title: [Distal intramural spread of rectal cancer studied on large slices].
abstract: OBJECTIVE
  To study the length of distal intramural spread of rectal cancers, and provide evidence for anal-preserving operations.
  
  
  METHODS
  Specimens of ninety-eight patients with rectal cancers who had been operated from August, 1996 to October, 1997, were collected and their large pathologic slices examined. The length of intramural spread distal to rectal cancers was measured under light microscope. The actual length of spread in live conditions was estimated according to equal proportional shrinkage.
  
  
  RESULTS
  In 48 of the 98 patients, distal intramural spread of the tumor was observed. The length of spread varied from 0.1 cm to 2.5 cm. In 77% of the 48 patients, the length of tumor spread was < 0.5 cm. In only 5 patients was the distance of spread > or = 1.0 cm. Four different ways of tumor invasion were observed: contiguous, lymphatic, neural and venous invasion. Distal intramural spread could be via mucosa, submucosa, inner circular muscular layer, outer longitudinal muscular layer or serosa, either separately or concomitantly.
  
  
  CONCLUSIONS
  Distal intramural spread of rectal cancers can be detected in about 1/2 of the specimens examined on large pathologic slice. In most of them the distance of spread is < 0.5 cm. Occasionally it may be > or = 1 cm. To set the edge of resection > or = 3 cm distal to the rectal cancers is relatively safe in anal-preserving operations.
authors.affiliation: Department of Abdominal Surgery, Tumor Hospital, Sun Yat-sen University of Medical Sciences, Guangzhou 510060, China.
authors.forename: H
authors.initials: H
authors.lastname: Liu
authors.forename: D
authors.initials: D
authors.lastname: Wan
authors.forename: Q
authors.initials: Q
authors.lastname: Wu
mesh_terms: D015179:Colorectal Neoplasms / Q000473:pathology* / Q000601:surgery*; D003107:Colorectal Surgery; D005260:Female; D006801:Humans; D008297:Male; D008853:Microscopy / Q000379:methods; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis