Combined modality therapy for primary CNS lymphoma

Primary CNS lymphoma (PCNSL), formerly rare, is being seen with increased frequency among apparently immunocompetent patients. Conventional treatment has consisted of whole-brain radiotherapy (RT) and corticosteroids, with a median survival of 15 to 18 months and a 3% to 4% 5-year survival. Chemotherapy has been useful in the treatment of recurrent PCNSL. In 1985 we began a treatment protocol using chemotherapy and cranial irradiation for the initial therapy of non-AIDS PCNSL.

Thirty-one patients (group A) completed the combined modality regimen. All had placement of an Ommaya reservoir and received pre-RT systemic methotrexate, 1 g/m2, plus six doses of intra-Ommaya methotrexate at 12 mg per dose. A full course of cranial RT (4,000-cGy whole-brain RT plus a 1,440-cGy boost) was followed by two cycles of high-dose cytarabine (ara-C), with each course consisting of two doses of 3 g/m2 ara-C separated by 24 hours and infused over 3 hours. During this period, 16 additional patients (group R) were treated with RT alone, either because patients refused chemotherapy or RT was initiated before our consultation; all would have been eligible to participate in the protocol. Follow-up extended through April 1, 1991.

Group A had a significantly prolonged time to recurrence (median, 41 months) compared with group R (median, 10 months; P = .003). Although median survival was doubled from 21.7 months for group R to 42.5 months for group A, this was not statistically significant because of small sample size. More importantly, group R patients received systemic chemotherapy for recurrent PCNSL, which improved survival.

The addition of chemotherapy to cranial RT for initial treatment of PCNSL significantly improved disease-free survival and contributed to overall survival; all non-AIDS patients with newly diagnosed PCNSL should be considered for combined modality therapy.