Surgery for primary CNS lymphoma? Challenging a paradigm

The standard of care for primary central nervous system lymphoma (PCNSL) is systemic chemotherapy with or without whole brain radiotherapy or intrathecal chemotherapy. In contrast to treatment for other brain tumors, efforts at resection are discouraged. This is a secondary analysis of the German PCNSL Study Group–1 trial, a large randomized phase III study comprising 526 patients with PCNSL. Progression-free survival (hazard ratio [HR]: 1.39; 95% confidence interval [CI]: 1.10–1.74; P = .005) and overall survival (HR: 1.33; 95% CI: 1.04–1.70; P = .024) were significantly shorter in biopsied patients compared with patients with subtotal or gross total resections. This difference in outcome was not due to age or Karnofsky performance status (KPS). When controlled for the number of lesions, the HR of biopsy versus subtotal or gross total resection remained unchanged for progression-free survival (HR = 1.37; P = .009) but was smaller for overall survival (HR = 1.27; P = .085). This analysis of the largest PCNSL trial ever performed challenges the traditional view that the extent of resection has no prognostic impact on this disease. Therefore, we propose to reconsider the statement that efforts at resection should be discouraged, at least if resection seems safe, as is often the case in treatment of single PCNSL lesions.     

Consensus recommendations for MRI and PET imaging of primary central nervous system lymphoma: guideline statement from the International Primary CNS Lymphoma Collaborative Group (IPCG)

Advanced molecular and pathophysiologic characterization of primary central nervous system lymphoma (PCNSL) has revealed insights into promising targeted therapeutic approaches. Medical imaging plays a fundamental role in PCNSL diagnosis, staging, and response assessment. Institutional imaging variation and inconsistent clinical trial reporting diminishes the reliability and reproducibility of clinical response assessment. In this context, we aimed to: (1) critically review the use of advanced positron emission tomography (PET) and magnetic resonance imaging (MRI) in the setting of PCNSL; (2) provide results from an international survey of clinical sites describing the current practices for routine and advanced imaging, and (3) provide biologically based recommendations from the International PCNSL Collaborative Group (IPCG) on adaptation of standardized imaging practices. The IPCG provides PET and MRI consensus recommendations built upon previous recommendations for standardized brain tumor imaging protocols (BTIP) in primary and metastatic disease. A biologically integrated approach is provided to addresses the unique challenges associated with the imaging assessment of PCNSL. Detailed imaging parameters facilitate the adoption of these recommendations by researchers and clinicians. To enhance clinical feasibility, we have developed both “ideal” and “minimum standard” protocols at 3T and 1.5T MR systems that will facilitate widespread adoption.     

Primary central nervous system lymphoma: biological aspects and controversies in management

INTRODUCTION: This review was produced from the workshop on primary central nervous system lymphoma (PCNSL) at the European Cancer Conference (ECCO 13) in Paris in 2005. It covers the presentation and biological features of the disease (Professor Khe Hoang-Xuan). The role of chemotherapy, including the management of intraocular lymphoma and the use of high dose chemotherapy followed by autologous stem cell transplantation for PCNSL, is discussed (Dr. Andres Ferreri) as well as controversies in the use of whole brain radiotherapy (WBRT) after chemotherapy (Dr. Michele Reni). The topics covered with discussants at the workshop are also summarised. CONCLUSION: The imaging of the brain and the histopathology including detailed immunohistochemistry is of vital importance in making an accurate diagnosis of the disease and understanding the extent of spread of the disease in the CNS. The importance of high dose methotrexate (HDMTX; dose > or = 1g/m(2)), as the most active drug in the treatment of PCNSL, is stressed. The authors recommend that HDMTX alone or in combination with other active chemotherapy agents should be used to treat PCNSL followed by whole brain radiotherapy (WBRT) unless contraindicated because of the advanced age of the patient and existing cognitive impairment. Only published protocols should be used unless the patient is to be offered a trial that has either national or international support. Baseline neuropsychological tests should be carried out before treatment and repeated during and after treatment. The risks of cognitive impairment associated with the disease, with methotrexate - containing chemotherapy and with whole brain radiotherapy should be explained to patients and relatives when obtaining informed consent. Long-term survival, with current treatment regimes, is possible with PCNSL but this appears limited to patients less than 60 years of age at presentation (mostly patients less than 50 years of age).     

