New classification system for radical rectal cancer surgery based on membrane anatomy

BACKGROUND: Total mesorectal excision along the “holy plane” is the only radical surgery for rectal cancer, regardless of tumor size, localization or even tumor stage. However, according to the concept of membrane anatomy, multiple fascial spaces around the rectum could be used as the surgical plane to achieve radical resection. AIM: To propose a new membrane anatomical and staging-oriented classification system for tailoring the radicality during rectal cancer surgery. METHODS: A three-dimensional template of the member anatomy of the pelvis was established, and the existing anatomical nomenclatures were clarified by cadaveric dissection study and laparoscopic surgical observation. Then, we suggested a new and simple classification system for rectal cancer surgery. For simplification, the classification was based only on the lateral extent of resection. RESULTS: The fascia propria of the rectum, urogenital fascia, vesicohypogastric fascia and parietal fascia lie side by side around the rectum and form three spaces (medial, middle and lateral), and blood vessels and nerves are precisely positioned in the fascia or space. Three types of radical surgery for rectal cancer are described, as are a few subtypes that consider nerve preservation. The surgical planes of the proposed radical surgeries (types A, B and C) correspond exactly to the medial, middle, and lateral spaces, respectively. CONCLUSION: Three types of radical surgery can be precisely defined based on membrane anatomy, including nerve-sparing procedures. Our classification system may offer an optimal tool for tailoring rectal cancer surgery.