Objective <p>To evaluate the prognostic and predictive significance of supradiaphragmatic lymph node (SDLN) positivity detected by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in patients undergoing primary cytoreductive surgery for advanced epithelial ovarian cancer.</p> Methods <p>A systematic review and meta-analysis was conducted according to PRISMA 2020 guidelines and registered with PROSPERO. Studies reporting on overall survival (OS), progression-free survival (PFS), and complete cytoreduction (R0) in patients with and without 18F-FDG PET/CT-detected SDLN metastases were identified through comprehensive database searches conducted on December 18, 2024. Data from five retrospective, single-center studies comprising a total of 605 patients were included in the quantitative synthesis. Meta-analyses were performed using a random-effects model.</p> Results <p>SDLN positivity on 18F-FDG PET/CT was significantly associated with worse survival outcomes and lower resection rates. The pooled hazard ratio (HR) for OS was 1.60 (95% CI 1.19–2.25, <i>p</i> = 0.002) and for PFS 1.53 (95% CI 1.19–1.96; <i>p</i> = 0.0009), indicating poorer prognosis in SDLN-positive patients. The odds of achieving complete cytoreduction were significantly reduced in this group (OR = 0.32, 95% CI 0.15–0.68, <i>p</i> = 0.003). While heterogeneity was low for progression-free and overall survival (<i>I</i>² = 0%), moderate heterogeneity was observed in the analysis of complete cytoreduction (<i>I</i>² = 54%). None of the included studies provided histologic confirmation of 18F-FDG PET/CT-positive SDLNs.</p> Conclusions <p>18F-FDG PET/CT-detected SDLN positivity is associated with worse survival and lower resectability in advanced ovarian cancer. Due to lacking histologic confirmation and retrospective data, prospective validation is needed.</p>