[Reduced operation for rectal cancer]

The effectiveness of extended dissection of higher-ranked lymph nodes in patients with rectal cancer has been well recognized recently. However, to prevent postoperative bladder and sexual dysfunction, reduced lymphadenectomy and autonomic nerve preservation are necessary. By definition a reduced operation for rectal cancer attempts to preserve the autonomic nerve and the levator ani muscles without hampering recovery. To clarify the indication of reduced operation for rectal cancer, 219 patients with rectal cancer who underwent resections at our hospital between 1980 and 1986 were analyzed. The relationship of the depth of tumor invasion through the bowel wall to lymph node metastasis in rectal cancer was examined. In cases of rectal cancer limited to submucosa or muscularis propria, the degree of metastatic spread was n0 or n1 (+). In the cases of rectal cancer invading subserosa, serosa or contiguous structures, the degree of metastatic spread was n3(+) or n4(+). Concerning the relationship of the histopathological type and 5-year survival rate, the corrected 5-year survival rate was 72.46% in cases of well and moderately differentiated adenocarcinoma, and 48.84% in cases of poorly differentiated adenocarcinoma and undifferentiated carcinoma. From these results, reduced lymph node dissection and autonomic nerve preservation are possible in patients with well and moderately differentiated adenocarcinoma with invasion into the mucosa, submucosa and muscularis propria.