The Role of and Indications for Local Treatment of Rectal Tumors -Based on a Study of Lymph Node Metastasis of Submucosal Invasive Cancers and Diagnosis of the Depth of Submucosal Invasion-

Haruhiko Okamoto, Yasuo Sakai, Takeyasu Suda, Katsuyoshi Hatakeyama

First Department of Surgery, Niigata University School of Medicine

Local treatments such as endoscopic resection, transanal local resection and TEM (Transanal Endoscopic Microsurgery) are useful methods of diagnosing and treating rectal lesions, especially adenomas and early cancers. We investigated the incidence of lymph node metastasis of colorectal submucosal invasive cancer (sm cancer). Among 168 surgical cases of sm cancer, 15 (8.9%) had lymph node metastasis. No lymph node metastasis was detected n those with pedunculated cancers smaller than 15 mm or in those with sessile cancers in which the depth of invasion was sm1a. These lesions, mucosal cancers and adenomas, appear to be curatively treated by local resection. Accuracy in diagnosing the depth of submucosal invasion between preoperative endoscopic diagnosis and pathological diagnosis (sm1 versus sm2 and sm3) was 78.9% for pedunculated tumors and 88.5% for sessile tumors. We have never diagnosed smla cancer as sm2 or sm3 cancer. The treatment ratios for sm cancers in the rectum and colon were as follows. Bowel resection: 23.5%, 46.8%, local treatment followed by bowel resection: 35.3%, 23.5%. The role of local resection is important as curative treatment for tumors with a clinical diagnosis which is neither sm2 nor sm3 cancer. Furthermore it is more important in the rectum than in the colon in trems of diagnostic treatment as well as minimally invasive or palliative therapy for the tumors carrying the possibility of lymph node metastasis.

Key words
submucosal invasive cancer, transanal endoscopic microsurgery, local resection

Reprint requests
Haruhiko Okamoto Department of Surgery, Niigata University School of Medicine
1-757 Asahimachi-dori, Niigata City, 951 JAPAN

Accepted
December 11, 1996

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