WFNO/SNO Abstracts

BACKGROUND: The treatment of patients with primary CNS lymphomas (PCNSL) has dramatically changed since the 1970’s when whole brain radiation generated median survivals of about 12 months, significant neurotoxcity, and few long term survivors. High dose methotrexate (HD-MTX) monotherapy without radiation provides excellent response rates and 30% long term survivors without neurotoxicity. In general, relapses occur in the first two to four years after diagnosis and reports of very late relapses are rare. METHODS: Charts of all patients treated with HD-MTX monotherapy for newly diagnosed PCNSL between 1995 and 2012 at The Johns Hopkins Hospital were reviewed retrospectively. Patients with less than 5 years of follow-up data were excluded. First relapses over 10 years from diagnosis were identified and reviewed. RESULTS: Long-term follow-up data was available for 37 patients treated with HD-MTX monotherapy during this period. Four of 37 (11%) survived disease free for .10 years from initial diagnosis and maintain their excellent clinical status. All received methotrexate (8 gm/ m 2 ) every two weeks until complete response and then monthly to complete one year of therapy. Two of these long survivors (50%) presented with new seizures 10.8 and 11.2 years after initial diagnosis. Imaging revealed recurrent intraparenchymal disease, re-biopsy confirmed PCNSL in one, and both responded very well to retreatment with high dose methotrexate and Rituximab. The other two patients remain relapse free 12 and 13.7 years after initial diagnosis. CONCLUSION: Very late relapses have occurred in 2 of 4 long term survivors. These observations suggest that PCNSL patients treated with HD-MTX who were considered cured may be at substantial risk for late recurrences. A concerted effort to follow patients with this rare disease is needed to determine the frequency of late recurrences. More information is needed to determine if the addition of rituximab or other therapies reduce late recurrence rates.