ESTRO 2024 - Abstract Book

S2581

Clinical - Urology

ESTRO 2024

42.4% patients were metastatic at diagnosis and 30.3% were IMDC (International Metastatic RCC Database Consortium risk score) with good prognosis, 57.6% were intermediate and 12.1% poor. 84.9% of patients underwent SBRT at baseline or in the course of systemic treatment. Most irradiated metastases sites were bone (78.8%) and lung (12.1%). We found 78.8% of EFS at 6 months and 54.5% at one year after SBRT. There were no differences in LC between the irradiated lesion, bone (78.8%) or extraosseous (71.4%) (p:0.59). A 15.16% of the patients who performed SBRT exclusively, maintained TFST, with a minimum follow-up of 9.1 months. A non-significant trend was observed between the number of treatment lines performed (EFS ≥ 3 lines: 19.2% No EFS ≥3 lines: 71.4% p:0.11) and the absence of EFS. The OS at 1 year after SBRT was 66.6%. Median TTNT was 480.2 days (15.8 months) and TTNT ≥6 months was achieved in 78.8% of our patients. No grade 3 toxicities were reported.

Conclusion:

SBRT in RCC contributes to the deferral of systemic therapy in oligometastatic patients, and helps to maintain line of treatment in metastatic patients with oligoprogression, with a 50% EFS one year after SBRT. There were no differences with the irradiated metastatic location. Prospective studies are needed to evaluate the benefit of SBRT.

Keywords: SBRT, RENAL CELL CARCINOMA

2881

Digital Poster

SBRT with MRI-defined boost for prostate cancer: results from a prospective observational study

Marco Galaverni, Federico Colombo, Francesco Salaroli, Claudia Grondelli, Ilaria Renna, Stella Gianni, Elisabetta Lattanzi, Giovanni Ceccon, Cristina Dell'Anna, Maria Luisa Bergamini, Nunziata D'Abbiero, Nicola Simoni

Azienda Ospedaliero-Universitaria di Parma, Radiation Oncology Unit, Parma, Italy

Purpose/Objective:

After prostate Stereotactic Body Radiotherapy (SBRT), local recurrence typically occurs in the pre-treatment multiparametric magnetic resonance imaging (mpMRI) region of a PI-RADS 4 or 5 dominant intra-prostatic lesion (DIL) [1]. The addition of a focal boost to the DIL is an emerging strategy to potentially improve tumor control in patients with organ-confined Prostate Cancer (PCa) [2, 3]. This study aimed to report early acute toxicity and dosimetry results of a prospective observational study of prostate SBRT with a Simultaneous Integrated Boost (SIB) to the mpMRI/targeted biopsy-defined focal lesions.

Material/Methods:

Patients with newly diagnosed organ-confined PCa with clinical stage T1- T2c adenocarcinoma, Gleason score ≤8, prostate- specific antigen (PSA) value <20 ng/mL, and prostate volume ≤ 90 cc were included in the study. The presence of DIL on mpMRI, confirmed on targeted US-fusion biopsy, was mandatory for inclusion in the study and