Who can get the beneficial effect from lateral lymph node dissection for Dukes C rectal carcinoma below the peritoneal reflection?

PURPOSE: This study was designed to identify those patients with Dukes C rectal carcinoma below the peritoneal reflection who might benefit from lateral lymph node dissection.
METHODS: The study involved 104 consecutive Dukes C patients who received total mesorectal excision with lateral lymph node dissection for rectal carcinoma below the peritoneal reflection between 1990 and 2002. The patients were retrospectively divided into three groups: patients without lateral spread (Group I: n = 52), patients with nodal involvement between the inferior hypogastric nerve and the internal iliac artery (Group II: n = 16), and patients with nodal involvement in the obturator space (Group III: n = 36). The patients also were divided into two groups according to the number of lateral nodes involved: less than four (n = 42) and at least four (lateral nodes involved: n = 10). Nodal involvement was determined histologically.
RESULTS: The local recurrence and overall five-year survival rates were 5.8 and 66.9 percent in Group I, 18.8 and 59.8 percent in Group II, and 33.3 and 23.6 percent in Group III, respectively. These outcomes did not differ significantly between Groups I and II, but they were significantly worse in Group III than in Groups I and II, with the survival being significantly better in the patients with less than four histologically positive lateral nodes involved (43.2 percent) than in those with at least four positive lateral nodes involved (0 percent).
CONCLUSIONS: Lateral lymph node dissection was effective for Dukes C rectal carcinoma below the peritoneal reflection with positive lateral nodes involved in the space between the autonomic nerve and the internal iliac artery and in patients with less than four positive lateral nodes.