ESTRO 2024 - Abstract Book

S2407

Clinical - Urology

ESTRO 2024

Purpose/Objective:

Stereotactic Body Radiotherapy (SBRT) is extensively applied in the treatment of localized prostate cancer, yet there remains a debate over the optimal dosage. This study aims to compare the safety and efficacy of high-dose biologically effective dose (BED) and standard-dose regimens in SBRT for localized prostate cancer through retrospective data from two cancer institutions using propensity score matching (PSM) analysis.

Material/Methods:

Patients receiving prostate-localized SBRT from two research centers were selected between June 2012 and February 2022, excluding cases with prior radical surgery, brachytherapy, or proton therapy. The experimental group included 12 patients defined by a high-dose BED 1.5 (α/β=1.5Gy) exceeding 250Gy, while the control group comprised 119 patients adhering to the NCCN guideline-recommended dose range of (35-37.5 Gy/5f) with BED 1.5 198.3-225Gy. For the low-risk prostate cancer cohort, the Clinical Target Volume (CTV) encompassed the entire prostate. In the intermediate-risk group, the CTV included the entire prostate and a 1-centimeter margin around the seminal vesicles. For the high-risk and very high-risk groups, the CTV comprised the entire prostate and a 2 centimeter margin around the seminal vesicles. SBRT was administered using CyberKnife (Accuray Corporation, Sunnyvale, CA, USA). PSM was employed to eliminate confounding variables, considering prognostic scores, Gleason pathological grading, TNM staging, age, and prostate-specific antigen (PSA) levels. The R4.3.1 software was used for 1:4 nearest neighbor matching, resulting in 12*4 matched samples. Kaplan-Meier method analysis was conducted using SPSS version 26 to assess differences in survival rates, biochemical progression-free survival (bPFS), local control (LC)and distant metastasis-free survival (DMFS). Log-rank tests were used to compare different treatment groups. Significant differences between categorical and continuous variables were detected using Chi-square and Student's t-test. All tests were two-sided, with a significance level set at P<0.05.

Results: