Effects of a Preoperative Capsaicin-Containing Diet on Postoperative Liver Injury Repair: A Randomized Controlled Trial

Inclusion Criteria:

• Age 18 to 75 years, of any sex.

A focal liver lesion scheduled for elective open or laparoscopic liver resection, such as hepatocellular carcinoma, colorectal liver metastases, or hepatic hemangioma.

Child-Pugh class A or B with a score of 7 or less, and indocyanine green retention at 15 minutes (ICG-R15) of 20% or less.

Planned intraoperative hepatic inflow occlusion.

An anticipated future liver remnant of at least 30% in patients with a normal liver or at least 40% in patients with cirrhosis.

Ability to tolerate an oral chili powder challenge, such as 0.5 g without gastrointestinal discomfort.

Willingness and ability to comply with the standardized study diet initiated 2 days before surgery, with a planned capsaicin dose of 7.5 mg/day in three divided doses with meals for participants assigned to the capsaicin group, and provision of written informed consent.

No severe cardiac, pulmonary, or renal dysfunction, with an estimated glomerular filtration rate (eGFR) of at least 60 mL/min.

No history of liver transplantation or other organ transplantation.

Exclusion Criteria:

• Pregnancy or breastfeeding.

A history of or current malignancy other than the disease for which liver resection is planned, unless cured for at least 5 years without recurrence. Hepatocellular carcinoma scheduled for resection, and colorectal liver metastases together with their corresponding colorectal primary cancer, are not excluded under this criterion.

Persistent preoperative elevation of transaminases or total bilirubin above twice the upper limit of normal that does not improve with treatment, or a white blood cell count below the lower limit of normal.

A requirement for a combined radical oncologic procedure, such as pancreaticoduodenectomy or radical resection for hilar cholangiocarcinoma.

Tumor thrombus in the main portal vein, the right or left portal vein branch, a hepatic vein, or the inferior vena cava.

Severe cirrhosis with a Child-Pugh score of 8 or higher, or moderate to severe esophagogastric varices identified by endoscopy.

Active bleeding, a coagulation disorder with an international normalized ratio (INR) greater than 1.5 or a platelet count below 100 × 10^9/L, or another contraindication to surgery.

Severe cardiac, pulmonary, or renal dysfunction, defined as New York Heart Association (NYHA) functional class III or IV, forced expiratory volume in 1 second (FEV1) below 50% of the predicted value, or eGFR below 60 mL/min.

A history of or current active peptic ulcer disease, severe gastritis, gastroesophageal reflux disease (GERD), or a known allergy to chili powder or capsaicin.

Severe infection, active tuberculosis, autoimmune hepatitis, or another acute or chronic systemic disease.

Participation in another interventional clinical trial or use of an investigational drug affecting liver function within the preceding 3 months.