Involvement of the central nervous system by non‐Hodgkin's lymphoma. The southwest oncology group experience

Fifty (5%) of 1039 patients with non-Hodgkin's lymphomas registered on two Southwest Oncology Group clinical trials between 1972 and 1977 developed evidence of central nervous system (CNS) lymphoma. Thirty-nine patients (3.7%) had leptomeningeal involvement, 10 patients (1%) had focal cerebral involvement and 2 patients (0.1%) had spinal cord compression. Cytologic examination of the cerebrospinal fluid (CSF) was the most reliable diagnostic technique. Patients with diffuse histologies and those with nodular histiocytic lymphoma had the highest incidence of CNS disease. Diffuse histiocytic lymphoma accounted for 22 patients with CNS involvement. Lymphoblastic lymphoma, convoluted type, was found in 6 patients, although in none was the diagnosis established prospectively. Patients who developed CNS lymphoma usually had extranodal disease and systemic symptoms at initial staging (90% stage IV, 54% “B” symptoms). The most commonly involved extranodal sites included the bone marrow (56%), gastrointestinal tract (26%), skin (18%), and lung (14%). CNS lymphoma was observed at all times during the clinical course but was most common in patients with active, poorly controlled disease. In 13 patients (26%), however, CNS lymphoma was the first sign of relapsing lymphoma. Median survival after recognition of CNS lymphoma was 2 months. The incidence of CNS disease was similar for 5 remission induction regimens employed, but maintenance chemotherapy with vincristine, prednisone and parenteral cytosine arabinoside appeared to substantially reduce the incidence of late CNS relapse (1 of 90 patients) compared to maintenance treatment with oral cyclophosphamide in place of cytosine arabinoside (9 of 90 patients, p = 0.02). This study indicates that there is a subgroup of patients with readily identifiable clinical and pathologic features who might benefit from prophylactic therapy to prevent CNS lymphoma.