Treatment for primary CNS lymphoma: the next step

The use of preradiotherapy (RT) methotrexate (MTX) has improved disease control and survival in patients with primary CNS lymphoma (PCNSL). The reported protocol was designed to optimize and enhance the chemotherapeutic component of treatment.

Fifty-two patients were treated with five cycles of high-dose MTX 3.5 g/m(2), procarbazine 100 mg/m(2)/d, and vincristine 1.4 mg/m(2). Thirty patients received whole-brain RT (45 Gy). Twenty-two older patients deferred RT to diminish the risk of delayed neurotoxicity; these patients are compared with 12 older patients who completed the entire treatment regimen. Most patients (n = 35) received high-dose cytarabine after RT.

Objective response rate to the induction chemotherapy regimen was 90%; overall median survival is 60 months. Grade 3 or 4 myelosuppression was seen in 30 patients, primarily in association with cytarabine; grade 3 nephrotoxicity due to MTX was seen in two patients. Older patients had similar median survival with or without the addition of RT: 32 versus 33 months, respectively. However, late neurotoxicity was significantly more common in those older patients who received RT (P: =.00004). Patients younger than 60 years who received the complete treatment regimen have not reached median disease-free or overall survival.

Increasing the dose of MTX and adding procarbazine and vincristine improved disease control and overall survival in patients with newly diagnosed PCNSL. Younger patients in particular fared extremely well with this treatment regimen. In older patients, deferring whole-brain RT did not compromise overall survival but did reduce treatment-related toxicity.