Lymph node involvement and tumor depth in rectal cancers: an analysis of 805 patients

BACKGROUND: Superficial rectal tumors are said to involve regional lymph nodes rarely. This presumption must be proven beyond any doubt if less radical surgery is to be offered for such patients. PATIENTS AND METHODS: Eight hundred five cases (467 males; median age, 64 (range, 19-97) years) of rectal cancer were reviewed. RESULTS: Lymph node positivity, number of lymph nodes involved, lymphatic vessel, and venous and perineural invasion were significantly increased with increasing depth of invasion of tumor through the bowel wall in univariate analysis. The percentage of lymph node involvement at each tumor depth was as follows: T1, 5.7 percent; T2, 19.6 percent; T3, 65.7 percent; T4, 78.8 percent. Overall lymph node involvement was 59 percent. For patients younger than 45 years of age, the percentage of lymph node involvement was 33.3, 30, 69.3, and 83.3 percent compared with 3.1, 8.4, 64.2, and 78.8 percent for patients aged 45 years or above for T1, T2, T3, and T4, respectively. CONCLUSION: Increased depths of tumor penetration beyond T1 and age less than 45 years have an excessive incidence of lymph node positivity. The finding of lymphatic vessel invasion on biopsy is highly indicative of lymph node metastasis.