A Proposal for Novel Standards of Histopathology Reporting for D3 Lymphadenectomy in Right Colon Cancer: The Mesocolic Sail and Superior Right Colic Vein Landmarks: The Mesocolic Sail and Superior Right Colic Vein Landmarks

Background: Strong agreement exists concerning the standards of pathologic reporting for total mesorectal excision and complete mesocolic excision. It represents a quality standard that correlates with survival. However, no agreed standards of reporting are available to define D3 lymphadenectomy for right colectomy. Objective: The purpose of this study was to define anatomopathological standards of specimen quality obtained from the surgical specimen when an oncologic right hemicolectomy with D3 lymphadenectomy has been correctly performed. Design: This study was conducted in 2 different phases. The first part consisted of a cadaver-based study of right colon anatomy, and the second part consisted of a prospective assessment of a series of surgical specimens obtained after right hemicolectomy for cancer. Settings: The anatomic phase of the study was performed in collaboration with the University of Valencia Department of Anatomy and Embryology. The second part was performed at a colorectal unit of a tertiary hospital. Patients: Seventeen cadavers were used for the first phase, and 65 surgical specimens were examined for the second part of the study. Main Outcome Measures: In each specimen, the pathologists looked for anatomic structures defined as markers of quality standards of the D3 lymphadenectomy during the first phase. Specimens were classified as complete, partial, and incomplete D3 lymphadenectomy. Results: Twenty percent of specimens were classified as incomplete D3 lymphadenectomy, 31% as partial, and 49% as complete. A median number of 14 (6-64), 22 (11-47), and 29 (14-55) lymph nodes were isolated (p = 0.01). Similarly, the median numbers of lymph nodes isolated in the area of D3 lymphadenectomy were 0 in incomplete, 1 (0-5) in Partial, and 3 (0-8) in Complete D3 lymphadenectomy specimens (p = 0.0001). Limitations: A large multicenter study with adequate power is needed. Conclusions: We propose the right mesocolic sail and trunk of superior right colic vein as new and reproducible anatomopathologic standards of D3 lymphadenectomy in oncologic right hemicolectomy.