Lenalidomide Maintenance Post-debulking in Advanced CTCL

DISEASE CHARACTERISTICS: * Diagnoses of advanced T-cell cutaneous lymphoma or mycosis fungoides/Sézary syndrome * Stage IIB-IV disease * Achieved complete or partial response after undergoing prior debulking therapy with 1 of the following recommended\* regimens with or without radiotherapy\*\*: * Gemcitabine hydrochloride IV over 30 minutes on days 1, 8, and 15 of a 28-day course at a dose of 1,000 to 1,200 mg/m² for a total of four courses * Pegylated liposomal doxorubicin hydrochloride IV over 1 hour on days 1 and 15 of a 28-day course at a dose of 20 mg/m² for a total of four courses NOTE: \*These recommended regimens can be altered according to local institutional policies. In case of drug intolerance, the study regimen can be switched from one regimen to the other. NOTE: \*\*Local low-dose/energy-ionizing radiation therapy allowed as part of the debulking process to treat lesions that do not respond after 3 courses of debulking chemotherapy. * Sézary cell burden must be decreased by at least 50% after debulking in patients with Sézary syndrome * Disease not appropriate for skin-directed therapy per local institution standards * No disease progression between registration and randomization * No CNS involvement PATIENT CHARACTERISTICS: * WHO performance status 0-2 * Life expectancy \> 12 months * Hemoglobin ≥ 10 g/dL * Absolute neutrophil count ≥ 1.5 x 10\^9/L * Platelet count ≥ 60 x 10\^9/L * Total bilirubin ≤ 1.5 times upper limit of normal (UNL) * Alkaline phosphatase ≤ 3 times UNL * ALT/AST ≤ 3 times UNL * Electrolytes (including sodium, potassium, and chloride) normal * Creatinine normal * Creatinine clearance ≥ 60 mL/min * Uric acid and calcium normal * Free T4 and TSH ≤ 1.5 times ULN * Patients with a buffer range from the normal values of +/- 10% for hematology and biochemistry are acceptable * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception 4 weeks prior to, during, and for 4 weeks after completion of study therapy * Males must agree not to donate semen during and for 1 week after completion of study therapy * Patients with high risk for or history of a thromboembolic event must agree to receive prophylactic anticoagulation therapy (e.g., vitamin K) to keep INR in the range of 2-3 * No New York Heart Association class III-IV disease * No blood donating during and for 1 week after completion of study therapy * No uncontrolled infectious disease, autoimmune disease, or immunodeficiency * No second malignancies within the past 3 years except surgically cured carcinoma in situ of the cervix, in situ breast cancer, incidental finding of stage T1a or T1b prostate cancer, and basal or squamous cell carcinoma of the skin * No psychological, familial, sociological, or geographical condition potentially hampering compliance with the study protocol and follow-up schedule * No Lapp lactase deficiency or history of glucose-galactose malabsorption PRIOR CONCURRENT THERAPY: * See Disease Characteristics * No other prior intravenous chemotherapy for this cancer * For purposes of this protocol, the definition of intravenous chemotherapy also includes denileukin diftitox, antibodies, or antibody conjugates * No prior splenectomy or splenic irradiation * No concurrent topical corticosteroids * Concurrent systemic corticosteroids allowed for treatment of tumor flare reactions * No radiation or drug-based therapy (including steroids) between registration and randomization * No other concurrent drugs (including steroids) during the debulking regimen * Low-dose steroids as premedication allowed at the investigator's discretion * No other concurrent anticancer treatments