Cognitive outcomes and long-term follow-up results after enhanced chemotherapy delivery for primary central nervous system lymphoma

Patients with non-acquired immunodeficiency syndrome-related primary central nervous system lymphomas have the potential to achieve durable complete responses without radiotherapy, with treatment using enhanced chemotherapy delivery with blood-brain barrier disruption (BBBD). Reported 5-year survival rates with combined chemotherapy and radiotherapy were generally only 9 to 22% and were associated, in one study, with an overall 32% incidence of overt dementia and ataxia, which are dramatically increased among patients more than 60 years of age.

At the Oregon Health Sciences University, 111 consecutive patients with non-acquired immunodeficiency syndrome-related central nervous system lymphomas were prospectively treated with methotrexate-based, BBBD-enhanced chemotherapy and underwent formal neuropsychological evaluations. Of those, 74 patients had no systemic lymphoma and had received no prior irradiation; those 74 patients are described in this report.

The estimated 5-year survival rate for this group was 42%, and the median survival time was 40.7 months. Overall, 48 patients (65%) exhibited complete responses and 36 patients continued to exhibit complete responses after 1 year of BBBD-enhanced chemotherapy. Of those 36 patients, none demonstrated evidence of cognitive loss in neuropsychological tests and/or clinical examinations.

BBBD-enhanced chemotherapy delivery, without subsequent radiotherapy, resulted in favorable survival and cognitive outcomes for patients with primary central nervous system lymphomas who had not previously undergone irradiation. A cooperative multicenter study of intravenous chemotherapy without radiotherapy versus BBBD-enhanced chemotherapy would address the feasibility and necessity of performing a Phase III study for these rare central nervous system malignancies.