Green Tea Extract in Treating Patients With Stage 0, Stage I, or Stage II Chronic Lymphocytic Leukemia

DISEASE CHARACTERISTICS:

* Confirmed diagnosis of chronic lymphocytic leukemia (CLL)

  * Stage 0, I, or II disease
  * Previously untreated disease
  * Splenomegaly, hepatomegaly, or lymphadenopathy are not required for the diagnosis of CLL
  * Absolute lymphocyte count \> 10,000/mm\^3
  * Lymphocytosis must consist of small to moderate size lymphocytes, with ≤ 55% prolymphocytes, atypical lymphocytes, or lymphoblasts morphologically
  * Phenotypically characterized B-CLL defined by all of the following criteria:

    * A population of leukemic cells that co-expresses the B-cell antigen CD23 as well as CD5 in the absence of other T-cell markers (CD3, CD2, etc.)
    * Dim surface immunoglobulin expression
    * Exclusively κ or λ light chains
  * Mantle cell lymphoma must be excluded by demonstrating the absence of the t(11:14) by FISH testing
* Patients who require chemotherapy for treatment of CLL, based on any of the following criteria, are excluded:

  * CLL-related symptoms requiring treatment, including any of the following:

    * Unintentional weight loss ≥ 10% body weight within the previous 6 months
    * Extreme fatigue
    * Fevers \> 100.5°F for 2 weeks without evidence of infection
    * Night sweats without evidence of infection
  * Evidence of progressive marrow failure due to CLL involvement of bone marrow as manifested by the development of worsening anemia (hemoglobin \< 11 g/dl) and/or thrombocytopenia (platelet count \< 100,000/mm\^3)

    * Thrombocytopenia due to immune phenomena (ITP) is permitted as long as platelet count is ≥ 100,000/mm\^3and the patient is not on active pharmacologic therapy
  * Massive (i.e. \> 6 cm below left costal margin) or progressive splenomegaly
  * Massive nodes or clusters (i.e., \> 10 cm in longest diameter) or progressive adenopathy
  * Progressive lymphocytosis with an increase of \> 50% over 2 month period, or an anticipated lymphocyte doubling time of \< 6 months

PATIENT CHARACTERISTICS:

* Platelet count ≥ 100,000/µL
* ANC ≥ 1500/µL
* Hemoglobin ≥ 11 g/dL
* Total or direct bilirubin ≤ 1.5 x upper limit of normal (ULN)
* AST (SGOT) and ALT (SGPT) ≤ 2 x ULN
* Creatinine ≤ 1.5 x ULN OR creatinine clearance ≥ 40 mL/min
* May have a history of autoimmune hemolytic anemia (AIHA) and positive Coombs test provided there has not been active hemolysis requiring transfusion or steroid treatment ≤ 10 weeks prior to registration
* ECOG performance status 0, 1, or 2
* Life expectancy of ≥ 6 months
* No uncontrolled infection
* No myocardial infarction within the past 6 weeks
* No New York Heart Association class III or IV congestive heart failure
* Not pregnant or nursing
* Negative pregnancy test
* Must employ adequate contraception (condoms, diaphragm, birth control pills, injections, intrauterine device \[IUD\], or abstinence, etc.) prior to study entry and for the duration of study participation
* No other severe medical or psychiatric illness
* No active hemolysis requiring transfusion or other pharmacologic therapy

PRIOR CONCURRENT THERAPY:

* At least 8 weeks since prior and no other concurrent over the counter green tea or green tea extract
* No prior daily use of over the counter green tea products for medicinal purposes for \> 4 weeks (phase II only)
* No other concurrent chemotherapy, immunotherapy, radiotherapy, or any ancillary therapy considered investigational (utilized for a non-FDA-approved indication and in the context of a research investigation)
* No concurrent combination anti-retroviral therapy for HIV positive patients
* No concurrent oral steroid preparations