[Study on retrograde metastasis rule of middle-low rectal cancer].

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.