Manual dissection of adenocarcinoma of the lower third of the rectum specimens for detection of lymph node metastases smaller than 5 mm

BACKGROUND: The question of whether manual dissection when searching for metastatic lymph nodes from rectal cancer (less than 5 mm) is a reliable method remains controversial. METHODS: We examined 50 consecutive cases of primary adenocarcinoma of the rectum treated with a sphincter-sparing total rectum resection, total mesorectum excision, and coloanal anastomosis. We used a manual method for the detection of lymph nodes. RESULTS: One thousand seven hundred ninety-three lymph nodes were found (mean, 36 per patient). One hundred seventy-four contained metastases. Seventy-nine (45.4%) of the affected lymph nodes were less than 5 mm in greatest dimension. The percentage of metastases to small lymph nodes was similar to the percentage reported by Kotanagi (50%), but lower than the report of Herrera (78%), who used a clearing technique to search for regional lymph nodes. CONCLUSIONS: A median 17 months follow-up in these patients demonstrated that metastases in small lymph nodes are important in the accurate staging of rectal tumors and that a manual method of searching for small lymph nodes is reliable.