpor.2020.06.010. Epub 2020 Jul 5.

Affiliations

¹ Radiotherapy Department, La Fe University and Polytechnic Hospital, Valencia Spain.
² Radiotherapy Department, Hospital, Las Palmas de Gran Canaria, Spain.
³ Radiotherapy Department, General University Hospital, Valencia, Spain.

Abstract

Purpose: Retrospective, single-institution analysis of clinical outcomes and treatment-related toxicity in patients treated with salvage I-125 low-dose rate (LDR) brachytherapy (BT) for locally-recurrent prostate cancer after radiotherapy.

Materials and methods: Between 2008 and 2018, 30 patients with biopsy-confirmed prostate cancer recurrence underwent salvage treatment with I-125 LDR-BT. Of these 30 patients, 14 were previously treated with primary external beam radiotherapy (EBRT; median dose, 73 Gy) and 16 with primary I-125 LDR-BT (145 Gy and 160 Gy in 14 and 2 cases, respectively). At seed implantation, the mean age was 75.8 years, with a median Gleason score of 7 and pre-salvage PSA of <10 ng/mL. Six patients received androgen deprivation therapy for six months after relapse diagnosis. The prescribed salvage I-125 BT dose to the gland was 120-130 Gy, with dose restrictions of Dmax <135% (urethra) and <100% (rectum). Toxicity was evaluated according to the CTCAE scale (v4.0).

Results: At a median follow-up of 45 months, the biochemical recurrence-free survival rates at 1, 3 and 5 years were 86.7%, 56.7% and 53.3%, respectively. Overall survival at 5 years was 87%. On the multivariate analysis, two variables were significant predictors of recurrence: PSA at relapse and nadir PSA post-salvage. Grade 3 genitourinary toxicity was observed in 5 patients (radiation-induced cystitis in 3 cases and urethral stenosis in 2) and G3 gastrointestinal toxicity in 3 patients (rectal bleeding).

Conclusion: Salvage therapy with I-125 brachytherapy is a safe and effective treatment option for locally-recurrent prostate cancer in previously-irradiated patients. High pre-salvage PSA and post-salvage nadir PSA values were significantly associated with a worse disease control after salvage I-125 LDR-BT. In well-selected patients, I-125 LDR-BT is comparable to other salvage therapies in terms of disease control and toxicity. However, more research is needed to determine the optimal management of locally-recurrent prostate cancer.

Keywords: Permanent seed I-125 implant; Prostate cancer; Salvage brachytherapy.