PCV salvage chemotherapy for recurrent primary CNS lymphoma

Chemotherapy for primary central nervous system lymphoma

✓Chemotherapy, with or without radiotherapy, is the mainstay of treatment for primary central nervous system lymphoma (PCNSL). High-dose methotrexate (MTX) is the most effective drug available to treat these lesions, and it is used in doses of 1 to 8 g/m2, either as a single agent or in combination with other drugs such as corticosteroid agents, cytarabine, procarbazine, vincristine, carmustine, lomustine, thiotepa, cyclophosphamide, temozolomide, and rituximab. To date, an overwhelming number of different regimens in which high-dose MTX is used have been reported. Given the lack of randomized trials, however, the optimal treatment remains controversial. Varying methodology makes the comparison of available studies extremely difficult, yet some common themes can be found throughout the literature. Treatment paradigms vary considerably according to the patient's age. Most studies support the use of chemotherapy-only treatments for elderly patients (> 60 years), given the high risks of neurotoxicity associated with radiotherapy. Nevertheless, the prognosis remains poor regardless of the chemotherapy chosen, and less toxic regimens might be preferable for such elderly patients. Conversely, in younger patients (< 60 years), there is growing evidence that commonly used chemotherapy-only regimens are associated with increased relapse rates that may not justify deferral of radiotherapy. Thus, a significant focus of research has been the development of intensified chemotherapy regimens that could replace radiotherapy. In this article, the authors discuss the principles guiding the use of chemotherapy for PCNSL, and critically review the available literature, including the most recent trials.

Temozolomide: a milestone in neuro-oncology and beyond?

Temozolomide (Temodal, Temodar), an imidazol derivative, is a second-generation alkylating agent. The orally available prodrug with the capacity of crossing the blood-brain barrier received accelerated US FDA approval in 1999. Three pivotal Phase II trials showed modest activity in the treatment of recurrent anaplastic astrocytoma glioblastoma. In 2005, the FDA and the European Agency for the Evaluation of Medicinal Products approved temozolomide for use in newly diagnosed glioblastoma, in conjunction with radiotherapy, based on an European Organisation for Research and Treatment of Cancer/National Cancer Institute of Canada Phase III trial. The adverse events associated with temozolomide are mild-to-moderate and generally predictable; the most serious are noncumulative and reversible myelosuppression and, in particular, thrombocytopenia, which occurs in less than 5% of patients. Continuous temozolomide administration is associated with profound CD4-selective lymphocytopenia. Molecular studies have suggested that the benefit of temozolomide chemotherapy is restricted to patients whose tumors have a methylated methylguanine methyltransferase gene promotor and are thus unable to repair some of the chemotherapy-induced DNA damage. Temozolomide is under investigation for other disease entities, in particular lower-grade glioma, brain metastases and melanoma.

Prospective trial on topotecan salvage therapy in primary CNS lymphoma

BACKGROUND

Standard salvage therapy has not been established for recurrent primary central nervous system lymphoma (PCNSL). We report the final results of a prospective study on topotecan chemotherapy in relapsed or refractory PCNSL.

PATIENTS AND METHODS

The study included 27 patients with a median age of 51 years and an ECOG performance status of 2. Fourteen patients were refractory to the last therapy, and 13 relapsed after a median period of 6.0 months. Pretreatment with up to four regimens included chemotherapy in 26 patients and whole brain irradiation in 14. A 30-min daily topotecan infusion of 1.5 mg/m(2) for 5 days was repeated every 3 weeks.

RESULTS

The response rate was 33% with five complete (CR) and four partial remissions (PR). The median follow-up was 37.7 months. All complete responders had sustained remissions lasting for 9 to 28 months. The median event-free survival (EFS) was 2.0 months (9.1 months in responders), the overall survival (OAS) was 8.4 months. CTC grade 3-4 leukopenia occurred in 26% and thrombocytopenia in 11% of the patients. Eight of 12 patients alive without cerebral lymphoma > or = six months after topotecan exhibited deficits attributable to late neurotoxicity.

