The value of lymphadenectomy in surgical resection of perihilar cholangiocarcinoma: a systematic review and meta-analysis.

Surgical resection is the only potentially curative treatment for patients with resectable perihilar cholangiocarcinoma (PHC). There is still no consensus on the value of lymphadenectomy despite evidence indicating lymph node (LN) status is an important prognostic indicator for postoperative long-term survival. We sought to perform a meta-analysis to summarize the current evidence on the value of lymphadenectomy among patients undergoing surgery for PHC. The PubMed (OvidSP), Embase and Cochrane Library were systematically searched for studies published before July 2020 that reported on lymphadenectomy at the time of surgery for PHC after curative surgery. 7748 patients from 28 studies were included in the meta-analysis. No survival benefit was identified with increased number of LN resected (all P > 0.05). Meanwhile, overall LN status was an important prognostic factor. Patients with lymph node metastasis had a pooled estimate hazard ratio of death that was over two-fold higher than patients without lymph node metastasis (HR 2.07, 95% CI 1.65-2.59, P < 0.001). The examination of 5 LNs on histology was associated with better staging of lymph node status and stratification of patients into positive or negative LN groups. While the extent of LN dissection was not associated with a survival benefit, examination of more than 5 LNs better staged patients into positive or negative LN groups with a lower risk of nodal understaging.