Fecal continence following partial resection of the anal canal in distal rectal cancer: Long-term results after coloanal anastomoses

Background. The aim of the study was to assess the influence of partial exc ision of the superior portion of the anal canal (AC) when necessary for tum or margin clearance in distal rectal cancer on fecal continence after coloa nal anastomoses. Methods. Between 1977 to 1993, 209 patients with middle and lower third rec tal cancers underwent complete rectal excision and coloanal anastomoses. Fo r very low tumors, located at or below 5 cm from the anal verge (AV), varyi ng portions of the superior segment of the AC were excised for tumor margin clearance. The magnitude of resections was inversely proportional to the h eight of the anastomosis from the AV. The patients were categorized into 3 groups according to their level of anastomoses from AV: group 1, patients w ith anastomoses from 0.5 to less than 2 cm from AV (1 to 2.5 cm of AC resec ted, ie, major resection); group 3 anastomoses at 2 to less than 3 cm from AV(less than 1 cm of AC resected, ie, minor resection); group 3, with anast omoses at 3 to 3.5 cm from AV (AC completely preserved). A standard questio nnaire, physical examination, and anal manometry at intervals of 3, 6, 12, 24, 36, and 48 months were performed prospectively to assess anal continenc e. Results. The patients in the 3 categories were matched for age, gender stag e, presence or absence of a colonic J-pouch, preoperative neoadjuvant radio therapy and surgical technique. Fourteen patients with postoperative radiot herapy were excluded from the clinical assessment. Mean follow-up was 33.5 months. There were 43 patients in group 1, 75 in group 2, and 73 in group 3 for clinical assessment. In the first year; there was Progressive improvem ent in anal continence in all 3 groups. At 2 years, 50% in group, 1, 73% in group 2 and 62% in group 3 were fully continent. The proportion of patient s fully continent in group I remained unchanged as compared to continued im provement for groups 2 and 3 following the first year. At 4 years, 50% in g roup 1, 80% in group 2, and 68% in group 3 were completely continent. The d ifference among the 3 groups was not statistically significant. Conclusions, For distal rectal cancer; where tumor margin clearance necessi tates partial resection of the superior portion of the AC, when limited to less than 1 on, the proportion of patients remaining fully continent is sim ilar to those with complete AC preservation. More substantial excisions of the AC can still result in satisfactory anal continence, such that followin g the fourth year one half of the patients can expect to be fully continent .