Pathological examination of 12 regional lymph nodes and long-term survival in stages I-III colon cancer patients: an analysis of 2,056 consecutive patients in two branches of same institution.

Purpose: Pathologic examination of at least 12 lymph nodes (LNs) is widely accepted as a standard for colon cancer surgery. We sought to address its association with patient source, other clinicopathological factors, and survival by comparing information from two branches in a large single institution.

Methods: Patients with stages I-III adenocarcinoma of the colon between 1998 and 2003 were identified from the Chang Gung Colorectal Tumor Registry in two branches (Linkou and Kaohsiung branches) of same institution. We used multivariate analysis to adjust for variables with P < 0.1 in univariate analyses.

Results: A minimum of 12 examined nodes were observed in 80% of patients in Linkou branch versus 25% in Kaohsiung branch (P < 0.0001). Younger age, right hemicolectomy, larger tumor, higher tumor stage, higher caseload of surgeons, and patients at Linkou branch with an odds ratio (OR) as high as 23 (95% CI, 17-31) were independently associated with a higher frequency of ≥12 examined nodes. Patients with examined node number of <12 had a greater risk of recurrence within stages II and III (stage II: adjusted OR 1.88, 95% CI 1.27-2.79; stage III: adjusted OR 1.58, 95% CI 1.15-2.17) but not within stage I (OR 0.73, 95% CI 0.23-2.24).

Conclusions: The results confirm that factors influencing nodal harvest are multifactorial and the examined LN number of 12 or more is associated with an increased long-term survival in stages II-III colon cancer. It is possible to adequately sample and examine a sufficient number of nodes in the majority of colon cancer specimens by standardized conventional methods.