Population-based experience on primary central nervous system lymphoma 2000-2012: the incidence is increasing

Background: Primary central nervous system lymphomas (PCNSL) are rare lymphomas with a poor prognosis. Recently, an increased incidence has been reported. The present study is a population-based study of all patients with PCNSL in the Uppsala/orebro region of middle Sweden.Patients and methods: All patients diagnosed with a PCNSL at Uppsala University Hospital 2000-2012 were identified. Altogether, 96 patients (50 women and 46 men) were included. The median age at diagnosis was 66 years (17-95).Results: There was a statistically significant increase in age-standardized incidence during the study period, 30 patients were diagnosed in the first half and 66 in the second half of the period. No patient had an HIV-infection. Two patients had undergone kidney transplantation and were treated with immunosuppressive drugs. A high proportion of the patients, 29%, had a history of an autoimmune or inflammatory disease. The prognosis was poor with a median survival of only four months. In the 70 (73%) patients treated with curative intention the median survival was 12 months. Patients treated with high-dose methotrexate, radiotherapy and/or temozolomide appeared to have a better survival. There was no improvement in survival during the study period or after the introduction of rituximab. There also was no difference in any of the analyzed variables that could explain the increased incidence.Conclusion: In this population-based study we could confirm the previously described increased incidence of PCNSL. The prognosis remains poor despite the inclusion of treatment with rituximab during the study period. A high proportion of the patients had a history of an autoimmune or inflammatory disease not previously described but there was no increase during the study period.