Lymph Node Yield and Colorectal Cancer Survival: A Bowel Cancer Outcomes Registry Cohort Study.

BACKGROUND

The current standard for lymph node (LN) sampling in colorectal cancer (CRC) surgery is a minimum of 12 LNs. Emerging evidence suggests higher LN yields may improve disease-free survival (DFS); however, an "optimal" number of LNs has yet to be definitively established. The aim of this study was to correlate LN yield with survival outcomes in patients undergoing surgery for nonmetastatic CRC.

METHODS

The Bowel Cancer Outcomes Registry (BCOR) is a clinical quality registry in Australia and New Zealand. Post-operative patients aged ≥ 18 years with histologically confirmed CRC, nonmetastatic disease at diagnosis and with follow-up status documented were included. Post-operative outcomes and survival were assessed with logistic regression. The primary endpoint was CRC-specific mortality. Secondary endpoints were CRC recurrence and all-cause mortality.

RESULTS

Of 91 271 patient episodes, 10 616 individual eligible patients were identified (45.4% male, n = 4828). The median number of LNs resected was 18 [quartiles 0-12, 13-17, 18-23 and > 23]. A significant difference in CRC-specific mortality was seen between quartiles (p = 0.023), with the primary significant difference demonstrated between the lowest quartile (≤ 12 LNs) and other groups. On long-term follow-up, CRC recurrence and CRC-specific mortality were higher in the group with ≤ 12 LNs resected (16.0% vs. 14.0%, adjusted p = 0.049 and 4.5% vs. 3.3%, adjusted p = 0.037 respectively).

CONCLUSION

This study supports the current consensus that > 12 LNs are required for adequate staging and oncological clearance in CRC surgery, and demonstrates yields ≤ 12 LNs are associated with higher CRC recurrence and mortality.