NEXPREM is a single-center non-blinded randomized controlled trial investigating preoperative exercise and nutrition for sarcopenic patients in major hepatic surgery for liver malignancies. Patients with sarcopenia undergoing major hepatectomies have high rates of postoperative complications. Previous studies have demonstrated that preoperative rehabilitation with exercise and nutrition may help reduce the negative impact of sarcopenia. The investigator's hypothesis is that preoperative nutrition and exercise may reduce complications in sarcopenic patients undergoing major hepatectomies. Sarcopenic patients at diagnosis will be randomized in Group A undergoing upfront surgery and Group B undergoing preoperative rehabilitation. Outcome will be overall 90 day morbidity.

Inclusion Criteria:

• Age >18.
• Sarcopenic patients diagnosed by both qualitative and quantitative analysis.
• Patients with primary or secondary liver malignancies.
• Patients undergoing major liver resections intended as 3 or more contiguous segments
• Patients undergoing open, laparoscopic, or robotic resections.

Exclusion Criteria:

• Minor liver resections intended as less than 3 contiguous segments.
• Patients with intrahepatic, hilar, or extrahepatic cholangiocarcinomas.
• Patients with liver tumors for whom 6 weeks interval from diagnosis to surgery could not be waited (i.e., large HCCs on healthy livers not requiring preoperative portal vein occlusion, CRLM without preoperative administration of anti-VEGF drug who therefore do not require 6 weeks of chemotherapy washout)
• Patients with benign liver lesions.
• Patients undergoing extrahepatic liver resections.
• Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy (ALPPS) procedure.
• Patients with physical disabilities, unable to exercise.
• Patients with inadequate kidney function.