CONCLUSION

Topotecan as monotherapy is active in relapsed and refractory PCNSL with tolerable toxicity.

Primary CNS lymphoma

Primary CNS lymphoma (PCNSL), an uncommon form of extranodal non-Hodgkin's lymphoma (NHL), has increased in incidence during the last three decades and occurs in both immunocompromised and immunocompetent hosts. PCNSL in immunocompetent patients is associated with unique diagnostic, prognostic, and therapeutic issues, and the management of this malignancy is different from that of other forms of extranodal NHL. Characteristic imaging features should be suggestive of the diagnosis, avoidance of corticosteroids, if possible, and early neurosurgical consultation for stereotactic biopsy. Because PCNSL may involve the brain, CSF, and eyes, diagnostic evaluation should include assessment of all of these regions as well as screening for possible occult systemic disease. Resection provides no therapeutic benefit and should be reserved for the rare patient with neurologic deterioration due to brain herniation. Whole-brain radiation therapy (WBRT) alone is insufficient for durable tumor control and is associated with a high risk of neurotoxicity in patients older than age 60. Neurotoxicity typically is associated with significant cognitive, motor, and autonomic dysfunction, and has a negative impact on quality of life. Chemotherapy and WBRT together improve tumor response rates and survival compared with WBRT alone. Methotrexate-based multiagent chemotherapy without WBRT is associated with similar tumor response rates and survival compared with regimens that include WBRT, although controlled trials have not been performed. The risk of neurotoxicity is lower in patients treated with chemotherapy alone.

Primary Lymphoma of the Nervous System

This review article provides guidelines for the diagnosis, staging, and management of primary nervous system lymphoma based on the results of clinical trials conducted during the last decade. Recent progress in our understanding of the pathogenesis of primary nervous system lymphoma is summarized, and implications of these findings for the development of diagnostic tools and new therapeutic strategies are outlined. We performed a search of the PubMed database (National Center for Biotechnology Information) for articles on primary nervous system lymphoma published between 1970 and May 2005. Primary nervous system lymphoma affects the brain, eye, and meninges as well as cranial, spinal, and peripheral nerves. Although important lessons have been learned from the pathogenesis of extraneural non-Hodgkin's lymphoma, the unique organotropism of primary nervous system lymphoma remains poorly understood. Diagnosis is facilitated by modern imaging techniques and molecular markers. Clinically recognizable "precursors" may exist but frequently elude specific diagnosis. Insight into the peculiar pharmacokinetics of chemotherapy aimed at tumors within the nervous system has led to the development of methotrexate-based regimens that can achieve prolonged progression-free survival without the use of radiation. Long-term survival and, in selected cases, even a cure are possible in primary nervous system lymphoma. Treatment should be provided in specialized multidisciplinary centers. In spite of remarkable progress through methotrexate-based chemotherapy, the majority of patients experience relapse within a few years. Better diagnostic tools are required for earlier diagnosis and monitoring of treatment response. A deeper understanding of the pathogenesis of primary nervous system lymphoma may reveal new therapeutic targets.

Primary central nervous system lymphoma

Primary central nervous system lymphoma is a stage 1E non-Hodgkin's lymphoma confined to the nervous system. It is seen in immunocompetent and immunodeficient populations, the latter group associated with the Epstein-Barr virus. Primary central nervous system lymphoma can affect the brain, leptomeninges, spinal cord or eyes. The institution of high-dose methotrexate-based regimens and whole-brain radiation therapy has significantly increased survival, but neurotoxicity is high in patients over 60 years of age. Despite these advances, 50% of patients initially treated will relapse. Recent investigations include the use of rituximab (immunotherapy) and stem-cell transplantation, as well as regimens without whole-brain radiation therapy in the elderly. The optimal treatment regimen is yet to been determined.

