Impact of lymph node ratio on survival of colorectal cancer patients

Background and Purpose: This study analyzed the prognostic significance of the staging system based on the metastatic Node Ratio (NR) compared with the TNM staging system in patients with colorectal cancer. Methods: We reviewed the data of 444 patients who underwent colorectal resection for cancer between January 2005 and December 2011. NR categories NR0 (0%), NR1 (1-19%) and NR2 (≥20%) were determined by the best cut-off approach at log-rank test. To compare the prognostic power of the NR versus pN, we plotted these different factors against the mortality estimates. Additionally, we evaluated the relationship between these variables and the extent of lymphadenectomy. Results: Both the NR and the pN classification significantly stratified patient outcomes (p < 0.0001), but the NR system seems to better discriminate prognostic subgroups than the pN. Furthermore, NR is less dependent on the extent of lymphadenectomy than pN. Conclusions: NR is a simple and reliable tool to stratify survival of colorectal cancer patients and it seems to have a higher prognostic power than the current pN system, because it is less dependent on the extent of lymphadenectomy.