Defined Green Tea Catechin Extract in Preventing Liver Cancer in Participants With Cirrhosis

Inclusion Criteria: * Participants with a clinical diagnosis of cirrhosis based on the investigators evaluation, confirmed by ANY ONE of the three following methods to define cirrhosis: * Established cirrhosis on liver biopsy (Meta-analysis of Histological Data in Viral Hepatitis \[METAVIR\] F4); * Ultrasound, CT or MRI findings consistent with cirrhosis; nodular appearing liver with or without evidence of portal hypertension * Transient elastography (FibroScan) with a result \> 12.5 kPa Etiology of cirrhosis will not be considered in determining inclusion in the study * Participant is able and willing to comply with study procedures, and signed and dated informed consent is obtained * Participant agrees to consume no more than 2 cups of green tea per day and refrain from taking supplements or foods labeled as containing green tea * Participant must be aged \>= 18 years. Because no dosing or adverse event (AE) data are currently available on the use of Polyphenon E in participants \< 18 years of age, children are excluded from this study but will be eligible for future pediatric trials, if applicable * Eastern Cooperative Oncology Group (ECOG) performance status =\< 1 (Karnofsky \>= 70%) * Platelets \>= 75,000 / uL * Hemoglobin \>= 8 g/dL * Serum creatinine OR measured or calculated creatinine clearance within normal institutional limits; glomerular filtration rate (GFR) can also be used in place of creatinine or creatinine clearance (CrCl) within normal institutional…