ESTRO 2024 - Abstract Book

S415

Brachytherapy - Urology

ESTRO 2024

Michael Pinkawa 1 , Susanne Temming 1 , Ali Rashid 1 , Albert Heidrich 2 , Andreas Schäfer 3 , Attila Kovács 3 , Horst Hernmani 1 1 Robert Janker Klinik, Radiation Oncology, Bonn, Germany. 2 Robert Janker Klinik, Urology, Bonn, Germany. 3 Robert Janker Klinik, Interventional and Diagnostic Radiology, Bonn, Germany

Purpose/Objective:

Spacers are increasingly applied for primary prostate cancer radiotherapy. There is limited experience in using spacers in recurrent cancer. The purpose of this study was to evaluate the feasibility of focal hyaluronic spacer injection before focal high-dose-rate brachytherapy (BT).

Material/Methods:

Hyaluronic acid was injected under transrectal ultrasound guidance in 12 consecutive patients who presented with a local recurrence after primary radiotherapy or operation to decrease the dose to the rectum and – if possible - bladder. The resulting distance between the recurrence and rectal wall, dose distribution and procedure related/acute treatment related toxicity were evaluated.

Results:

The primary tumour was prostate cancer in 11 patients, cervical cancer in one patient. Initial treatment was an operation in 6 patients and radiotherapy in 6 patients. The recurrence localization seminal vesicle/seminal vesicle fossa in 5 patients, bladder wall in 4 patients, prostate in 2 patients and cervix in one patient. Re-treatment was BT as monotherapy in 6 patients, combined external beam radiotherapy (EBRT) with BT in 4 patients and stereotactic radiotherapy in 2 patients (who refused brachytherapy). Interstitial BT was applied in 1-3 fractions, using 10-15Gy fraction doses to the recurrence. A volume of 3-12ml (mean 9ml) was injected, as hyaluronic acid was available in 3ml syringes. The injection resulted in a spacer extension of 2.9(+/-1.0, standard deviation) cm, 1.4(+/-0.5) cm and 3.5(+/-1.0) in lateral, anterior-posterior and superior-inferior directions. Examples in patients with local recurrences in the cervix and seminal vesicle fossa are presented in Fig. 1 und Fig. 2, respectively.