The prognostic value of the primary tumor's nodal status after surgery for colorectal liver metastases in the era of effective systemic therapy.

BACKGROUND: The nodal status of primary colorectal cancer is of prognostic value for survival after the resection for colorectal liver metastases (CRLM). However, in the past decade,effective adjuvant chemotherapy for lymph node positive primary colon cancer was introduced. This study evaluated the prognostic value of primary lymph node status in patients with resectable metachronous CRLM in the era of effective systemic therapy. METHODS: Between January 2000 and December 2011, all consecutive patients undergoing curative liver resection for CRLM were retrospectively analyzed. Overall survival (OS) was analyzed by the localization of the primary tumor (colon vs. rectum) and by lymph node status (positive vs. negative) of the primary tumor. RESULTS: A total of 286 patients with metachronous CRLM's were selected. Five-year OS was similar for colon and rectal primaries (42 and 40%, p = 0.62). Lymph node positivity was only a prognostic factor in rectal primaries (N+ 32% vs. N0 49%, p = 0.04) and not in colon primaries (N+ 42% vs. N0 41%, p = 0.99). In multivariate analysis, these results were confirmed. CONCLUSION: The current study demonstrates that the nodal status of primary colon malignancies does not have prognostic value in patients undergoing resection for metachronous CRLM. A possible explanation might be the administration of effective adjuvant chemotherapy in node positive colon cancer.