Salvage low-dose-rate brachytherapy for locally recurrent prostate cancer after definitive irradiation

Y Meraouna; P Blanchard; S Losa; A Labib; S Krhili; P Pommier; G Crehange; T Flam; J-M Cosset; M Kissel

doi:10.1016/j.ctro.2024.100809

Salvage low-dose-rate brachytherapy for locally recurrent prostate cancer after definitive irradiation

Clin Transl Radiat Oncol. 2024 Jun 22:48:100809. doi: 10.1016/j.ctro.2024.100809. eCollection 2024 Sep.

Authors

Y Meraouna^{1

2}, P Blanchard³, S Losa⁴, A Labib¹, S Krhili¹, P Pommier¹, G Crehange¹, T Flam^{1

5}, J-M Cosset⁶, M Kissel¹

Affiliations

¹ Radiotherapy Department, Institut Curie, 26 rue d'Ulm, 75005 Paris, France.
² Faculté de médecine Sorbonne Université, 91-105 Boulevard de l'Hôpital, 75013 Paris, France.
³ Radiotherapy Department, Gustave Roussy, 114 Boulevard Edouard Vaillant, 94220 Villejuif, France.
⁴ Physics Department, Institut Curie, 26 rue d'Ulm, 75005 Paris, France.
⁵ Urology Department, Clinique Saint Jean de Dieu, 2 rue Rousselet, 75007 Paris, France.
⁶ Radiotherapy Department, Centre Charlebourg - La Défense - Amethyst Radiothérapie, 65 Avenue Foch, 92250 La Garenne-Colombes, France.

Abstract

Purpose: The optimal management of locally recurrent prostate cancer after definitive irradiation is still unclear but local salvage treatments are gaining interest. A retrospective, single-institution analysis of clinical outcomes and treatment-related toxicity after salvage I-125 low-dose-rate (LDR) brachytherapy (BT) for locally-recurrent prostate cancer was conducted in a Comprehensive Cancer Center.

Patients and methods: A total of 94 patients treated with salvage LDR-BT between 2006 and 2021 were included. The target volume was either the whole-gland +/- a boost on the GTV, the hemigland, or only the GTV. The prescribed dose ranged from 90 to 145 Gy. Toxicity was graded by Common Terminology Criteria for Adverse Events (CTCAE) v5.0.

Results: Median follow-up was 34 months. Initial radiotherapy was external beam radiotherapy in 73 patients (78 %) with a median dose of 76 Gy and I-125 BT in 21 patients (22 %) with a prescribed dose of 145 Gy. Median PSA at salvage was 3.75 ng/ml with a median interval between first and salvage irradiation of 9.4 years. Salvage brachytherapy was associated with androgen deprivation therapy for 32 % of the patients. Only 4 % of the patients were castrate-resistant. Failure free survival was 82 % at 2 years and 66 % at 3 years. The only factors associated with failure-free survival on multivariate analysis were hormonosensitivity at relapse and European Association of Urology (EAU) prognostic group. Late grade 3 urinary and rectal toxicities occurred in 12 % and 1 % of the patients respectively.No significant difference in toxicity or efficacy was observed between the three implant volume groups.

Conclusion: The efficacy and toxicity results are consistent with those in the LDR group of the MASTER meta-analysis. Salvage BT confirms to be an effective and safe option for locally recurrent prostate cancer. A focal approach could be interesting to reduce late severe toxicities, especially urinary.

Keywords: Brachytherapy; Disease-free-survival; Low dose rate; Prostatic neoplasms; Re-irradiation; Salvage Therapy.