Current Aspects of Sphincter Preservation in the Surgical Therapy of Rectal Cancer

Abstract

Treatment of rectal cancer has changed fundamentally over the past 10 years. In the 1970s and 1980s the majority of patients with carcinoma of the rectum were still treated by operative abdominoperineal excision, as proposed by Miles in 1908. For the patients, this resulted in a definitive loss of continence and the formation of an end colostomy located in the left iliac fossa. The rationale of this radical and mutilating approach was that only by such a procedure could tumor relapse be safely avoided. Apart from these deficits in knowledge on tumor biology, the limited and hitherto insufficiently developed operative techniques further restricted the possibilities of restitution of intestinal continuity in the small pelvis or in the supraanal region. With the rediscovery of pathoanatomical and pathophysiological knowledge comprehensively presented by Westhues as early as in the 1930s, a reorientation process set in which led to new surgical concepts for the therapy of rectal cancer (Westhues 1934). The key fact supporting this is that intramural tumor dissemination beyond 2 cm towards the distal end of the rectum is extremely uncommon The lymphatic drainage of the rectum, beginning at the levator level, primarily follows a central direction. Therefore, to avoid local recurrence, safety margins are less determinative distally than laterally (Stelzner 1995; Mac Farlane et al. 1993; Hermanek and Gall 1981). At the same time operative techniques have been developed allowing for a safe anastomosis deep in the small pelvis (Eigler 1991; Gall 1991; Schumpelick and Braun 1991). According to tumor biology the probability of lymphatic metastasis depends on the size and even more so on the depth of invasion and the degree of differentiation of the tumor (Brodsky et al. 1992; Cohen 1993), making it feasible to treat selected tumors in the distal third of the rectum exclusively by local excision. These developments have had the consequence that sphincter-saving treatment is possible in more than 70% of all rectal carcinoma patients without increased risk of recurrence. The relevant treatment strategies along with their indications and their results are presented and analyzed in the following.