Advances in the therapy of primary central nervous system lymphoma

Association of genetic variants of methionine metabolism with methotrexate-induced CNS white matter changes in patients with primary CNS lymphoma

Methotrexate (MTX) is an important anticancer drug and the most efficient chemotherapy component in primary CNS lymphoma (PCNSL). A typical side effect of intravenous high-dose MTX is the occurrence of confluent CNS white matter changes (WMC). Because MTX directly interferes with methionine metabolism, we analyzed the impact of genetic variants of methionine metabolism on the occurrence of WMC as a model of MTX toxicity. In a retrospective analysis of 68 PCNSL patients treated with MTX-based polychemotherapy with (n = 42) or without (n = 26) intraventricular treatment, 10 genetic variants influencing methionine metabolism were analyzed. Pearson's chi(2) test and multinominal regression analysis were used to define the relevance of these genetic variants for the occurrence of WMC. In this patient sample, the occurrence of WMC was significantly predicted by the TT genotype of methylenetetrahydrofolate reductase c.677C>T (chi(2) = 8.67; p = 0.013; df = 2), the AA genotype of methylenetetrahydrofolate reductase c.1298A>C (chi(2) = 13.5; p = 0.001; df = 2), and the GG genotype of transcobalamin 2 c.776C>G (chi(2) = 19.73; p < 0.001), in addition to male gender (chi(2) = 11.95; p = 0.001). These data strengthen the hypothesis that MTX effects are influenced by methionine metabolism, which may offer new strategies to improve MTX-based therapies.

Complete response to temozolomide treatment in an elderly patient with recurrent primary central nervous system lymphoma--case report

An 80-year-old woman presented with primary central nervous system (CNS) lymphoma manifesting as progressive disorientation and loss of activity. She received three cycles of high-dose methotrexate. The tumor shrank after two cycles and her mental status improved, but she suffered tumor recurrence. The second-line treatment consisted of four cycles of rituximab but the tumor enlarged. She was then treated with three cycles of temozolomide. Magnetic resonance imaging revealed no evidence of disease. Her mental status and performance status improved, and she suffered no toxicity. She is able to pursue her daily life without recurrence after 16 cycles of temozolomide. Temozolomide may be effective against relapsed primary CNS lymphoma without causing neurotoxicity in the elderly.

Ocular adnexal lymphoma: a review of clinicopathologic features and treatment options

The recent literature shows that interest in ocular adnexal lymphomas and their biologic and clinical characteristics—along with their possible association with Chlamydia psittaci infection and therapeutic management with rituximab or anti-Chlamydia psittaci antibiotic therapy—is considerable. These new data have modified the previously reported features of this disease and have made an updated review of the literature necessary. The aims of this review are to present the current knowledge on the biology of these lymphomas, their clinical features and prognostic factors, and the panel of all available treatment options.

Treatment of relapsed central nervous system lymphoma with high-dose methotrexate

PURPOSE

Over the past decade, high-dose methotrexate has emerged as the single most effective agent in the initial treatment of primary nervous system lymphoma. However, the majority of patients who respond initially to treatment relapse. The optimal management of these patients has not been determined. We performed a multicenter, retrospective study of high-dose methotrexate in patients with relapsed central nervous system lymphoma.

EXPERIMENTAL DESIGN

Patients with relapsed disease were eligible if they achieved a complete response to initial treatment with methotrexate-based chemotherapy or received methotrexate after gross total resection or interstitial radiation. All of the patients were retreated with a regimen containing high-dose methotrexate (>/=3 g/m(2)).

RESULTS

Twenty-two patients with a median age of 58 years were included in the study. Overall response rates were 91% to first salvage (20 of 22 patients) and 100% to second salvage (4 of 4 patients). Median survival was 61.9 months after first relapse (95% confidence interval, 42.1- infinity ) and 91.9 months overall (95% confidence interval, 47.2- infinity ). Toxicity was primarily hematologic with 10 episodes of grade 3 or 4 toxicity during 566 cycles of chemotherapy.

CONCLUSIONS

These results indicate that high-dose methotrexate remains effective for relapsed central nervous system lymphoma in patients who initially respond to methotrexate and raise the possibility of deferring more toxic salvage regimens in this select group of patients.

Leptomeningeal metastases

LM is an increasingly common neurologic complication of cancer with variable clinical manifestations. Although there are no curative treatments, currently available therapies can preserve neurologic function and potentially improve quality of life. Further research into the mechanisms of leptomeningeal metastasis will elucidate molecular and cellular pathways that may allow identification of potential targets to interrupt this process early or to prevent this complication. Animal models are needed to further define the pathophysiology of LM and to provide an experimental system to test novel treatments [242-245]. There is an urgent need to develop new drug-based or radiation-based treatments for patients with LM. Randomized clinical trials are the appropriate study design to determine the efficacy of new treatments for LM. However, surrogate markers for response must be developed to facilitate the identification of effective regimens. Survival is not the optimal end point for such studies as most patients who develop this complication already have advanced, incurable cancer. Prevention of or delay in neurologic progression is one objective that has been utilized in recent randomized trials in patients with LM, and this end point deserves further attention. Although the development of LM represents a poor prognostic marker in patients with cancer it is important for physicians to recognize the symptoms and signs of the disease and establish the diagnosis as early in the disease course as possible. This may provide an opportunity for effective intervention that can improve quality of life, prevent further neurologic deterioration and, for a subset of patients, improve survival.