[Computer-assisted 3D-navigated laparoscopic resection of a vanished colorectal liver metastasis after chemotherapy]

Modern chemotherapy regimen for colorectal cancer results in complete radiologic remission in a substantial number of cases. However, these "vanished liver metastases" (VLM) often contain vital tumor cells, which mandates the resection of such lesions. In these cases, intraoperative identification of VLM can be challenging, in particular in laparoscopic approaches. We describe the first laparoscopic computer-assisted 3D-navigated resection of a VLM.

A 60-year-old patient with a synchronous liver metastasis (segment IVb) of sigmoid colon cancer (T4 N1 M1) was referred to our center for elective liver resection after laparoscopic sigmoid resection and systemic chemotherapy (FOLFIRI/Panitumumab). The metastasis was not visible anymore on preoperative CT or sonography. Thus, a 3 D reconstruction of the liver was performed. The size of the initial metastasis (before chemotherapy) was transferred into the current CT. A computer-assisted 3D-navigated laparoscopic resection of the metastasis was performed on these fused images. The metastasis was also not clearly visible upon intraoperative ultrasound. Histology of the resected specimen revealed a 0.5 cm metastasis with predominantly vital tumor cells (regression degree 4 of Rubbia-Brandt) and a sufficient resection margin of at least 7 mm. The postoperative course was uneventful.

Computer-assisted 3D-navigation enabled a safe oncologic resection of a vanished liver metastasis after chemotherapy. This technique was particularly helpful due to the limited haptic feedback of laparoscopic surgery. Further studies are necessary to verify the clinical benefit of computer assisted 3D-navigated liver surgery.