High-dose methotrexate toxicity in elderly patients with primary central nervous system lymphoma

Background: The dose of high-dose methotrexate (HDMTX) in elderly patients often has to be reduced, resulting in a loss of treatment efficacy. We evaluated HDMTX-related toxicity with special regard to age distribution in patients with primary central nervous system lymphoma (PCNSL) in a phase IV multicenter trial. Patients and methods: One hundred and fifty-four patients (median age 61 years; 89 patients >60 years old, 21 patients >70 years old) received 619 HDMTX cycles. Toxicity was evaluated prospectively using the WHO classification. Unless a reduced dose was required after calculating a decreased glomerular filtration rate (GFR), the patients received 4 g/m(2) HDMTX followed by leucovorin rescue. Results: Toxicity was generally mild with toxicities of WHO grade >= 3 usually <10%. The differences in the incidence and severity of toxicity were not statistically significant between patients >60 years and ! 60 years old. The same was true for therapy termination owing to MTX toxicity and for delayed serum MTX clearance. Dose reduction significantly differed between patients <= 60 years and those >60 years old (18% versus 44%; P=0.001). Conclusions: HDMTX is a safe treatment for PCNSL patients regardless of age, with adherence to dose reduction determined by calculating the GFR before each treatment cycle.