Contralateral pelvic lymph node metastases in patients with unilateral early-stage epithelial ovarian cancer: a systematic review and meta-analysis.

Objective: This systematic review and meta-analysis aimed to assess the rate of contralateral pelvic lymph node metastases in macroscopically unilateral early-stage epithelial ovarian cancer.

Methods: A systematic literature review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist, and the protocol was registered in PROSPERO (CRD42024513857). MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials were searched from inception until June 2024. The inclusion criteria were studies involving patients with macroscopically unilateral early-stage (International Federation of Gynecology and Obstetrics stage I-II) epithelial ovarian cancer with surgical staging.

Results: Ten studies met the inclusion criteria. All studies were observational; 9 were retrospective and 1 was prospective, including a total of 668 patients. The pooled rate of isolated contralateral pelvic lymph node metastases was 0.9% (95% CI 0.1 to 2.3, I² = 24.6%, 4 studies; 391 participants; 5 events). The pooled rate of contralateral (isolated or bilateral) pelvic lymph node metastases was 1.9% (95% CI 0.1 to 5.2, I² = 57.3%, 4 studies; 391 participants; 7 events). The overall pooled rate of lymph node metastases was 10.8% (95% CI 8.4 to 13.5, I² = 0%, 7 studies; 605 participants; 68 events). The rate of microscopic contralateral ovarian disease was reported in 3 studies, at 3.5%.

Conclusions: The rate of isolated contralateral pelvic lymph node metastases in macroscopically unilateral early-stage epithelial ovarian cancer is 0.9%. Therefore, para-aortic and ipsilateral pelvic and lymph node dissection may be adequate in cases of macroscopically unilateral ovarian disease. However, given the limited evidence, these findings must be interpreted with caution.