NOA-03 trial of high-dose methotrexate in primary central nervous system lymphoma: final report

The NOA-03 trial explored high-dose methotrexate alone in 37 patients with primary central nervous system lymphoma. The overall median survival was 25 months. After 4 years, the rate of leukoencephalopathy in patients surviving more than 12 months was 58% with and 10% without whole-brain radiotherapy given at relapse (p = 0.11). Attention deficits were found in all six tested patients, and memory deficits in four patients. Two patients had normal, three had moderately restricted, and one had markedly restricted quality of life. Thus, high-dose methotrexate with deferred radiotherapy had only moderate efficacy and was associated with significant neurotoxicity in long-term surviving patients.

Monoclonal antibody therapy for central nervous system lymphomas: an emerging treatment paradigm

The management of CNS lymphomas is poised for another revolution due to the emergence of therapeutic monoclonal antibodies. As the technology for generating monoclonal antibodies matures and obstacles are solved, therapeutic monoclonal antibodies will play an increasing role in the management of cancer. This article will review the biology of CNS lymphomas, monoclonal antibody technology, limitation of existing chemotherapies and the application of therapeutic monoclonal antibodies for the treatment of CNS lymphomas.

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.

Diagnosis and treatment of primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is an uncommon form of non-Hodgkin's lymphoma (NHL) that has been increasing in incidence over the past three decades. Unlike systemic extranodal NHL, the response to therapy for PCNSL patients has been somewhat unsatisfactory. However, methotrexate-based chemotherapy and whole-brain radiotherapy have improved the outcome of patients. Unfortunately, treatment-related neurotoxicity is common, especially in the elderly. Although progress has been made in treating PCNSL, there remains no optimal methotrexate dose or frequency. Treatment of recurrence also remains controversial. These important questions have prompted several clinical studies looking at novel ways to intensify chemotherapy and limit neurotoxicity.

The treatment of primary central nervous system lymphoma in 122 immunocompetent patients

BACKGROUND

The objective of this study was to evaluate the clinical outcome of a population-based cohort of immunocompetent patients with primary central nervous system lymphoma (PCNSL) treated with 3 different strategies over 13 years.

METHODS

One hundred twenty-two consecutive patients (median age, 66 years) with PCNSL were identified. Three treatment strategies were employed: 1) whole-brain irradiation with (from January, 1990, to June, 1991) or without (from April, 1995, to December, 1999) cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP)-type chemotherapy (n=50 patients); 2) combined-modality therapy, including 1 g/m2 methotrexate plus whole-brain irradiation (from July, 1991, to March, 1995; n=34 patients); and 3) 8 g/m2 methotrexate alone (from January, 2000, to March, 2003) with whole-brain irradiation reserved for those with progressive disease (n=38 patients). Treatment failure was defined as progressive disease, disease recurrence, death from toxicity or lymphoma, or toxicity that necessitated a change in primary treatment.

RESULTS

The median failure-free survival was 7 months, and the median overall survival (OS) was 17 months. The median OS was similar in all 3 eras. In this population-based analysis, one-third of patients did not receive the treatment strategy of the era. Therefore, the data also were analyzed by treatment received. On multivariate analysis (including era of treatment), 3 factors-age > 60 years, lactate dehydrogenase > normal, and omission of methotrexate-were associated significantly with poorer OS (hazard ratio: 2.3, 2.2, and 2.3, respectively).

CONCLUSIONS

Outcomes for a general population with PCNSL remained constant despite different treatment strategies over three eras. For the two-thirds of patients who could receive potentially curative treatment, age, lactate dehydrogenase level, and receipt of > or = 1 g/m2 methotrexate appeared to be important determinants of OS.

