Assessing the quality of colorectal cancer staging: Documenting the process in improving the staging of node-negative colorectal cancer

Hypothesis: Examination of 14 or more nodes is the optimal criterion to accurately stage node-negative colorectal cancer and predict outcome. Design: Case series. Setting: Three university-affiliated community medical centers. Patients: A total of 2149 individuals with apparently localized, invasive colorectal cancer examined between January 1, 1990, and December 31, 2002. Intervention: Study of tumor registry data. Main Outcome Measures: Nodal status and disease-specific survival. Results: 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. Conclusions: 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.