CNS involvement in small noncleaved-cell lymphoma: is CNS disease per se a poor prognostic sign?

Of 120 patients with small noncleaved-cell lymphoma who were entered sequentially on four National Cancer Institute (NCI) protocols, 29 (24%) had CNS involvement at some time in their clinical course. Seventeen had initial CNS involvement, and 12 developed CNS involvement at the time of first relapse. All 29 patients had extensive disease at presentation. The median serum lactate dehydrogenase (LDH) levels at presentation were 1,150 IU/L for patients with initial CNS involvement and 1,083 IU/L for patients with CNS involvement at relapse. CNS disease was significantly associated with serum LDH levels (P less than .0001), bone marrow involvement (P less than .0001), and jaw involvement (P = .018), but not involvement of the abdomen. There were nine long-term survivors among the 29 patients (31%). CNS disease did not appear to confer a worse prognosis on these patients than on patients without CNS involvement who had similar degrees of serum LDH elevation or who had bone marrow involvement, suggesting that extensive disease rather than CNS involvement was responsible for the poor prognosis. Event-free survival for patients with serum LDH levels above 500 IU/L was not different whether CNS disease was present or not (P = .29), nor was event-free survival different for patients with stage IV disease, whether CNS disease was present or not (P = .92). Although some patients had CNS radiation, there was no evidence that this was of therapeutic benefit. Intrathecal (IT) chemoprophylaxis effectively prevented spread to the CNS in patients without initial CNS involvement. Five of 18 patients (28%) who received no IT prophylaxis had CNS relapse (four isolated to the CNS), but only seven of the 85 patients (8%) who received IT prophylaxis had CNS relapse (two isolated to the CNS). The differences in overall and isolated CNS relapse rates were statistically significant (P = .034 and P = .008, respectively).