Treatment of primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is a rare neoplasm that has captured popular attention because of its rising incidence and marked chemosensitivity. It is a non-Hodgkins B-cell lymphoma (NHL) that appears confined to the central nervous system (CNS) at presentation but may be multifocal within the brain or involve the leptomeninges or eyes at diagnosis. Like systemic lymphoma, it is highly sensitive to corticosteroids, and administration of steroids should be withheld until the diagnosis has been confirmed histologically. Currently, the initial treatment of choice incorporates high-dose methotrexate (HD-MTX) either as a single agent or in combination with other systemic chemotherapies. Whole-brain radiotherapy (WBRT) can be a highly effective treatment modality when combined with MTX, but the combination causes an unacceptably high incidence of severe permanent neurotoxicity, particularly in patients over age 60. Therefore, chemotherapy alone is the initial treatment of choice in older patients. This approach is also being explored in younger patients, but it is possible that deferring radiotherapy may compromise disease control. Consequently, the role of radiotherapy remains to be clarified in newly diagnosed younger patients with PCNSL.

Leptomeningeal metastasis: survival and prognostic factors in 155 patients

In this single-center retrospective study, 155 consecutive patients with leptomeningeal metastasis (LM) were analyzed for the prognostic role of patient- and therapy-related variables. Ten percent of the patients received radiotherapy alone, 32% had chemotherapy alone, 31% received radiochemotherapy, 17% had supportive therapy only, and 10% were not evaluable for therapy. Chemotherapy was systemic (17%), combined systemic and intrathecal (10%), or intrathecal only (35%). Clinical improvement was noted in 41% of the patients. Overall median survival time (MST) was 4.8 months. Survival varied considerably depending on the type of primary tumor in this largest published cohort of LM patients. Univariate Cox regression analysis revealed that age >60 and elevated cerebrospinal fluid (CSF) albumin or lactate levels were therapy-independent predictors of poor survival in the entire cohort as well as in the subgroup of patients with systemic primary tumors (n=105). The assessment of three therapy-independent parameters allows to group LM patients into groups of low, intermediate, and high risk of poor survival. Moreover, the application of systemic chemotherapy was a positive prognostic factor in patients with subarachnoid lesions detected by neuroimaging (RR 1.94, p=0.001) or with extra-CNS tumor deposits (RR 1.52, p=0.05). The results of this study suggest that systemic chemotherapy alone or in combination with other therapeutic modalities may improve outcome in patients with subarachnoid tumor cell deposits detectable by neuroimaging.

Primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is a rare variant of non-Hodgkin's lymphoma that is increasing in incidence. Methotrexate-based chemotherapy in combination with whole-brain radiotherapy (WBRT) has dramatically improved the outcome of patients. However, treatment-related neurotoxicity is a significant complication, especially after radiotherapy in the elderly. Despite advances in therapy, several important questions remain regarding optimal methotrexate dose, dosing frequency, adjunct chemotherapy, and the impact of deferring WBRT. Advances in biologic therapy and strategies to intensify the delivery of chemotherapy may help to limit the use of radiotherapy, thus lessening potential neurotoxicity. Studies looking at oncogenic proteins as potential prognostic markers for PCNSL may help us to develop risk-adapted therapies.

Immunochemotherapy with rituximab and temozolomide for central nervous system lymphomas

BACKGROUND

Methotrexate-based and alkylator-based chemotherapy regimens are associated with renal and bone marrow toxicities, which limit their use in patients with central nervous system (CNS) lymphomas. The authors report their experience with an immunochemotherapy regimen consisting of rituximab and temozolomide in patients with primary or metastatic CNS lymphoma.

METHODS

Seven patients who had received rituximab and temozolomide were identified from the database of the brain tumor clinic at the authors' institution: three patients had developed recurrent primary CNS lymphoma (PCNSL), one patient had newly diagnosed PCNSL but had poor renal function, and three other patients with systemic non-Hodgkin lymphoma developed recurrent lymphoma in the brain only. Patients were scheduled to receive 4 cycles of induction rituximab on Day 1 and temozolomide on Days 1-5 of a 28-day cycle. Thereafter, their treatment included a total of up to 8 maintenance cycles of temozolomide alone on Days 1-5 of a 28-day cycle. A gadolinium-enhanced magnetic resonance image of the head was obtained after every two cycles of treatment.

