Development of surgical concepts in rectal cancer resection and challenges in minimally invasive surgical proctectomy

Abstract

Since the early 1900s there have been dramatic changes in the management of patients with rectal cancer. Surgical approaches initially performed for palliation, have now been adapted, modernised and undertaken as part of a multimodal approach. This has resulted in significant improvements in long-term oncological survival and patient quality of life. With the introduction of total mesorectal excision (TME) in the 1980's, and its global acceptance by the surgical community, local and distant disease-free survival in patients with rectal malignancy has significantly improved. Since the inception of minimally invasive surgery, laparoscopy has seen dramatic changes both in the evolution of technological advances and application in multiquadrant surgery for colorectal malignancy. Favorable short-term clinical benefits and long-term oncological equivalence from many multicentre randomized controlled trials in laparoscopic colonic cancer resection has led the colorectal surgical community to translate and adapt minimally invasive surgical (MIS) techniques for proctectomy in patients with rectal tumours. MIS proctectomy is technically challenging and is associated with a steep learning curve. Reported challenges in the literature continuously identify a group within three common themes which can be divided into patient/anatomical factors, tumour characteristics and the use of neoadjuvant therapies. Despite a large body of evidence highlighting efficacy of MIS in proctectomy, significant challenges exist in male patients with a narrow pelvis and distal tumors. Such patients are at increased risk of a poor surgical specimen, positive distal and circumferential resection margins (CRMs), and increased local recurrence. Despite advances in laparoscopy and robotic platforms, approaching such lesions from a “top down” approach expose the ongoing limitations to lower pelvic access. This technically challenging issue has led to the colorectal surgical community adopting previously taught MIS techniques to develop a “bottom up” transanal approach to TME, now known as transanal TME (taTME) in order to mitigate this increased margin risk.