Chemotherapy in newly diagnosed primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) accounts for only 3% of brain tumors. It can involve the brain parenchyma, leptomeninges, eyes and the spinal cord. Unlike systemic lymphoma, durable remissions remain uncommon. Although phase III trials in this rare disease are difficult to perform, many phase II trials have attempted to define standards of care. Treatment modalities for patients with newly diagnosed PCNSL include radiation and/or chemotherapy. While the role of radiation therapy for initial management of PCNSL is controversial, clinical trials will attempt to improve the therapeutic index of this modality. Routes of chemotherapy administration include intravenous, intraocular, intraventricular or intra-arterial. Multiple trials have outlined different methotrexate-based chemotherapy regimens and have used local techniques to improve drug delivery. A major challenge in the management of patients with PCNSL remains the delivery of aggressive treatment with preservation of neurocognitive function. Because PCNSL is rare, it is important to perform multicenter clinical trials and to incorporate detailed measurements of long-term toxicities. In this review we focus on different chemotherapeutic approaches for immunocompetent patients with newly diagnosed PCNSL and discuss the role of local drug delivery in addition to systemic therapy. We also address the neurocognitive toxicity of treatment.     

Changing incidence and survival in patients with aids-related non-Hodgkin's lymphomas in the era of highly active antiretroviral therapy (HAART)

To determine role of highly active antiretroviral therapy (HAART) and additional factors in incidence and outcome of patients with AIDS-related non-Hodgkin's lymphomas (NHL) we retrospectively analyzed 257 cases of AIDS-related NHL (24 low-grade, 168 high-grade B-cell, 6 high-grade T-cell, and 59 primary CNS lymphomas (PCNSL) among 2004 patients with HIV-infection treated at the University Hospital of Frankfurt, Germany from January 1983 to May 1999. Data were evaluated by univariate and multivariate analyses, using overall survival as end point. Patients received CHOP-like therapy as standard treatment. Until May 1999 incidence of all diagnosed cases of NHL was decreasing (1991-94: 14.2% versus 1995-5/99: 12.8%). Mainly, the incidence of low-grade NHL and PCNSL clearly decreased whereas the incidence of high-grade B-cell NHL increased compared to all diagnosed cases of NHL (1983-86: 53.3% versus 1995-5/99: 78.6%). One-year survival probability of all screened patients with AIDS related NHL was 54%, while 5-year survival rate remained 5%. We found age <25 years, development of NHL in the years before 1990, IVDU, CD4 counts <150/microl, PCNSL as well as NHL as the AIDS index disease, to be highly significant independent predictors of poor survival, including increased hazard ratios. In the era of HAART incidence of NHL is decreasing, mainly the incidence of low-grade NHL and PCNSL. Overall survival of patients has been prolonged with HAART. This development is mainly due to improvement of antiretroviral therapy, rather than to any fundamental changes in the chemotherapeutic treatment of NHL. Therefore, new treatment approaches for AIDS-related NHL should focus on more efficient antiretroviral therapy in association with combination chemotherapy.     

Primary central nervous system lymphoma: a role for adjuvant chemotherapy

Summary Sixteen immunocompetent patients, 10 of whom were previously reported, with primary non-Hodgkins lymphoma of the central nervous system (PCNSL) were treated and followed longitudinally by the Neurooncology Service at the University of California, San Francisco (UCSF) and the University of California, San Diego (UCSD). After undergoing surgery (biopsy or resection), these patients received radiation therapy (RT) with hydroxyurea (HU) followed by adjuvant chemotherapy with the combination of procarbazine, CCNU, and vincristine (PCV) as previously reported. All patients ultimately died of progressive recurrent PCNSL. Toxicity using the HU + RT followed by PCV schedule was tolerable. Median and quartile survival data (41 and 65 months, respectively) suggest efficacy for this chemotherapy schedule and further emphasizes a role for adjuvant chemotherapy in the primary treatment of PCNSL.     