RESULTS

All patients received rituximab without toxicity. Of the 4 patients who received induction temozolomide at doses > 150 mg/m(2) daily on Days 1-5, 2 experienced Grade 2 leukopenia and thrombocytopenia. Five patients achieved a radiographic complete response, and two patients had partial responses after induction treatment. The median response duration was 6 months (range 3-12+ months), and the median survival was 8 months (range 3+-12+ months).

CONCLUSIONS

Although median survival was short, immunochemotherapy with rituximab and temozolomide was well tolerated and exhibited efficacy in this elderly and heavily pretreated cohort. The data obtained in the current study suggest that the optimal induction dose combination consists of rituximab 375 mg/m(2) on Day 1 and temozolomide 150 mg/m(2) daily on Days 1-5.

Summary statement on primary central nervous system lymphomas from the Eighth International Conference on Malignant Lymphoma, Lugano, Switzerland, June 12 to 15, 2002

Under the sponsorship of the International Extranodal Lymphoma Study Group, a Multidisciplinary Workshop on primary CNS lymphoma (PCNSL) with over 50 participants from Europe, North America, Israel, and Australia was held as part of the Eighth International Conference on Malignant Lymphoma in Lugano, Switzerland (June 12 to 15, 2002). The main purposes of the Workshop were to exchange the latest scientific information, to analyze methodologic issues in the design of clinical trials, to reach a consensus on treatment recommendations and prognostic factors, to discuss clinical and molecular targets for future studies, and to establish an international collaborative group to conduct laboratory and clinical investigations in PCNSL. This article summarizes the contents of the Workshop, analyzes the current knowledge on the most relevant biologic and clinical issues in PCNSL, and focuses on fundamental challenges to be addressed in future studies.

Salvage treatment with etoposide (VP-16), ifosfamide and cytarabine (Ara-C) for patients with recurrent primary central nervous system lymphoma

BACKGROUND

Survival of patients with primary central nervous system lymphoma (PCNSL) has improved with methotrexate-based combination regimens and radiotherapy (RT). However, the prognosis of patients who fail or relapse after initial response is poor. Very little data is available on salvage treatment at recurrence.

PATIENTS AND METHODS

Sixteen immunocompetent patients (13 males/three females, median age 54 yr) with refractory (one patient) or recurrent (15 patients) PCNSL, homogeneously treated at diagnosis with the cyclophosphamide, doxorubicin, vincristine, dexamethasone/carmustine, vincristine, cytarabine and methotrexate (CHOD/BVAM) and RT regimen, received etoposide (VP-16), ifosfamide and cytarabine (Ara-C) (VIA) chemotherapy as a salvage treatment. VIA included etoposide 100 mg/m2/d days 1-3, ifosfamide 1000 mg/m2/d days 1-5, and cytarabine 2000 mg/m2/12 h day 1. The therapy was repeated every 28 d for a total of planned six cycles.

RESULTS

Median time between first complete response (CR) and relapse was 19 months (range: 6-46 months). Thirteen patients (81%) had a performance status <or=2, six had multifocal PCNSL and six (of eight tested) positive cerebrospinal fluid cytology. The median number of courses per patient was four (range: 1-6). Five patients completed the whole VIA therapy. Six patients (37%) achieved CR. After a median follow-up of 15 months for surviving patients, two have relapsed, with a median failure-free survival of 5 months. Twelve patients have died from progression of PCNSL, with a 12-month overall survival of 41% [95% confidence interval (CI): 16-66]. The major toxicity was World Health Organization grade 2-4 neutropenia (69% of patients) and thrombocytopenia (50%). Five patients had grade 3-4 infectious complications. Finally, one patient developed a severe but reversible ifosfamide encephalopathy.

