Management of Submucosal Invasive Colorectal Cancer in View of Long-term Follow-up Outcome

Kazuo Hase, Hidetaka Mochizuki*, Katsuyuki Utsunomiya, Tsukasa Yoshizumi*, Kazuyoshi Yoshimura*, Kenji Kuranaga, Hideki Kobayashi, Chiyuki Watanabe, Masaru Ishiyama, Shoetu Tamakuma*

Department of Surgery, Self-Defense Force Central Hospital
*First Department of Surgery, National Defense Medical College

One hundred and two patients underwent curative resection of submucosal invasive colorectal carcinomas in the first period, between 1971 and 1989. All patients were followed for at least 5 years (mean=88.5 months). Lymph node metastasis, found in 13 patients (12.7%) was associated with a worse outcome: 38.5% of node (+) patients developed recurrence, vs 5.6% of node (-) patients (p=0.002). The cumulative death curve from cancer was also worse in node (+) vs node (-) (p<0.001). Five histopathological characteristics were identified as risk factors for lymph node metastasis: 1) small clusters of undifferentiated cancer cells in the invasive front of the lesions; 2) a poorly demarcated invasive front; 3) moderately or poorly differentiated cancer cells in the invasive front; 4) extension of the tumor to the middle or deep submucosal layer; and 5) cancer cells in vessels. Whereas patients with ≤ 3 risk factors had no nodal spread, the rate of lymph node involvement in patients with 4 or 5 risk factors was 33.3% and 61.5%, respectively. In the second period, between 1990 and 1993, 30 patients underwent initial endoscopic polypectomy of submucosal invasive colorectal carcinomas. Eleven patients with 4 or 5 risk factors had open surgery, and lymph node metastasis was found in 4 of them. Nineteen patients with ≤ 3 risk factors were followed without open surgery and no recurrence appeared in the follow-up period of 2l to 68 months (mean=44.9 months). Therefore appropriate bowel resection with lymph node dissection is indicated if such a lesion exhibits 4 or 5 risk factors for metastasis. These findings may be helpful in this era of increasing endoscopic removal of colorectal tumors.

Key words
colorectal cancer with submucosal invasion, risk factors for lymph node metastasis, long-term follow-up outcome

Reprint requests
Kazuo Hase Department of Surgery, Self-Defense Force Central Hospital
1-2-24 Ikejiri, Setagaya-ku, Tokyo, 154 JAPAN

Accepted
December 6, 1995

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