Routine lymphadenectomy during metastasectomy for pulmonary metastases of colorectal cancer has been recommended by several recent expert consensus meetings. However, evidence supporting lymphadenectomy is limited. The aim of this study was to perform a systematic review of the literature on the impact of simultaneous lymph node metastases on patient survival during metastasectomy for colorectal pulmonary metastases (CRPM).
A systematic review was conducted according to the PRISMA guidelines of studies on lymphadenectomy during pulmonary metastasectomy for CRPM. Articles published between 2000 and 2020 were identified from Medline, Embase and the Cochrane Library without language restriction. Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework was used to assess the risk of bias and applicability of included studies. Survival rates were assessed and compared for the presence and level of nodal involvement.
Following review of 8054 studies by paper and abstract, 27 studies comprising 3619 patients were included in the analysis. All patients included in these studies underwent lymphadenectomy during pulmonary metastasectomy for CRPM. A total of 690 patients (19.1%) had simultaneous lymph node metastases. Five-year overall survival for patients with and without lymph node metastases was 18.2% and 51.3%, respectively (p < .001). Median survival for patients with lymph node metastases was 27.9 months compared to 58.9 months in patients without lymph node metastases (p < .001). Five-year overall survival for patients with N1 and N2 lymph node metastases was 40.7% and 10.9%, respectively (p = .064).
Simultaneous lymph node metastases of CRPM have a detrimental impact on survival and this is most apparent for mediastinal lymph node metastases. Therefore, lymphadenectomy during pulmonary metastasectomy for CRPM can be advised to obtain important prognostic value.