CONCLUSION

The data presented show that the chemotherapy VIA is an effective salvage regimen for patients with recurrent PCNSL.

Case report: a patient with primary CNS lymphoma treated with temozolomide to complete response

We report the case of a 72-year-old woman with primary CNS lymphoma of the mid-brain and pons who had a complete response to oral temozolomide chemotherapy. She initially presented in early 2001 with several weeks of progressive memory loss and unresponsiveness. Because of her age and impaired renal function, she was a poor candidate for whole-brain radiotherapy or systemic high-dose methotrexate. After treatment with two cycles of temozolomide, restaging MRI revealed no evidence of disease. Her mental status improved significantly over this time. Temozolomide may represent a promising new drug for the treatment of primary CNS lymphoma.

Diagnostic advances and new trends for the treatment of primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is a rare non-Hodgkin's lymphoma arising in the brain. Recent increase in its incidence has been noted both in immunocompetent individuals and patients with immunodeficiency. This review will focus on the epidemiology, pathogenesis, diagnosis and treatment of this aggressive extranodal lymphoma in immunocompetent patients. Stereotactic biopsy is usually required for diagnosis, while molecular biology and/or cytofluorimetric analysis may confirm the presence of clonal proliferation in the cerebrospinal fluid (CSF). Methotrexate-based chemotherapy plus whole-brain radiotherapy are the standard treatment for PCNSL and achieve a high rate of complete remissions (CR), but long-term neurotoxicity may heavily compromise the patient's quality of life. The metabolic rate of controversial gadolinium-enhancing lesions on magnetic resonance (MR) scans may be assessed with positron emission tomography (PET), which discriminates radiation necrosis from true recurrence. Withholding radiotherapy in patients achieving CR after first-line chemotherapy is a new and interesting treatment option, while the role of high-dose chemotherapy with stem cell rescue is still uncertain.

Novel chemotherapeutic approaches to brain tumors

In reviewing the numerous investigational drug trials for patients with anaplastic gliomas over the past 20 years, it would be fair to say that there have been more than a few disappointments and that the real impact of many of these therapies on patients' duration and quality of survival has been minor at best. It is also fair to state that there has been progress in developing new types of chemotherapy and other agents, in devising new treatment strategies, and in gaining a deeper understanding of the problems that must be overcome to treat patients with anaplastic gliomas successfully. The past several years have seen the realization that oligodendroglioma, primary CNS lymphoma, and medulloblastoma are sensitive to chemotherapy treatments. It is hoped that future studies will delineate better the optimal use of chemotherapy for these tumors.

Therapeutic management of primary CNS lymphoma in immunocompetent patients

The best therapeutic management in primary CNS lymphomas remains to be defined because of the small size and short follow-up of retrospective series, the methodological pitfalls and limited number of prospective studies, and the paucity of randomized trials. The purpose of this article is to analyze, discuss and summarize the current therapeutic approaches, namely chemotherapy or radiotherapy as exclusive treatment, combined treatment, most commonly used drugs, intrathecal chemotherapy and consolidation radiotherapy and to provide recommendations for ordinary clinical practice. Some important therapeutic issues such as the management of intraocular lymphomas, elderly patients and patients without histological diagnosis, as well as the relevance of salvage therapy as a playground for the evaluation of new drugs are also analyzed. Finally, the main open questions as well as current and expected investigation trends are discussed.

MRI features of primary central nervous system lymphomas at presentation

Pretreatment MRI examinations of 40 immunologically competent patients with primary CNS lymphoma (PCNSL) were evaluated (24 men, 16 women, median age 63 years). Seventy lesions were found (mean size: 19.9 mm). The number of lesions ranged from one (n = 25) to six (n = 1). The most frequent locations were the cerebral hemispheres (n = 22), the corpus callosum (n = 11), and the basal ganglia (n = 11). Cerebellar manifestations were found in 10 patients. Ocular (n = 2) and medullary cord (n = 1) manifestations were rare. Contrast enhancement was encountered in all lesions. Although 39 patients had lesions adjacent to the CSF space, leptomeningeal spread was only present in five patients. Necrosis was seen in two lesions only. Edema was extensive in 24 patients, moderate in 11 patients, and absent in five patients. Contrast-enhancing lesions in contact with the subarachnoid space and without necrosis are characteristic of PCNSL.

