Survival benefits of para-aortic lymphadenectomy in colorectal cancer with clinically suspected para-aortic lymph node metastasis: a meta-analysis and systematic review

Abstract

Background and objectives: In patients with colorectal cancer and clinically suspected para-aortic lymph node metastasis, the survival benefit of para-aortic lymphadenectomy is unknown. We conducted a meta-analysis and systematic review to investigate it.

Methods: PubMed, Web of Science, and EMBASE were searched until January 2000 to April 2022 to identify studies reporting overall survivals, complication rates, and hazard ratios of prognostic factors in patients with colorectal cancer undergoing para-aortic lymphadenectomy, and those data were pooled.

Results: Twenty retrospective studies (1021 patients undergoing para-aortic lymphadenectomy) met the inclusion criteria. Meta-analysis indicates that participants undergoing para-aortic lymphadenectomy were associated with 5-year survival benefit, compared to those not receiving para-aortic lymphadenectomy (odds ratio = 3.73, 95% confidence interval: 2.05-6.78), but there was no significant difference in complication rate (odds ratio = 0.97, 95% confidence interval: 0.46-2.08). Further analysis of para-aortic lymphadenectomy group showed that 5-year survival of the positive group with pathologically para-aortic lymph node metastasis was lower than that of the negative group (odds ratio = 0.19, 95% confidence interval: 0.11-0.31). Moreover, complete resection (odds ratio = 5.26, 95% confidence interval: 2.02-13.69), para-aortic lymph node metastasis (≤4) (hazard ratio = 1.88, 95% confidence interval: 0.97-3.62), and medium-high differentiation (hazard ratio = 2.98, 95% confidence interval: 1.48-5.99) were protective factors for survival. Preoperative extra-retroperitoneal metastasis was associated with poorer relapse-free survival (hazard ratio = 1.85, 95% confidence interval: 1.10-3.10).

Conclusion: Para-aortic lymphadenectomy had promising clinical efficacy in prolonging survival rather than complication rate in patients with colorectal cancer and clinically diagnostic para-aortic lymph node metastasis. Further prospective studies should be performed.

Trial registration: PROSPERO: CRD42022379276.

Keywords: Colorectal cancer; Metastasis; Para-aortic lymph node; Para-aortic lymphadenectomy; Survival.