Primary non-Hodgkin's lymphoma of the central nervous system. Results of radiotherapy in 15 cases.

Primary non-Hodgkin's lymphoma (NHL) of the central nervous system is a rare disease. The number of cases reported in the literature does not exceed 200. The current series comprises 15 cases of primary NHL of the CNS. In 12 cases material for pathology was obtained at surgery. In the other three cases the diagnosis was established by cytologic examination of the cerebrospinal fluid (CSF). The type of lymphoma was predominantly the diffuse lymphocytic type. All the patients received irradiation on the whole brain by means of two opposite lateral fields. The administered total doses were 40 Gy in four weeks in ten cases, 50 to 60 Gy in 5 to 6 weeks in four cases and 30 Gy in three weeks in one case. All but three patients are dead although initially a good tumor response was obtained as confirmed in most of the cases by CT scan. The mean survival of the dead patients was 14.5 months. No relationship was found between the administered dose and the relapse-free time. In six cases (40%) evidence of seeding was observed. Because of the poor results obtained with irradiation either of only the tumor bearing area or whole brain and because of the high risk of seeding through the CSF, the irradiation of the entire CNS is recommended in patients with primary NHL of the brain.