Indication for Bowel Resection Following Endoscopic Polypectomy or Local Excision for Invasive Polyps of the Lower Rectum

Toshio Yagyu, Nobuteru Kikkawa, Hideyuki Mishima, Isamu Nishisyou, Eisei Shin, Yasutoku Hasuike, Kenji Kobayashi, Tetsurou Kobayashi

Department of Surgery, Osaka National Hospital

Between 1977 and,1995, 303 patients with colorectal polyps containing adenocarcinoma invading as far as the submucosa (colon 177, upper rectum 55, lower rectum 71) were treated. Sixteen of 232 patients with invasive polyps of the colon and upper rectum and 6 of 71 patients with invasive polyps of the lower rectum were found to have metastatic lymph nodes. Histologically, all specimens were examined to evaluate the risk for metastasis. The findings revealed that lymphovascular channel invasion (p<0.01), histologic type of the invasive front (p<0.05) and level of invasion correlated with the risk of metastasis. Further analysis in the lower rectal group showed that among these patients, the incidences of lymph node metastasis via lymphovascular channel invasion, histologic type of the invasive front and level of invasion were nearly equal to the respective incidences in the colon and upper rectal groups. Our findings suggest that these three risk factors are also useful in the lower rectal group of patients, for determining the indications for bowel resection following endoscopic polypectomy or local excision. Recently, as coloanal anastomosis after rectal resection has become well established, sphincter-preserving operation has been applied for a large majority of bowel resection for invasive polyps of the lower rectum.

Key words
lower rectal cancer invading the submucosa, lymph node metastasis, polypectomy followed by bowel resection

Reprint requests
Toshio Yagyu Department of Surgery, Osaka National Hospital
2-1-14 Houenzaka, Tyuuouku, Osaka City, 540 JAPAN

Accepted
December 11, 1996

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