S1250
Clinical - Urology
ESTRO 2026
Purpose/Objective: To report biochemical recurrence-free survival (bRFS) and incidence and severity of side effects from an observational prospective study of linear accelerator (linac)-based stereotactic body radiotherapy (SBRT) for patients with localized prostate cancer (PCa). Material/Methods: Patients with localized PCa prospectively treated with SBRT at our Institution from 2022 to 2024 were included in the analysis. SBRT was delivered with Volumetric Modulated Arc Radiotherapy (VMAT)and Flattening Filter Free (FFF) beams techniques, administering 36.25 Gy in 5 fractions every other day to the Planning Target Volume (PTV), with a simultaneous integrated boost (SIB) of 40 Gy to the prostate for intermediate and high-risk patients. Intraprostatic fiducial markers tracking was used for all patients. Biochemical recurrence was defined according to the Phoenix criteria, as an increase of ≥ 2 ng/ml above the post-SBRT PSA nadir.Genitourinary (GU) and gastrointestinal (GI) adverse events were reported using the CTCAE scoring criteria. Results: A total of 159 patients were included. Median patient age was 75 years (IQR 71-78), and median baseline PSA (iPSA) was 8.8 ng/ml (IQR 5.9-13.0). Overall, 15.7%, 64.8% and 19.5% of cases were classified as low-, intermediate, and high-risk according to D’Amico risk group, respectively. In 51.1% of patients, androgen deprivation therapy (ADT) was administered in accordance with class risk group. All patients (100%) completed the SBRT prescribed treatment, in a median time of 10 days (IQR 9-13). At a median estimated follow up of 23.7 months (95% CI 21.5-25.8), biochemical relapse occurred in 3 (1.9%) patients, with a 1-, 2- and 3-year bRFS rate of 100% (95% CI 100-100), 97.4% (95% CI 94.6-100) and 97.4% (95% CI 94.6-100), respectively (figure 1). At ≤ 3, 6, 12, 24, and 36 months from SBRT, G ≥ 2 GU adverse events were observed in 28.9%,5.7%,3.4%, 2.2% and 2.3% of patients, respectively, while G ≥ 2 GI adverse events were reported in 15.1%,1.9%,0.7%, 0.0%, and 0.0%, respectively, at the same time-point (figure 2). One (0.6%) case of G3 urethral stenosis with obstruction occurred 24 months after SBRT.At last follow up, no cancer-specific death occurred, while five (3.1%) patients had died from competing causes.
Conclusion: Prospective data confirms that 5-fraction linac-based SBRT with fiducial markers tracking for localized prostate cancer (PCa) provides favorable tumor control and tolerability. The oncological outcomes of this study align with those of randomized trials, supporting the use of SBRT as an effective treatment in daily clinical practice. Keywords: SBRT, Prostate, side effects Adjuvant radiotherapy for primary adrenocortical carcinoma (ACC): A systematic review and meta- analysis. Vasanthapriya Subramani 1 , Sreelal V 2 , Sadhana Kannan 2 , Harshdeep Chauhan 1 , Priyamvada Maitre 1 , Santosh Menon 3 , Ankit Misra 4 , Amandeep Arora 4 , Mahendra Pal 4 , Gagan Prakash 4 , Vedang Murthy 1 1 Radiation Oncology, Tata Memorial Centre, HBNI, Mumbai, India. 2 Clinical Biostatistics, Tata Memorial Centre, HBNI, Mumbai, India. 3 Pathology, Tata Digital Poster 3158
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