3748 - Updates on Prospective Phase III Trial of Standard of Care Therapy with/without Stereotactic Ablative Radiotherapy for Recurrent Ovarian Cancer

Purpose/Objective(s): Recurrent ovarian cancer remains a major clinical challenge, with limited therapeutic options despite advances in systemic therapy. Stereotactic ablative radiotherapy (SABR) has emerged as an effective local treatment modality capable of achieving durable local control with limited toxicity in oligometastatic disease. However, prospective phase III evidence supporting the survival benefit of SABR in recurrent ovarian cancer is currently lacking. The SABR-ROC trial (KGOG 3064/KROG 2204) is an ongoing multicenter, prospective randomized phase III study designed to evaluate whether the addition of SABR to standard salvage therapy improves overall survival in patients with recurrent ovarian cancer.

Materials/Methods: Patients with pathologically confirmed epithelial ovarian cancer who experienced recurrence after completion of initial standard treatment are enrolled. Eligible patients have up to ten metastatic lesions with a maximum tumor diameter of =5 cm. Participants are randomized in a 1:2 ratio to receive either standard salvage therapy alone (control arm) or standard salvage therapy plus SABR (experimental arm). Randomization is stratified by: (1) number of favorable clinical factors—platinum sensitivity, absence of ascites, normal CA-125 level, and ECOG performance status 0–1 (0–3 vs. 4); (2) recurrence site (with vs. without lymph-node involvement); and (3) use of PARP inhibitors. SABR is delivered to selected recurrent lesions using 1 to 10 fractions, with a total dose ranging from 16 to 45 Gy according to lesion size, location, and organ-at-risk constraints. To ensure protocol adherence across participating centers, a dummy-run quality assurance process was conducted, evaluating target volume delineation, dose prescription, treatment planning consistency, and feasibility for representative clinical scenarios. In parallel, a pattern-of-care survey has been conducted among participating specialists to characterize real-world practice patterns and perceptions regarding the use of SABR in recurrent ovarian cancer. Target patient accrual (n=180) has been completed, and patients remain under prospective follow-up for the primary endpoint of overall survival. Correlative analyses and final efficacy assessments are planned after maturation of survival data. Clinical Trial number: NCT05444270.

Results: Not included in accordance with the Clinical Trials in Progress abstract guidelines.

Conclusion: Not included in accordance with the Clinical Trials in Progress abstract guidelines.