Examination of 14 or more nodes is the optimal criterion to accurately stage node-negative colorectal cancer and predict outcome.
Three university-affiliated community medical centers.
A total of 2149 individuals with apparently localized, invasive colorectal cancer examined between January 1, 1990, and December 31, 2002.
Study of tumor registry data.
Main Outcome Measures
Nodal status and disease-specific survival.
The number of nodes examined ranged from 0 to 97 (mean ± SD, 18 ± 15 nodes). The mean number of nodes examined in node-positive individuals was 21.0 vs 16.6 in node-negative individuals (P<.001). The mean number of nodes examined at medical center A was 22.3; center B, 17.9; and center C, 14.0. The mean number of nodes examined for T3 and T4 tumors at center A was 26; center B, 20; and center C, 16 (P<.001). The node-positive rate for all T3 and T4 lesions was 49.7% at center A, 57.8% at center B, and 50.0% at center C (P<.001). Despite significant differences in the mean number of nodes examined between medical centers, the overall survival in patients with node-negative colorectal cancer in the 3 medical centers was not statistically different (P = .79). The criterion of examining 14 or more nodes distinguished between individuals at low risk for recurrence and those at increased risk.
Variability exists between medical centers in the pathological analysis of colorectal cancer specimens. However, within an institution, examining a mean of 14 or more nodes accurately stages apparently node-negative colorectal cancer and accurately predicts outcome.