Rituximab and Combination Chemotherapy in Treating Patients With Primary Central Nervous System Lymphoma

Inclusion criteria:

* Histologically confirmed non-Hodgkin's lymphoma by brain biopsy
* Patients with inconclusive biopsy or patients who are not candidates for biopsy must have typical CT scan or MRI of the brain AND meet ≥ 1 of the following criteria:

* Positive cerebrospinal fluid cytology for lymphoma OR a monoclonal lymphoid population as defined by cell surface markers or immunoglobulin gene rearrangement studies
* Biopsy-proven involvement of the vitreous or uvea if cells are apparent in the posterior chamber or vitreous by ophthalmological examination
* Bideminsionally measurable disease, defined as contrast-enhancing tumor ≥ 1 cm by pretreatment MRI/CT scan

* Meningeal or vitreous involvement constitutes evaluable but not measurable disease
* If an excisional, rather than a needle biopsy was done, measurable disease must be present on a postoperative scan (not a PET-CT scan)
* ECOG performance status 0-3
* Absolute granulocyte count ≥ 1,500/mm³
* Platelet count ≥ 100,000/mm³
* Bilirubin ≤ upper limit of normal (ULN)
* SGOT ≤ 2.0 times ULN
* Creatinine clearance ≥ 50 mL/min
* Negative pregnancy test
* Fertile patients must use effective contraception

Exclusion criteria:

* Pregnant or nursing
* HIV-1 positivity
* Other malignancy within the past 5 years except basal cell skin cancer or any carcinoma in situ
* Pre-existing immunodeficiency
* Hepatitis B surface antigen positivity
* Systemic lymphoma (as determined by pre-registration CT scans and physical examination)
* Prior chemotherapy or radiotherapy for primary central nervous system lymphoma
* Prior organ or bone marrow transplantation