A single-center prospective study to elucidate whether extended robot-assisted right colectomy (e-RARC) performs as well as extended open right colectomy (e-ORC) in terms of specimen quality, and in addition, whether less postoperative morbidity and shorter length of stay (LOS) can be attained. Patients with colonic cancer near the right flexure or the oral part of the transverse colon will be compared excluding the most technically demanding and frail patients in both groups. A total of 40 patients undergoing e-RARC in a prospective series will be included and compared with 44 consecutive patients previously treated with e-ORC.

Complete mesocolic excision with central vascular ligation (CME) is an improvement of surgical technique in the operation for colonic cancer suggested to increase long-term survival. The concept was originally developed for open surgery by W. Hohenberger in Erlangen with excellent survival rates. However, if the tumor is located in the transverse colon or near the right colonic flexure, the procedure is particularly technically demanding, and for that reason most surgeons still prefer to do it by open operation (laparotomy) instead of the minimally invasive approach (laparoscopy) presently recommended for colonic cancer surgery. The advent of robotic surgery has improved the dexterity of instruments used in laparoscopic surgery and pushed the limits of what is possible with a minimally invasive approach. Since minimally invasive surgery is associated with better outcomes in terms of postoperative morbidity, pain, length of stay etc., it would be highly desirable if CME surgery could be done by robot-assisted laparoscopic operation instead of the current open approach. The current single-center study is proposed to elucidate whether extended robot-assisted right colectomy (e-RARC) performs as well as extended open right colectomy (e-ORC) in terms of specimen quality, and in addition, whether less postoperative morbidity and shorter length of stay (LOS) can be attained. Patients with colonic cancer near the right flexure or the oral part of the transverse colon will be compared excluding the most technically demanding and frail patients in both groups. A total of 40 patients undergoing e-RARC in a prospective series will be included and compared with 44 consecutive patients previously treated with e-ORC.

Inclusion Criteria:

• Suspected or verified colonic cancer visualized by colonoscopy and on CT in the anal part of the ascending colon, in the right flexure or in the oral 2/3 of the transverse colon
• Patient is 18 years or older, legally competent and able to comprehend information and give consent
• Tumor is UICC stage I-III on preop CT
• Operation is elective

Exclusion Criteria:

• Previous major open intraabdominal surgery
• Ileus or other acute abdominal condition
• CT scan with suspicion of T4 tumor
• RITA score > 3 (Preop risk and frailty score)
• BMI > 35 kg/m2
• Project surgeon not available