SIT is a rare congenital anomaly in which the thoracic and abdominal cavity structures are completely opposite to normal. SIT has a reported incidence of 1 in 5000–10000 and patients may have a high risk of cancer [1, 3].

Surgery in patients with SIT is considered more difficult because of the mirror-image anatomy. To perform surgery safely, careful assessment of the anatomy using preoperative imaging is important. 3D-CT and CT angiography are useful for clarifying the anatomy [3].

Colectomy in patients with SIT is a simple change from the usual procedure and reduces the risk of misleading and damaging lesions.

Some reports on laparoscopic procedures in patients with SIT have described the surgeons’ positions, port placement, and use of devices with the nondominant hand [4,5,6]. Most reports suggest changing the positions of the surgeon and assistant, as well as using the same port placement. Oms and Badia [6] suggested a potential advantage for left-handed surgeons in laparoscopic surgery of patients with SIT. Right-handed surgeons encounter technical difficulties when using an energy device with their left hand during laparoscopic surgery. However, these limitations can be overcome by robot-assisted surgery (RS). In RS, multi-joint forceps allow surgeons to operate flexibly and use scissors or energy devices with their dominant hands. These advantages of RS lead to improved surgical safety and enable complicated and precise surgery for any anatomical anomaly.

There have been only four reports to date of RS for colorectal cancer in patients with SIT, and all these reports described rectal cancer (Table 1) [7,8,9,10]. This is the first report of RS for colon cancer.

All these studies used a da Vinci® surgical system (Xi or S). The port positions and procedures were different in each report. One report set the port positions on a horizontal line and used a retraction arm with the left hand. Other reports set port position squares and used a retraction arm with the right hand. No complications occurred in any of the patients. In the present case, the trocar positions were changed to mirror the usual locations during right hemi-colectomy. The da Vinci® Xi system was rolled in from the left side of the patient and performed with single docking. The camera was positioned as usual. The retraction arm was used with the left hand. In our procedure, anatomical understanding was straightforward because the surgical view only required a mirror image to the horizontal, and the surgeons could use forceps with coaxial camera vision. The role of the retraction arm is to retract the surgical field roughly, and there were no difficulties in controlling the retraction arm with the left hand. As a result, the creative procedure was safe.

In conclusion, we safely and efficiently performed robotic colectomy for ascending colon cancer in a patient with SIT. Our RS procedure will help surgeons perform robotic colectomy in patients with SIT.