Expression of signal transducer and activator of transcription 3 (STAT3) in primary central nervous system diffuse large B-cell lymphoma: a retrospective analysis of 17 cases

Most primary central nervous system lymphomas (PCNSL) occurring in immunocompetent patients are diffuse large B-cell lymphomas (DLBCL), characterized by poor prognosis. An activated B-cell (ABC) origin of PCNSL has been postulated based on bcl-6 and MUM-1 expression by majority of these tumors. ABC DLBCL has been functionally subdivided using gene expression profiling and immunohistochemical analysis into STAT3-high and STAT-3 low subsets. A potentially crucial difference between STAT3-high and STAT3-low ABC DLBCL is in the expression of bcl-2 family members. STAT3-high cases are generally bcl-2 low and STAT3-low cases show higher expression of bcl-2. Further mechanisms such as activation of nuclear factor-kappa B (NF-κB) activation seem to be responsible for upregulation of bcl-2 in ABC subtype of DLBCL with an adverse outcome. As deregulation of STAT-3 pathway is known to play a critical role in ABC DLBCL and majority of the PCNSL are of the ABC subtype we studied the immunohistochemical expression of STAT-3 proteins in PCNSL along with other traditional markers (CD10, bcl-6, MUM-1 and bcl-2) in 17 cases of PCNSL occurring in immunocompetent patients. Despite lack of STAT3 expression in all our cases, majority (70%) of the patients with bcl-2 positive PCNSL had an adverse outcome similar to that reported in systemic lymphomas of ABC subtype. Based on our observations we propose that PCNSL represents a distinct subset of ABC diffuse large B-cell lymphomas with low STAT3 expression and perhaps mechanisms other than interaction of STAT-3 and NF-κB pathways may play a role in upregulation of bcl-2 in PCNSL. To the best of our knowledge expression of STAT-3 protein in PCNSL which represents a distinct anatomical subset of ABC DLBCL with a dismal prognosis has not been studied before.     

First report on a prospective trial with yttrium-90–labeled ibritumomab tiuxetan (Zevalin) in primary CNS lymphoma

Most patients with primary CNS lymphoma (PCNSL) relapse after primary therapy. Standard salvage treatment has not yet been established in PCNSL. Anti-CD20 immunotherapy has expanded treatment options in systemic B-cell lymphoma; however, its use is limited by reconstitution of the blood–brain barrier after tumor shrinkage. The aim of this phase II trial was to evaluate the therapeutic efficacy, toxicity, and biodistribution of yttrium-90 (⁹⁰Y) ibritumomab tiuxetan in PCNSL. Ten patients with relapsed PCNSL were included in a phase II trial and treated with the ⁹⁰Y-labeled anti-CD20 antibody ibritumomab tiuxetan. Nine patients actually received the planned radioimmunotherapy. In six patients, biodistribution of the antibody was measured by indium-111 (¹¹¹In) ibritumomab tiuxetan whole-body scans and single-photon-emission CT (SPECT) of the brain. All patients were evaluated for toxicity and response at least 4 weeks after therapy. Four patients responded: one patient had a complete response lasting 30+ months, and three patients had short-lived responses of ≤4 weeks. Five patients progressed, and one patient did not receive treatment due to an infection prior to ⁹⁰Y-antibody administration. Target accumulation of the antibody was demonstrated in four of the six patients examined by SPECT imaging with ¹¹¹In ibritumomab tiuxetan. All patients experienced grade 3/4 hematotoxicity but no acute neurotoxicity. Penetration of a therapeutic antibody into PCNSL and significant clinical activity was shown. Because of limited response duration and considerable hematotoxicity, future investigations should focus on a multimodal approach with additional chemotherapy and preferably autologous stem cell support.     

Primäre ZNS-Lymphome

Primary CNS lymphomas (PCNSL) are rare brain tumors comprising only 3% of all primary intracranial neoplasms. The median age at diagnosis ranges between 60 and 65 years. PCNSLs often cause a rapidly progressing psychosyndrome. Magnetic resonance imaging (MRI) reveals multiple or single lesions with homogenous contrast enhancement often in the vicinity of the ventricles. The diagnostic method of choice is stereotactic biopsy. In more than 90% of cases a highly malignant B-cell non-Hodgkin’s lymphoma of the diffuse large-cell type is diagnosed. Patients should be included in clinical studies in order to optimize therapy. Patients younger than 60 years old are expected to be treated curatively and should receive polychemotherapy including systemic high-dose methotrexate (MTX). The role of high-dose chemotherapy with autologous stem cell transplantation as primary treatment has not finally been defined. For patients older than 60 years a curative treatment strategy is not established and in addition, toxicity plays a major role. A MTX-based chemotherapy, e.g. in combination with ifosfamide or temozolomide can be administered. Radiotherapy alone as primary treatment is not recommended. Combination radiotherapy with MTX-based chemotherapy is also not established, demonstrating a high rate of neurotoxicity at late follow-up. In the case of recurrence there are a number of possible treatment options depending on the primary therapy. In Germany, several study groups are organized and the aim of these consortia is optimization of PCNSL therapy.     

