Primary CNS lymphoma in patients younger than 60: can whole-brain radiotherapy be deferred?

Radiotherapy for newly diagnosed primary central nervous system lymphoma: role and perspective

Whole brain radiotherapy (WBRT) has long been a key treatment of newly diagnosed primary central nervous system lymphoma (PCNSL). In the 1990s, the addition of high dose Methotrexate-based induction chemotherapy (HD MTX-based CT) has enabled a drastic improvement in PCNSL patients outcome. However, combined treatment has led to radiation-induced delayed neurotoxicity, especially in older patients. Alternative treatment strategies have been assessed to improve the efficacy and neurotoxicity ratio. Nowadays, in the elderly patients WBRT is widely omitted or deferred, and in younger patients WBRT is challenged by high dose chemotherapy with autologous stem cell transplant (HCT-ASCT) for consolidation treatment after HD MTX-based CT. In this setting, this review is addressed to clinicians with the aim to summarize the role of WBRT in the treatment of newly diagnosed PCNSL and its perspectives.

European Association of Neuro-Oncology (EANO) guidelines for treatment of primary central nervous system lymphoma (PCNSL)

The management of primary central nervous system (PCNSL) is one of the most controversial topics in neuro-oncology because of the complexity of the disease and the limited number of controlled studies available. In 2021, given recent advances and the publication of practice-changing randomized trials, the European Association of Neuro-Oncology (EANO) created a multidisciplinary task force to update the previously published evidence-based guidelines for immunocompetent adult patients with PCNSL and added a section on immunosuppressed patients. The guideline provides consensus considerations and recommendations for the treatment of PCNSL, including intraocular manifestations and specific management of the elderly. The main changes from the previous guideline include strengthened evidence for the consolidation with ASCT in first-line treatment, prospectively assessed chemotherapy combinations for both young and elderly patients, clarification of the role of rituximab even though the data remain inconclusive, of the role of new agents, and the incorporation of immunosuppressed patients and primary ocular lymphoma. The guideline should aid the clinicians in everyday practice and decision making and serve as a basis for future research in the field.

Reduced-dose WBRT as consolidation treatment for patients with primary CNS lymphoma: a LOC-network study

After consolidation rdWBRT in a subset of patients, most of the patients exhibited sustained or improved cognitive function.

rdWBRT should be considered a strong consolidation treatment for PCNSL in patients aged <60 years showing CR after induction chemotherapy.

The optimal consolidation strategy for primary central nervous system lymphoma (PCNSL) remains controversial. Preventing radio-induced neurotoxicity of consolidation treatment through reduced-dose whole-brain radiotherapy (rdWBRT) at a dose of 23.4 Gy is an interesting alternative to conventional WBRT in patients aged <60 years. From the LOC Network (Network for Oculo-cerebral Lymphomas) database, we retrospectively selected patients with PCNSL aged <60 years who showed complete (CR) or unconfirmed CR after high-dose methotrexate–based chemotherapy and had received consolidation rdWBRT as the first-line treatment. If available, prospective neuropsychological follow-ups were reported. Twenty-nine patients diagnosed between 2013 and 2018 met the study selection criteria. Nine (31%) patients experienced relapse during the follow-up, with a median time from radiotherapy to recurrence of 8.7 months (interquartile range, 4-11.5). Five of those patients received salvage treatment and consolidation with intensive chemotherapy and autologous stem cell transplantation. Progression-free survival rates were 89% (95% confidence interval [CI] 79%-100%), 72% (95% CI, 56%-88%), and 69% (95% CI, 52%-85%) at 1, 2, and 5 years, respectively. Overall survival rates were 100%, 89% (95% CI, 79%-100%), and 86% (95% CI, 74%-99%) at 1, 2, and 5 years, respectively, and were consistent with those observed for standard-dose WBRT (sdWBRT). No prognostic factor was identified. The results of the 36-month neuropsychological follow-up for a subset of patients appeared reassuring, with most patients exhibiting maintenance of or improvements in their baseline conditions. Our results, combined with phase 2 study results, support the use of rdWBRT instead of sdWBRT as a consolidation treatment in <60-year-old patients showing CR after induction treatment.

