Impact of the number of negative nodes on disease-free survival in colorectal cancer patients.

Purpose: Between 1995 and 1999, we observed an increasing number of nodes being recovered from colorectal specimens. Patients with colorectal cancer were studied to determine whether increasing the number of negative nodes recovered would better stage the patient and more accurately predict disease-free survival.

Methods: All patients undergoing colorectal resection with curative intent between 1995 and 1999 at a tertiary referral hospital were retrospectively reviewed. Tumor stage, grade, number of nodes recovered, and the association of these factors with disease-free survival was analyzed.

Results: Three hundred forty-five patients with M0 disease undergoing surgical resection of carcinoma of the colon or rectum were studied. There was no statistically significant difference in tumor stage or grade during the study period. A statistically significant increase in the mean number of nodes recovered was observed during the study period. Node-positive patients did substantially worse than node-negative individuals. When compared with a national cancer registry (OncoPool), we observed a significantly greater number of nodes sampled in our study population and a statistically significant improved disease-free survival between our node-negative patients and that of the national cancer registry population.

Conclusion: The extent of the pathologic assessment of the nodal status of colorectal cancer patients as determined by the number of nodes examined affects disease-free survival. The need for quality control for uniform pathologic assessments is critical.