ESTRO meets Asia 2024 - Abstract Book

S296

Interdisciplinary – Urology

ESTRO meets Asia 2024

Material/Methods:

Between August 2022 and June 2023, two patients with isolated clinical/radiological local progression in the kidney, confirmed by biopsy and FDG PET-CT, received SBRT. The age of patients was 64 and 60 year-old. The first patient was initially treated by the immuno-chemotherapy with carboplatin-pemetrexed-pembrolizumab, followed by pembrolizumab maintenance. The second patient had a first line EGFR-targeted therapy by osimertinib, and at the time of progression a new endobronchial ultrasound biopsy showed a small cell neuroendocrine carcinoma transformation, treated by carboplatin-etoposide. Due to persistent right kidney metastasis, as confirmed by biopsy and after institutional Tumorboard decision, SBRT directed to the isolated kidney metastasis using the MR-Linac was offered. Dosimetric goals respecting organ at risk dose constraints were achieved. The SBRT plan was computed with the Monaco treatment planning system. We reported dosimetric parameters, acute and chronic toxicity according to CTCAE v 5.0.

Results:

A total dose of 40 Gy was delivered in 5 fractions to the isolated kidney metastasis volume in both patients. Four dimensional CT scanning was used for treatment planning to account for respiratory motion. Treatment was delivered using the MR-Linac with daily dosimetric readaptation based on daily MRI imaging and real-time MRI motion monitoring. Neither patient experienced gastrointestinal (GI) or genitourinary (GU) acute or chronic toxicity, evaluated at twenty and six months following SBRT, for patient 1 and 2, respectively. Renal function, as assessed by estimated glomerular filtration rate (eGFR) and serum creatinine level, remained unchanged after SBRT.

Conclusion:

While other local treatments such as cryoablation (CA) or radiofrequency ablation (RFA) exist, SBRT, particularly when using the MR-Linac, is an emerging noninvasive option that provides high-precision radiotherapy requiring few outpatient visits. It represents a safe and effective management option for isolated renal metastasis.

Keywords: Kidney, SBRT, MRILinac, oligometastases.