The purpose of this study is to find out if immunotherapy (rituximab) added to chemotherapy is a safe treatment for primary central nervous system lymphoma (PCNSL). PCNSL is a rare tumor. It is usually treated with chemotherapy and radiation. This combination prolongs survival, but about half of patients relapse. The investigators hope that the addition of rituximab will improve the control of the tumor.

The purpose of this study is to find out if immunotherapy (rituximab) added to chemotherapy is a safe treatment for primary central nervous system lymphoma (PCNSL). PCNSL is a rare tumor. It is usually treated with chemotherapy and radiation. This combination prolongs survival, but about half of patients relapse. We hope that the addition of rituximab will improve the control of your tumor.

The second goal of this study is to assess a lower dose of brain radiation. Brain radiation may cause memory loss or dementia. For patients over the age of 60, the risk of significant memory loss is 80-90%. The risk for younger patients is smaller but less clear. In this, study patients whose tumors are in remission after chemotherapy will be treated with a lower dose of brain radiation. We hope that this lower dose will be less toxic. However, it is also possible that using a lower dose of radiation will be less effective in controlling your tumor.

Inclusion Criteria:

• All patients must have a histologic diagnosis of non-Hodgkin's lymphoma by brain biopsy. Patients who have an inconclusive biopsy or who are not candidates for biopsy may be eligible provided they have a typical cranial magnetic resonance imaging (MRI) or computed tomography (CT) scan and meet at least one of the following two criteria:

  • A positive cerebrospinal fluid (CSF) cytology for lymphoma or a monoclonal lymphocyte population as defined by cell surface markers
  • A biopsy of the vitreous or uvea demonstrating non-Hodgkin's lymphoma

• A typical MRI/CT scan for primary intracranial lymphoma is defined as the presence of hypo, iso, or hyperdense parenchymal contrast-enhancing (usually homogeneously) mass lesion(s)

• Patients must be HIV-1 negative

• Patients must have a normal or negative pre-treatment systemic evaluation including:

  • A bone marrow aspirate and biopsy
  • CT scans of the chest, abdomen and pelvis
  • Patients must have adequate bone marrow function (defined as peripheral leucocyte count > 4000 cells/mm3 and platelet count > 100,000 cells/mm3), liver function (bilirubin < 2.0 mg and SGOT < 2 times upper limit of normal), and adequate renal function (serum creatinine < 1.5 mg/dl or creatinine clearance > 50 cc/min/1.73M2)

• Men and women of reproductive potential must agree to use an acceptable method of birth control during treatment and for six months after completion of treatment

Exclusion Criteria:

The following would exclude a patient from the study:

• Prior cranial irradiation
• Other active primary malignancy with the exception of basal cell carcinoma of the skin and cervical carcinoma in situ
• Pre-existing immunodeficiency such as renal transplant recipient
• Prior treatment with chemotherapy for CNS lymphoma