Lymphadenectomy in ovarian cancers: a meta-analysis of hazard ratios from randomized clinical trials

Background The debate surrounding systematic lymphadenectomy in the epithelial cancers of the ovary (EOC) was temporarily put to rest by the LION trial. However, there was a glaring disparity between the number of patients registered and the number of patients randomized suggesting inadvertent selection. A subsequent meta-analysis after this trial included all types of studies in the literature (randomized, non-randomized, case series, and, retrospective cohort), thus diluting the results. Methods We conducted a meta-analysis of hazard ratios of randomized controlled trials, to study the role of systematic para-aortic and pelvic lymph node dissection in the EOC. A detailed search of MEDLINE, Cochrane, and Embase databases was done to look for the published randomized controlled trials (RCT) comparing lymphadenectomy versus no lymphadenectomy in EOC. A meta-analysis of hazard ratios (HR) was performed for overall survival (OS) and progression-free survival (PFS) using fixed and random effect models. The quality of the RCTs was evaluated on Jadad's score, and the risk of bias was estimated by the Cochrane tool. Results A total of 1342 patients with EOC were included for quantitative analysis. On meta-analysis, HR for PFS was 0.9 (95% CI 0.79-1.04) favoring lymphadenectomy. HR for OS was 1 (95% CI 0.84-1.18) signifying no benefit of systematic lymphadenectomy. Conclusion The results show a trend towards increased PFS which did not reach statistical significance nor translate into any meaningful benefit in OS. There is still a need for a greater number of well-conducted, suitably powered trials to convincingly answer this question.

Automated summary

The debate on systematic lymphadenectomy in epithelial ovarian cancers was ignited by the LION trial but remains inconclusive. Meta-analysis of randomized controlled trials showed a trend towards improved progression-free survival with lymphadenectomy, but no significant benefit on overall survival. More well-conducted trials are needed for a definitive answer.