Background  Abdominal and pelvic lymph node metastasis is an important factor in evaluating the prognosis of patients with endometrial cancer (EC). Systematic lymphadenectomy (pelvic and para-aortic lymphadenectomy) for patients with endometrial cancer is an important part of staging surgery, which can not only define staging, guide further treatment, but also assess prognosis. However, due to the risk of surgery and the impact on the postoperative quality of life, the extent of lymph node dissection is still controversial.

  Objective  To compare the effect of systematic pelvic and para-aortic lymph node dissection versus simple pelvic lymph node dissection on the survival outcome of patients with endometrial cancer.

  Methods  This paper met the requirements of meta-analysis for intervention studies in PRISMA guidelines. The retrieval databases included PubMed, Embase, Medline, CNKI, VIP and Wanfang journals. Search terms were pelvic, para-aortic, lymphadenectomy, endometrial cancer and prognosis. The search period was up to January 2021. Patients included in the study were initially treated for endometrial cancer confirmed by endometrial biopsy. They all underwent standard surgical treatment (whole uterus+double adnexectomy+pelvic lymph node cleaning±para-aortic lymph node cleaning). The observation group was EC patients who underwent systematic pelvic and para-aortic lymph node dissection, and patients in the control group only underwent pelvic lymph node dissection. The primary outcome indexes included 3-year overall survival and 3-year recurrence rate, and the secondary indexes were operation time, blood loss, lymph nodes dissection and postoperative complications. Review Manager 5.3 software was used to analyze and compare the differences in intraoperative conditions and survival outcome between the two groups.

  Results  Totally 2 409 EC patients were included in 17 retrospective studies. There was no significant difference in age, tumor stage or type between the two groups. The observation group had higher 3-year OS (96%) and lower 3-year recurrence rate (65%) than those of the control group (OS, OR:1.96, 95%CI 1.44-2.67; recurrence, OR: 0.35, 95%CI 0.26-0.48). However, the operation time was prolonged (P<0.01). There was no significant difference in blood loss (P=0.09) or postoperative complications (P=0.26) between the observation group and the control group.

  Conclusion  Patients with endometrial cancer undergoing pelvic and para-aortic lymph node dissection have better survival outcome, lower recurrence rate, and no significant increases in intraoperative blood loss or surgical complications are found when compared with those undergoing pelvic lymph node dissection alone.