Methods to Increase Future Liver Remnant Volume in Patients with Primarily Unresectable Colorectal Liver Metastases: Current State and Future Perspectives.

Radical liver resection of colorectal liver metastases (CLMs) is the only potentially curative treatment. But primary resectability of CLMs ranges from 15% to 20%. Insufficient future liver remnant volume (FLRV) is the main cause of primary unresectability of CLMs. Currently, there are several methods that can optimize FLRV and permit radical resection of CLMs. The basic methods include two-stage liver resection, portal vein embolization (PVE) and portal vein ligation. These methods have very low morbidity and mortality rate. Their disadvantage is the relatively long interval for increase of FLRV, with danger of tumour growth, and also the significant number of patients in whom optimal FLRV increase does not occur. For this reason, two other methods were developed - associating liver partition with portal vein ligation for staged hepatectomy (ALPPS) and PVE with application of hematopoietic stem cells (HSCs). The advantage of ALPPS is the very rapid increase of FLRV, but the method is burdened by higher morbidity and mortality. PVE with HSC application is not associated with complications, it has a faster increase of FLRV compared to PVE and two-staged liver resection, but the role of autologous HSCs in carcinogenesis is not yet clear. All the methods offer secondary resectability for patients with primarily inoperable CLMs, with long-term survival comparable to primary CLM resections. The optimal choice of specific method must be made on a strictly individual basis for the given patient, and depends on the decision of the multidisciplinary team.