[Clinic study of lateral lymph node metastasis in advanced lower rectal cancer]

To evaluate the risk factors of lateral lymph node metastasis in advanced lower rectal cancer and its correlation with local recurrence and prognosis.

Data from 96 consecutive patients with advanced lower rectal cancer underwent curative surgery with lateral dissection were retrospectively analyzed. The correlations of lateral lymph node metastasis with clinicopathologic characteristics, local recurrence and prognosis were investigated.

Lateral lymph node metastasis was observed in 14.6 (14/96) of the cases. In 40 patients with tumor diameter > or = 5 cm, 10 (25.0%) patients were found with lateral lymph node metastasis; while in the other 56 patients, only 4 (7.1%) cases were found with lateral lymph node metastasis (P < 0.05). Lateral lymph node metastasis was more frequent in patients whose tumor infiltrated full range of the intestinal wall (70%) than patients with 3/4, 2/4 and 1/4 intestinal wall was infiltrated (12.0%, 6.7% and 6.3%, respectively) (P < 0.05). Lateral lymph node metastasis rate of poorly differentiated carcinomas was significantly higher than those of moderate and well-differentiated ones (30% vs. 9.1% and 4.5%, P < 0.05). Local recurrence occurred in 18.8% (18 of 96 cases) of patients. Local recurrence in patients with positive lateral lymph node metastasis was 64.3%, while 11.0% in those without lateral lymph node metastasis (P < 0.05). Kaplan-Meier survival analysis showed significant improvements in median survival for patients with negative lateral lymph node metastasis over patients with lateral lymph node metastasis (80.9 +/- 2.1 vs. 38 +/- 6.7 months, log-rank P < 0.05).

Tumor diameter, degree of tumor infiltration and histological differentiation are significant risk factors of lateral lymph node metastasis in advanced lower rectal cancer. Lateral lymph node metastasis is an important predictor of local recurrence and prognosis of patients.