Purpose: To evaluate the prognostic value of lymph node metastasis with extracapsular extension (ECE) for local control and metastasis-free survival in rectal cancer.
Methods and materials: A total of 145 rectal cancer patients were treated with surgery and postoperative radiochemotherapy. Patients were grouped according to nodal status (node negative, n = 49; node positive without ECE, n = 64; node positive with ECE, n = 32). In addition, well-known prognostic factors such as International Union Against Cancer (UICC) stage, T and N stage, presence of lymphangiosis, and grade were assessed. The end points were analyzed by the Kaplan-Meier method, and prognostic factors were compared in a Cox regression model.
Results: Of the entire group, the actuarial 5-year local control and distant metastasis-free survival rate was 85% and 66%, respectively, after a median follow-up of 47 months (range, 14-104). Patients with ECE of lymph node metastasis had an impaired 5-year local control rate (58%) compared with node-negative (83%) and node-positive without extracapsular involvement patients (87%, p = 0.041). Metastasis-free survival also differed for the three groups, with a rate of 40% for those with extracapsular involvement, 54% for those without ECE, and 78% for node-negative patients (p <0.0001). The impact of ECE on local control was confirmed in the regression model (risk ratio [RR] 1.6, 95% confidence interval [CI] 1.01-2.7, p = 0.044). T stage was only of borderline significance (RR 2.4, 95% CI 1.0-5.7, p = 0.052). However, only UICC stage (RR 5.1, 95% CI 2.0-13.1, p <0.001) and the presence of lymphangiosis (RR 2.8, 95% CI 1.4-5.3, p = 0.002) were of independent prognostic value for distant metastasis.
Conclusion: ECE of node metastasis is connected with a substantial decline in local control. The frequency of distant metastasis is increased in this patient group as well, but stage and lymphangiosis are the independent factors for assessment of a patient's risk of systemic spread.