ESTRO 2024 - Abstract Book

S2421

Clinical - Urology

ESTRO 2024

1302

Poster Discussion

From Blade To Beam: Unsheathing The Sabr After Prostatectomy

Angel Montero 1 , Ovidio Hernando 1 , Mercedes López 1 , Jeannette Valero 1 , Raquel Ciérvide 1 , Xin Chen-Zhao 1 , Beatriz Alvarez 1 , Miguel-Angel de la Casa 2 , Mariola García-Aranda 1 , Emilio Sánchez 1 , Carmen Cañadillas 1 , Rosa Alonso 1 , Juan García 2 , Carmen Saiz 1 , Pedro Fernández-Letón 2 , Carmen Rubio 1

1 HM Hospitales, Radiation Oncology, Madrid, Spain. 2 HM Hospitales, Medical Physics, Madrid, Spain

Purpose/Objective:

Post-prostatectomy radiotherapy contributes to improved prognosis in prostate cancer patients experiencing recurrence after surgery or presenting risk factors for relapse. We present preliminary tolerance results of an ultra hypofractionated SABR regimen, which offers an attractive option for these patients.

Material/Methods:

Between April 2019 and April 2023, 100 men (median age: 68 years, range: 47-82) underwent post-prostatectomy SABR. Adjuvant radiation therapy (ART) was administered to 40 high-risk patients (detectable post-surgery PSA, Grade Group 4/5, nodal involvement), while salvage radiotherapy (SRT) was delivered to 60 patients with rising PSA levels post-undetectable values (<0.1 ng/mL). Volumetric Modulated Arc Therapy (VMAT) delivered a total dose of 36.25 Gy in 5 fractions (7.25 Gy/fraction) on alternate days, targeting the surgical bed per RTOG guidelines. Urethra sparing protocol reduced the prescribed dose per fraction to the urethra and adjacent zone from 7.25 Gy to 6.5 Gy. Elective nodal irradiation was performed in 57 patients (cumulative dose: 26 Gy in 5 fractions, 5.2 Gy/fraction), with 11 additional patients receiving a simultaneous integrated boost (total dose: 40 Gy in 5 fractions) for pelvic nodal disease. Twenty-four high-risk patients underwent 24-month androgen deprivation therapy (ADT).

Results:

After surgery, baseline assessment showed varying urinary and sexual function levels: 31 patients maintained continence, while 27 had mild, 27 moderate, and 15 severe urinary incontinence. Seventeen retained sexual function, while 20, 19, and 44 experienced mild, moderate, or severe erectile dysfunction. Treatment was well tolerated with minimal toxicity. With a median 15-month follow-up (3-47 months), all patients remained alive and under observation. Acute and early-late complications reached a maximum grade 2, impacting 2, 6, 2, and 5 patients in genitourinary and gastrointestinal areas respectively. No grade 3 or higher toxicity was seen acutely or during follow-up.