Lymph node counts as an indicator of quality at the hospital level in colorectal surgery.

BACKGROUND

Substantial evidence suggests that the number of lymph nodes examined in colorectal cancer (CRC) is a powerful predictor of outcomes. However, the lymph node count as a benchmark of quality in CRC is controversial. We sought to examine the impact of lymph node counts on disease-specific survival (DSS) of CRC patients at the hospital level.

STUDY DESIGN

This study used data obtained between 1994 and 2003 from Region 5 of the California Cancer Registry. Hospitals in Region 5 of the California Cancer Registry were stratified according to the median number of nodes examined and grouped according to the median number of nodes examined, <7, 7 to 9, and ≥10. These hospital groups were then evaluated for the frequency of meeting the 12-node threshold, frequency of positive lymph nodes, and DSS at the hospital level.

RESULTS

Median number of nodes examined in group A was 4 (mean 5.6, SD 5.9), in group B was 8 (mean 9.7, SD 8.5), and in group C was 10 (mean 11.3, SD 9.2). In group A, 13.7%, in group B 32.8%, and in group C, 42.8% met the 12-node threshold. The frequency of N1 and N2 disease for group A was 20.7% and 9.1%, 19. 7% and 11.1% for group B, and 20.1% and 11.3% for group C (p = 0.12). Five-year DSS was 72.7% for group A, 73.7% for group B, and 76.7% for group C (p = 0.002). DSS survival of N0 patients for group A was 78.6%, 81.5% for group B, and 85.1% for group C (p < 0.0001). There was no statistically significant difference in DSS for N1 (p = 0.18) or N2 (p = 0.90) between the 3 groups.

CONCLUSIONS

Lymph node counts can have value as a benchmark of surgical/pathologic quality in node-negative CRC. These results question the value of lymph node counts as a benchmark of surgical/pathologic quality for node-positive CRC.