| Theme |
Recent advances in the diagnostic imaging and the treatment of liver metastates from colorectal cancer |
| Title |
Hepatic resection for colorectal liver metastases (non-anatomical hepatectomy) |
| Author |
Junji Yamamoto |
Gastrointestinal Surgery, Cancer Institute Hospital |
| Author |
Yoshihiro Sakamoto |
Gastrointestinal Surgery, Cancer Institute Hospital |
| Author |
Makoto Seki |
Gastrointestinal Surgery, Cancer Institute Hospital |
| Author |
Toshiharu Yamaguchi |
Gastrointestinal Surgery, Cancer Institute Hospital |
| Author |
Tetsuichiro Muto |
Gastrointestinal Surgery, Cancer Institute Hospital |
| [ Summary ] |
Surgical resection is the only way to achieve a complete cure for colorectal liver metastases. The resection rate for metastatic colorectal carcinoma varies from 22% to 52%. Such rates depend on various factors, including tumor-related variables and technical aspects. Our policy is that hepatectomy should be applied in as many cases as possible if complete removal of tumorous deposits is possible. In accordance with this policy, we recommend that hepatectomies should be adaptable to various tumorous conditions, not limited to anatomical resection or by the distance of the surgical margin. Although metastatic lesions show an affinity for intrahepatic vessels in the portal tract, they rarely extend in the liver via such structures as do hepatocellular carcinoma. Two to thirds of the patients with two to four metastatic tumors display bilobarly distributed deposits in the liver and around 80% of those with five or more tumors have bilobar disease. This fact indicates that multiple tumors are more likely to derive from multiple metastatic origins than from re-metastasis of single tumors. A narrow surgical margin reportedly has an adverse effect on the patient's outcome after surgery, especially when it is involved with the tumor. Many surgeons have advocated that a hepatectomy with a sufficient margin of more than 1 cm is necessary for the surgical therapy of colorectal liver metastases. However, this 1cm-or-more margin policy for curative resection may limit the applications for the surgical therapy for liver metastases. Multiple resections of bilateral tumors are required to preserve non-cancerous liver tissue by securing the portal tracts, thus producing liver transection planes close to the tumor margin. In addition, microscopic satellite deposits were rarely found in the parenchyma within 1cm from gross metastatic tumors either in our previous study or the study using genetic markers. Thus, securing a margin of more than 1cm for metastatic colorectal cancer cannot be justified on an oncological basis. Hepatectomy can be applied for a larger proportion of patients with colorectal liver metastases without jeopardizing the post-resection outcome in combination with minor resection. Anatomical he patectomy is not necessary, if there are no difficult technical problems. Positive surgical margins implicating microscopic residual cancer cells, thus should be avoided. However, a generous surgical margin is not a necessary condition for curative hepatic resection. |