The goal of this observational study is to evaluate clinical and oncologic outcomes in adult patients undergoing liver and/or biliary resection for benign and malignant diseases.

This study evaluates postoperative morbidity and mortality within 90 days after surgery, as well as overall survival and disease-free survival in patients with malignant disease.

Participants will:

• undergo standard surgical and perioperative management according to routine clinical practice
• have clinical, surgical, and follow-up data collected from institutional medical records
• be followed for postoperative outcomes and long-term oncologic outcomes up to 5 years

Hepatobiliary surgery is associated with significant postoperative morbidity and mortality, particularly in patients undergoing liver and/or biliary resection for benign and malignant diseases. Despite advances in surgical techniques, perioperative care, and patient selection, outcomes remain variable and influenced by multiple clinical and technical factors.

This is a monocentric ambispective observational cohort study conducted at a high-volume hepatobiliary center. The study includes a retrospective cohort of patients treated between January 1, 2015 and December 31, 2025, and a prospective cohort of patients treated between January 1, 2026 and December 31, 2031. Clinical and oncologic follow-up will continue until December 31, 2036.

The study aims to evaluate short-term and long-term outcomes after liver and/or biliary resection. Primary outcomes include postoperative morbidity and mortality within 90 days after surgery, as well as overall survival and disease-free survival in patients with malignant disease.

Secondary objectives include the identification of predictors of postoperative complications, evaluation of recurrence patterns, comparison of outcomes according to surgical approach and extent of resection, and assessment of the impact of preoperative risk factors and temporal trends.

Data will be collected from electronic medical records, operative reports, radiological and pathological data, and institutional databases. Adult patients undergoing liver and/or biliary resection for benign or malignant diseases will be included according to predefined eligibility criteria.

No study-specific interventions are assigned. All patients will receive standard clinical care according to routine practice. Follow-up data will be collected at predefined intervals, including early postoperative outcomes and long-term oncologic outcomes up to 5 years after surgery.

Inclusion Criteria:

• Age ≥ 18 years
• Patients undergoing liver resection and/or biliary resection at San Jacopo Hospital, Pistoia
• Diagnosis of benign or malignant hepatobiliary disease
• Availability of clinical, surgical, and follow-up data
• For the prospective cohort, provision of written informed consent when required according to local regulations

Exclusion Criteria:

• Age < 18 years
• Pregnancy
• No liver or biliary resection performed
• Biopsy only without resection
• Refusal or unavailability of consent for the prospective cohort when consent is required

Adult patients undergoing liver and/or biliary resection for benign or malignant hepatobiliary diseases at San Jacopo Hospital, Pistoia, a high-volume hepatobiliary center. The study includes both a retrospective cohort (2015-2025) and a prospective cohort (2026-2031).

Individual participant data will not be publicly shared due to privacy and regulatory restrictions. De-identified data may be made available upon reasonable request to the corresponding investigator, subject to institutional approval.