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.     

The utility of body FDG PET in staging primary central nervous system lymphoma

(18)F-Fluorodeoxyglucose (FDG) PET has become an important tool in the management of non-Hodgkin's lymphoma (NHL), but its role in the evaluation of primary CNS lymphoma (PCNSL) has not been established. We investigated the ability of body FDG PET to detect systemic disease in the staging and restaging of PCNSL. The records of 166 PCNSL patients seen at Memorial Sloan-Kettering Cancer Center were examined. Forty-nine patients who underwent body FDG PET for staging of PCNSL were identified. Clinical data were reviewed to determine FDG PET results and their influence on therapy. Body FDG PET disclosed a systemic site of malignancy in 15% of patients. NHL was found in 11% of all patients, 7% of patients at diagnosis, and 27% of patients at CNS relapse. Four percent had a second systemic neoplasm. Workup with conventional staging did not reveal systemic disease, and in 8% of patients, body FDG PET was the only abnormal diagnostic exam suggestive of lymphoma. FDG PET findings altered patient treatment and resulted in additional chemotherapy, surgery, or radiotherapy. Our findings suggest that FDG PET may be more sensitive than conventional body staging and may disclose higher rates of concomitant systemic disease at PCNSL diagnosis. Body FDG PET may be an important noninvasive adjunct to conventional PCNSL staging, and its utility should be evaluated prospectively.     

Case report of a patient with primary central nervous system lymphoma treated with radioimmunotherapy

Primary central nervous system lymphoma (PCNSL) is a rare form of non-Hodgkin lymphoma arising within and confined to the central nervous system and, unlike other primary brain tumors, is very responsive to treatment. Aggressive management can lead to prolonged remissions or cures. However, the prognosis at relapse is generally poor with limited therapeutic options; clearly, new strategies are needed for these patients. Radioimmunotherapy has a growing role in the management of systemic non-Hodgkin lymphoma but has not been evaluated in PCNSL. We report here the first patient with PCNSL treated with radioimmunotherapy.     

Pemetrexed in the treatment of relapsed/refractory primary central nervous system lymphoma

BACKGROUND:

Despite initial treatment with high‐dose methotrexate‐based regimens, many patients with primary central nervous system lymphoma (PCNSL) relapse and die from their disease. No standard of care exists at progression or relapse, but chemotherapy and in some cases radiation are usually used. Pemetrexed is a multitargeted antifolate, similar to methotrexate, but with a broader spectrum of activity. Because methotrexate is an integral part of PCSNL treatment, the authors assessed the antitumor activity and safety of pemetrexed in recurrent PCNSL.

METHODS:

Patients with relapsed/refractory PCNSL were enrolled in this trial. Treatment consisted of pemetrexed 900 mg/m² given every 3 weeks with low‐dose dexamethasone, folate, and B12 supplementation. Each cycle was 6 weeks, and follow‐up imaging was done before each new cycle. Treatment was continued until complete remission, progression, or toxicity.

RESULTS:

Eleven patients were treated, with a median age of 69.8 years and Karnofsky performance status of 70%; 10 of 11 patients had failed prior high‐dose methotrexate. The median number of pemetrexed cycles given was 5, with an associated overall response rate of 55% and disease control rate of 91%. The 6‐month progression‐free survival (PFS) was 45%, median PFS was 5.7 months, and median overall survival was 10.1 months. Toxicities were primarily hematologic and infectious.

CONCLUSIONS:

Pemetrexed has single‐agent activity in relapsed/refractory PCNSL. Toxicities were seen likely because of the higher than standard dose used. Further investigation of this agent or other multitargeted antifolates in PCNSL is warranted to determine optimal dose and efficacy in a more homogeneous population. Cancer 2012. © 2011 American Cancer Society.     

