Objective: To investigate the resection range of mesorectum and rectum below the inferior margin of tumor for the total mesorectum excision (TME) in middle-low rectal cancer.
Methods: Sixty patients were enrolled in the study. After TME operation, serial 5 mm interval sections were made in specimens of middle-low rectal cancer. The retrograde metastasis of rectal cancer was observed by routine HE staining.
Results: The phenomena of retrograde metastasis in mesorectum were found in 15 cases, and the distance of retrograde metastasis was 0.5-4.0(2.47+/-1.06) cm, which was correlated with Dukes stage, lymph node metastasis and histological differentiation. The retrograde metastases in bowel were found in 11 cases, and the distance of retrograde metastasis was 0.5-4.0 (1.64+/-1.16) cm, which was correlated with histological differentiation.
Conclusions: The distal mesorectum should be resected at least 4 cm when TME is carried out, and the distal bowel at least 2.5 cm. More than 5 cm mesorectum and bowel should be resected when advanced Dukes stage, extensive lymph node metastasis and poor histological differentiation occurred.