Surgical Therapy for Colorectal Cancer Invading the Muscularis Propria

Naoya Murase, Satoshi Okabe, Hiroshi Kuwabara, Masaru Udagawa, Shunrou Otukasa, Takehiro Arai, Syoji Maruyama, Hironori Yamashita and Takehisa Iwai

1st Department of Surgery, School of Medicine, Tokyo Medical and Dental University

We reviewed 58 patients with colorectal cancer invasion of muscularis propria (mp cancer) for the purpose of determining proper surgical treatment. In this study, we subclassified mp cancer into three grades (mp1∼mp3) according to the degree of vertical invasion, compared mp cancer with cancer invasion of submucosa (sm cancer), and contrasted rectal and colonic mp cancer clinicopathologically. In addition, thorough investigation of patients who died due to cancer and who had node involvement was conducted. The results obtained were as follows: 1) Macroscopically, the frequency of elevated type in mp1 cases was significantly higher in contrast to mp2 or mp3 cases. 2) In comparison with sm cancer, mp cancer showed marked venous invasion. But there was no difference between Grade-III sm cancer (deep invasion) and mp1 cancer. 3) In Comparison with colonic mp cancer, rectal mp cancer showed ulcerated type appearance with clear margin more frequently, higher degree of venous invasion and lower five-year survival rate. 4) Seven patients died due to cancer. All had rectal cancer with invasion of mp2 or mp3 and had larger tumors than other patients. 5) Seven of 34 patients with rectal cancer had lymph node metastasis, and all lesions were located in Ra∼P. Only one patient had lateral lymph node metastasis. We conclude that proper surgery for mp1 could be similar to the operation for sm cancer, and that for mp2 or mp3 we should add D3 lymph node dissection suitable especially in case of Ra∼P.

Key words
colorectal carcinoma invading the muscularis propria, subclassification of mp cancer, lymph node metastasis, lateral lymph node dissection, autonomic nerve preserving operation

Reprint requests
Naoya Murase First Department of Surgery, Tokyo Medical and Dental University 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519 JAPAN

Accepted
September 22, 1999

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