Salvage chemotherapy with temozolomide in primary CNS lymphomas: preliminary results of a phase II trial

Temozolomide is a well-tolerated alkylating agent, that is able to permeate the blood-brain barrier (BBB), and has additive cytotoxicity when given with radiotherapy (RT). A phase II trial assessing temozolomide 150 mg/m(2)/day, for 5 days every 28 days in primary central nervous system (CNS) lymphoma (PCNSL) patients with negative human immunodeficiency virus (HIV) serology, Eastern Cooperative Oncology Group (ECOG) performance status (PS)<4, previously treated with high-dose methotrexate-containing (HD-MTX) chemotherapy and/or RT was started. Twenty-three patients were enrolled. Median age was 60 years. Five complete remissions (median duration 6+ months; range 2-36 months), one partial response, four stable disease (median duration 7.2 months, range 2-16.5 months), and 13 progressions were observed. No major toxicities were observed, apart grade 3 vomiting in a single cycle. Main grade 1-2 toxicities were: 15% nausea, 6% vomiting, 9% fatigue and 9% neurological symptoms. This is the first prospective trial assessing single-agent activity in PCNSL at failure. Although some patients had a poor PS and had been heavily pre-treated, temozolomide yielded 26% objective responses and was well tolerated without any major toxicity.     

Prevention of recurrence and prolonged survival in primary central nervous system lymphoma (PCNSL) patients treated with adjuvant high-dose methylprednisolone

Five patients at risk for primary central nervous system lymphoma (PCNSL) recurrence were treated with high-dose methylprednisolone (HDMP) to prevent 'trafficking' of malignant lymphocytes into the central nervous system (CNS). HDMP was chosen because of its ability to stabilize the 'blood brain barrier (BBB)'. Three men with newly diagnosed PCNSL, ages 62, 76 and 78y, whose survival was projected to be 6.6 months, began treatment after achieving complete response (CR) to initial radiation therapy alone and survived 27, 37 and 59 months after treatment. In none was death from recurrent disease in CNS but one patient did die of systemic non-Hodgkin's lymphoma (NHL) five years after PCNSL diagnosis. A 20 y old man was treated with HDMP after successful combined modality therapy and is alive 75+ months after initial diagnosis without evidence of disease recurrence. A 34 y old man relapsed after combined modality initial treatment and failed to respond to HDMP when treatment was begun after unsuccessful salvage therapy; he died of disease 12 months after initial diagnosis. There were no treatment complications. The promising results in this pilot study from the basis for a North Central Cancer Treatment Group (NCCTG) 96-73-51, a Phase 2 clinical trial of brain radiotherapy and HDMP for PCNSL patients 70y of age and older, a group of patients at high risk for toxicity from intensive combined modality therapy.     

Incidence and radiographic findings of primary central nervous system lymphoma in immunocompetent patients in southern Thailand

AIMS AND BACKGROUND: In the last two decades there have been conflicting reports concerning a rising incidence of primary central nervous system lymphoma (PCNSL) in immunocompetent patients. This study is being conducted to review the incidence and radiographic findings of PCNSL in a large tertiary care institution in southern Thailand. PATIENTS: A review was carried out in Songklanagarind University Hospital of the clinical records, CT and MRI images of immunocompetent patients who had histologically proven PCNSL diagnosed between January 1993 and December 2004. RESULTS: A total of 25 PCNSL patients were diagnosed over a 12-year period. The incidence trend was rising but not to a statistically significant extent. The median age at diagnosis was 57.4 years. Based on the Working Formulation classification, diffuse large cell was the most common subtype. All of the 20 patients with available immunohistochemical results had B-cell lymphomas. The radiographic findings in our series show that the majority of patients had a single lesion (60%) at a supratentorial location (50%). Most of the lesions were well circumscribed. Based on the density of the lesions before administration of a contrast medium, 56% of the lesions on CT images appeared hyperdense. On T1-weighted MRI images, the lesions of our patients were most frequently hypointense (67%) while the T2-weighted images were more commonly hyperintense (60%) and contrast enhancement was found in all lesions. There were 21 patients who received whole brain radiotherapy with doses ranging between 4.2 and 6.0 Gy. The median survival time was 14.4 months. CONCLUSIONS: This study indicates that there has been no significant increase in PCNSL cases over the last 12 years. The recognition of characteristic imaging features of PCNSL may facilitate a stereotactic procedure before steroid administration. In addition, we provide evidence that radiotherapy alone is insufficient in PCNSL.     

