直腸癌肛門温存手術の適応に関する検討

点击翻译按钮获取中文摘要

1) Vertical Spread to Levator and External Sphincter of Low Rectal CancerBackground : Intersphincteric resection (ISR) enables us to obtain a certain extent of distal margin and preserve sphincter function. But, there were still little data of how low rectal cancers spread into anal canal. In the anal canal, levator and external sphincter are striated muscle, surface of which should be the surgical margin of ISR. Thus far, vertical spread of low rectal cancer to this striated muscle has little been studied.Objectives : The aim of this study is to evaluate vertical spread of low rectal cancer and to determine unfavorable factors that shorten distance between cancer and striated muscle (levator and external sphincter) as to undergo ISR with more appropriate patient selection.Materials and Methods : We conducted the specimen resected by rectal amputation from 53 patients, having T2-3 tumor and the lower edge of the tumor was within 2cm from the dentate line or invading beyond dentate line … More . They were composed of 36 males and 17 females with a mean age of 61.5±10.4 years at operation (range, 32-82 years). No patients received preoperative adjuvant therapy. We assessed both vertical spread and distal spread of the tumor. Vertical spread to striated muscle (levator or external sphincter) was estimated by measuring the shortest distance between the tumor and the striated muscle (T-SM distance). We also assessed how cancer spreads close to striated muscle (levator or external sphincter).Results : Distal spread was observed with 15 specimens. Length of distal spread in the 15 specimens was 4.2±3.0 millimeters (range, 1-10 millimeters). Mean distance between the tumor and the striated muscle (T-SM distance) was 9.1±7.2 millimeters (range, 0-32 millimeters). According to univariate analysis of risk factor shortening T-SM distance, predominant histological type excepting well or moderately differentiated adenocarcinoma, short T-DL distance and distal spread are the factor shortening T-SM distance. According to multivariate analysis, T-DL distance and distal spread is independent factor of short T-SM distance, whether the short distance is 2 millimeters or 5 millimeters. As to invading patterns of cancer to striated muscle, distance between cancer and the striated muscle were shorter in the deep part of external sphincter than the superficial part in most cases.Conclusion : Indication of ISR to advanced low rectal cancers should be limited to that lower edge was oral to dentate line and was not accompanied by distal spread. Anal manipulation during ISR should be performed from abdominal procedure prior to anal procedure. Less