by Xavier Muller
Colorectal cancer is the third most common cancer with an estimate of more than 150,000 new cases in 2024 in the United States (1, 2). In approximately one third of patients, colorectal cancer is metastatic at the time of diagnosis, meaning that cancer cells have already spread from the colon or rectum to other organs in the body (2). One of the most frequent metastatic sites of colorectal cancer is the liver (50% of patients). In case the metastases are localized only in the liver, the optimal treatment is to remove them surgically in combination with chemotherapy (3). Of note, resection of liver metastases is only beneficial if all macroscopically visible lesions can be removed. Unfortunately, a complete resection of liver metastases is only possible in up to 35% of patients, owing to anatomical limits imposed upon the surgeon (3).
What are the limits of liver surgery?
In order to understand the limits of surgical resection of liver metastases, one has to focus on liver anatomy. French anatomist Claude Couinaud published the first complete description of the functional anatomy of the liver in 1957 (4). The liver consists of two functional entities, the left and the right hemiliver, which are both supplied by three main structures: a vein, an artery and a bile duct (5). These three structures are referred to as the portal pedicle. There is a right portal pedicle for the right hemiliver and a left portal pedicle for the left hemiliver. The hemiliver can be further divided into individual segments, defined by the bifurcation of the respective portal pedicle into smaller branches (6). One can image the functional liver anatomy as a tree, with the left and right pedicles originating directly from the main trunk before further dividing into smaller branches as we approach the periphery of the tree. In total, there are eight liver segments with a dedicated portal pedicle (6). Read more »