原发性中枢神经系统淋巴瘤临床病理及免疫组化研究

[目的]探讨原发性中枢神经系统恶性淋巴瘤(PCNSI。)的病理学特点。[方法]收集10例PCNSL病人的临床资料，并进行病理形态及免疫组化分析。[结果]PCNSL病理形态及免疫组化结果提示均为B细胞性淋巴瘤，其中8例为弥漫性大B细胞淋巴瘤，2例为小淋巴细胞性淋巴瘤。[结论]PCNSL是少见的颅内肿瘤，绝大部分为B细胞性，其亲血管性常形成血管袖套状结构。免疫组化在诊断与鉴别诊断中起着重要作用。     

Surgical removal of primary central nervous system lymphomas (PCNSL) presenting as space occupying lesions: a series of 33 cases.

AIMS: In this study we present a series of 33 patients with primary CNS lymphomas (PCNSL), many presenting with acute signs of increased intracranial pressure due to large space occupying lesions. METHODS: A series of 32 PCNSL patients for a total of 33 tumours treated from 1986 to 2000 in the Neurosurgical Department were reviewed. RESULTS: Radiotherapy and chemotherapy improved survival. No benefit could be demonstrated for the role of surgery. CONCLUSIONS: Our data confirm previous reports about the role of radiation and chemotherapy in the treatment of PCNSL's. Surgery might have a role in a selected subset of patients presenting with large single space occupying lesions and deteriorating neurological status.     

MicroRNAs in cerebrospinal fluid as biomarker for disease course monitoring in primary central nervous system lymphoma

Diagnosis of primary lymphomas of the central nervous system (PCNSL) largely depends on histopathology of tumor biopsies. Recently, we identified miRNAs detected in the CSF of PCNSL patients as novel non-invasive biomarkers for this disease. In combined analyses of miR-21, miR-19b, and miR-92 CSF levels, it was possible to differentiate PCNSL from other neurological disorders. In the current study, we first confirmed our previous findings in an enlarged PCNSL cohort (n?=?39; sensitivity 97.4?%). Also, we sought to establish the potential role of CSF miRNAs as biomarkers for disease course monitoring. In sequential miRNA measurements in CSF derived from nine patients with different disease courses, an intriguing correlation of miRNA levels and PCNSL status during treatment and/or disease follow-up was demonstrated. Finally, we demonstrated that miRNA levels in serum of PCNSL patients (n?=?14) were not elevated as compared to controls. In summary, this study provides the first evidence that CSF miRNAs have the potential as biomarkers for treatment monitoring and disease follow-up of patients with PCNSL.     

Primary central nervous system lymphoma: a single-centre experience of 55 unselected cases

AimsCurrent treatment for primary central nervous system lymphoma (PCNSL) involves high-dose methotrexate (HDMTX) with or without radiotherapy. Many published studies describing this approach include a highly selected group of patients. We report a single-centre experience of unselected cases of PCNSL.Materials and methodsWe retrospectively reviewed the case notes of 55 consecutive patients diagnosed with biopsy-proven PCNSL between 1995 and 2003 at Addenbrooke's Hospital Cambridge, UK. We describe the treatment and outcome, including survival, treatment-related toxicity and long-term functional disability.ResultsAt diagnosis, 45% of patients were considered unfit to receive treatment with HDMTX, owing to poor performance status or comorbidity. These patients had a median survival of 46 days and may not have been included in other published studies. The remaining patients were treated with a chemotherapy regimen, which included HDMTX. Patients who received at least one cycle of a chemotherapy containing HDMTX had a median survival of 31 months. Forty per cent did not complete planned chemotherapy owing to toxicity, disease progression or death. The median survival of patients treated with HDMTX aged 60 years compared with patients aged under 60 years was 26 months vs 41 months (P = 0.07), respectively. Younger patients treated with HDMTX, who achieved complete remission with chemotherapy, had a median survival of 56 months. We identified a high incidence of functional disability among survivors, resulting from a combination of the tumour itself, the neurosurgical procedure required for diagnosis and the late neurotoxicity of combined chemoradiotherapy.ConclusionThe treatment of PCNSL is associated with significant early and late toxicity. Further attempts to improve treatment should address mechanisms to reduce this toxicity. In particular, the benefit of radiotherapy in patients who achieve complete remission with HDMTX will remain uncertain until it is addressed in a multicentre, randomised trial.