Current strategies for preoperative conditioning of the liver to expand criteria for resectability of hepatic metastases

Colorectal cancer (CRC) is among the most commonly diagnosed cancers, and the liver is its most frequent metastatic site. Colorectal liver metastases (CLM) are synchronous in 15–25 % of the CRC patients and metachronous in 20–25 %. In recent decades, 5-year-overall survival following curative liver resection of CLM has increased to 35–58 %. This improvement owes largely to advances in CLM multimodality treatment.

In recent years, the CLM resectability criteria have also shifted, following several encouraging studies reporting the possibility of R0 resection for all tumors while preserving a sufficient volume of residual liver. In this context, multimodal approaches including portal vein embolization (PVE), associating liver partition with portal vein ligation for staged hepatectomy (ALPPS) and two-stage hepatectomy after neoadjuvant chemotherapy were developed to induce hypertrophy of the future liver remnant (FLR) to fulfill minimal liver volume requirements. Liver function tests and scores could be a helpful tool in patient selection and prediction limit of the hepatic parenchymal reserve.

Generally, at least 20 % of the total liver volume should be preserved in the case of a healthy liver, whereas at least 30–60 % should be preserved for livers impaired by chemotherapy-associated steatosis or hepatitis. Further use of ischemic or pharmacological preconditioning of FLR tissue such as stem cell transplantation could help to prepare the liver for extended resections and to avoid postoperative liver failure.

Because of shifting CLM resectability criteria and encouraging survival rates following curative resection in the context of multimodality treatment, extended liver surgery for CLM is increasing. To condition the liver for extensive surgery and to ensure adequate postoperative liver function, several approaches were developed and routinely practiced in clinical centers.