Any efforts to spare patients with T1 carcinomas of the rectum from low anterior resection or even abdominoperineal resection are linked to the risk of locoregional recurrence of about 10% (range, 0-24). This is tolerated in the view of the morbidity and mortality risk related to transabdominal resection, which is as high as 7-68% and 0-6.5%, respectively. Accordingly, in addition to transanal local excision various adjuvant therapy schemes with chemo- and/or radiotherapy were developed, given the uncertainty about the lymph node stage. Another approach was to identify histological risk criteria in the primary tumor in terms of defining the limits of rectum-sparing therapy.
In earlier experimental and clinical studies the investigators researched and applied dorsoposterior extraperitoneal pelviscopy, i.e. perineal access to the soft-tissue areas of the minor pelvis using minimally invasive surgery. in T1 carcinoma of the rectum this technique becomes all the more significant, as the perineal approach makes it possible to perform an endoscopic posterior mesorectal resection (EPMR) in combination with rectum-sparing surgery Thereby the relevant lymphatic field of the lower rectum can be removed and histologically examined. As a consequence EPMR should lower the loco-regional recurrence rate, since the most common causes of such are pre-existent but so far not detectable lymph node metastases besides the incomplete resection of the primary tumor.