(1) Laparoscopic oncologic left hemicolectomy (2) D3 resection of an advanced hepatic flexure cancer: a presentation of its technical aspects in laparoscopic extended right hemicolectomy (3) Single-fire transaction decreases anastomotic leakage in laparoscopic low anterior resection (4) Robotic en-bloc intersphincteric resection with prostatectomy following chemoradiation: a case report of rectal cnacer invading to the prostate