Primary nervous-system lymphoma

Primary nervous-system lymphoma is a rare type of non-Hodgkin lymphoma, which is confined to the nervous system. This disease is managed quite differently from the usual treatment of either primary brain tumours or systemic non-Hodgkin lymphoma. Although whole-brain radiotherapy results in responses in more than 90% of cases, this treatment is associated with high relapse rates and with delayed neurotoxicity in elderly patients. First-generation chemotherapy regimens used successfully in systemic non-Hodgkin lymphoma (eg cyclo-phosphamide, adriamycin, vincristine, and prednisone) are ineffective in primary nervous-system lymphoma, partly because of the blood-brain barrier. Median survival of patients treated with radiotherapy alone or chemotherapy plus radiotherapy is similar, and ranges from 10 to 16 months. The addition of methotrexate-based chemotherapy has improved survival for these patients, extending median survival to more than 30 months. When used alone, methotrexate-based chemotherapy is associated with significantly fewer treatment-associated toxic effects. Leptomeningeal lymphoma and intraocular lymphoma are topics of particular relevance in primary nervous-system lymphoma and are addressed in this review.

Advances in the therapy of primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is a rare type of non-Hodgkin's lymphoma (NHL) confined to the nervous system. The management of PCNSL is quite different from the usual treatment of either primary brain tumors or systemic NHL. First-generation chemotherapy regimens used successfully in systemic NHL are ineffective in PCNSL, in large part due to the existence of the blood-brain barrier. Whole-brain radiation therapy (WBRT) results in high response rates but rapid relapse, and this treatment is associated with delayed neurotoxicity in patients with PCNSL. The addition of methotrexate-based chemotherapy has improved survival and lessened toxicity for this patient population. Fundamental issues that remain unresolved in PCNSL include identification of the optimal chemotherapy regimen for newly diagnosed and relapsed PCNSL, the role of WBRT and intrathecal chemotherapy in the treatment of PCNSL, and the optimal management of intraocular lymphoma. Finally, the optimal clinical study design for this rare disease has yet to be defined and implemented.

Primary central nervous system lymphoma 1991-1997: outcome and late adverse effects after combined modality treatment

BACKGROUND

This retrospective single-center study assesses the feasibility, therapeutic outcome, and late side effects of combined modality therapy with intravenous methotrexate, whole brain radiotherapy (WBRT), and intravenous cytarabine in patients with primary central nervous system lymphoma (PCNSL).

METHODS

All 28 consecutive patients diagnosed with PCNSL between 1991 and 1997 were scheduled to receive combined modality therapy. Seven of 28 patients did not receive combined modality treatment: 6 patients had WBRT alone because of poor physical condition, and 1 patient died before receiving treatment. Of the remaining 21 patients, 5 received the complete regimen, and 16 received a modified regimen with reduced dose intensity.

RESULTS

Fourteen of 21 patients (67%) treated with combined modality therapy had a complete response; 1 had a partial response. Median survival was 11 months in all 28 patients, 23 months in all patients with combined modality treatment, and 41 months in patients receiving the complete regimen. Of 15 examinable patients with a follow-up of 8 months or more, 10 developed severely symptomatic and 5 mildly symptomatic or asymptomatic diffuse white matter changes.

CONCLUSION

Only a small subgroup of all patients with PCNSL appears to be eligible for receiving all parts of the combined modality regimen. Treatment in these patients leads to a marked prolongation of survival. The risk of late side effects is high even with modified, dose intensity-reduced versions of combined modality treatment.