Chimeric antigen receptor T-cell therapy following autologous transplantation for secondary central nervous system lymphoma: A case report

RATIONALE

Chimeric antigen receptor (CAR) T-cell therapy is effective in treating relapsed and refractory B-cell non-Hodgkin lymphoma. However, because of the mortality risk associated with immune effector cell-associated neurotoxicity syndrome and pseudoprogression, patients with central nervous system (CNS) involvement are less likely to receive CAR T-cell therapy.

PATIENTS CONCERNS

We report a case of a 61-year-old, male patient with intravascular large B-cell lymphoma who suffered a CNS relapse after standard chemotherapy.

DIAGNOSIS

A diagnosis of intravascular large B-cell lymphoma with CNS involvement was made.

INTERVENTIONS

We treated the patient using CAR T-cell therapy following a conditioning regimen consisting of thiotepa and busulfan and autologous stem cell transplantation. Although he experienced grade 1 cytokine release syndrome, no other serious adverse events, such as immune effector cell-associated neurotoxicity syndrome or pseudoprogression, were observed.

OUTCOMES

The patient achieved complete remission after the CAR T-cell infusion.

LESSONS

CAR T-cell therapy following autologous stem cell transplantation is a viable option for relapsed/refractory lymphoma with CNS infiltration. Further clinical studies are warranted to verify its safety and efficacy.

Intradural primary marginal zone lymphoma of the cervical spine 2 years following a posterior cervical instrumented fusion

Primary low grade central nervous system lymphoma is a rare entity, with the majority being intracranial marginal zone B-cell lymphoma. Primary spinal lymphoma is unusual, and commonly presents as an epidural lesion with diffuse large B-cell histology, as described in prior literature. We present a case of a 56 year-old woman diagnosed with a primary intradural spinal lymphoma two years after a posterior cervical fusion at the same level. She was treated successfully with surgical resection and postoperative radiotherapy. To our knowledge, this is the first case in the literature describing an intradural primary marginal zone B-cell lymphoma of the spine.

Management of Primary Central Nervous System Lymphoma Using Intra-Arterial Chemotherapy With Osmotic Blood-Brain Barrier Disruption: Retrospective Analysis of the Sherbrooke Cohort

Background

Primary central nervous system lymphomas (PCNSL) are rare and aggressive CNS tumors. Current management involves high-dose methotrexate (HD-MTX) typically administered intravenously (IV), despite the existence of the blood-brain barrier (BBB), which significantly decreases its bioavailability. Cerebral intra-arterial chemotherapy (CIAC) coupled with osmotic BBB disruption (OBBBD) can theoretically circumvent this issue.

Methods

We performed a retrospective analysis of patients with newly diagnosed PCNSL treated with HD-MTX-based CIAC+OBBBD at our center between November 1999 and May 2018. OBBBD was achieved using a 25% mannitol intra-arterial infusion. Patients were followed clinically and radiologically every month until death or remission. Demographics, clinical and outcome data were collected from the medical record. All imaging studies were reviewed for evidence of complication and outcome assessment. Kaplan-Meier analyses were used to compute remission, progression-free survival (PFS) as well as overall survival times. Subgroup analyses were performed using the log rank test.

Results

Forty-four patients were included in the cohort. Median follow-up was 38 months. Complete response was achieved in 34 patients (79%) at a median of 7.3 months. Actuarial median survival and PFS were 45 months and 24 months, respectively. Age, ECOG and lesion location did not impact outcome. Complications included thrombocytopenia (39%), neutropenia (20%), anemia (5%), seizures (11%), stroke (2%), and others (20%).

Conclusion

CIAC using HD-MTX-based protocols with OBBBD is a safe and well-tolerated procedure for the management of PCNSL. Our data suggests better PFS and survival outcomes compared to IV protocols with less hematologic toxicity and good tolerability, especially in the elderly.

Consecutive single-institution case series of primary central nervous system lymphoma treated by R-MPV or high-dose methotrexate monotherapy

OBJECTIVE

The optimal regimen for use of high dose-methotrexate-based chemotherapy in primary central nervous system lymphoma is still under debate. We conducted a retrospective study to evaluate the treatment outcome of a combination immunochemotherapy consisting of rituximab, methotrexate, procarbazine and vincristine followed by with or without whole brain radiotherapy and consolidation cytarabine, in comparison with high dose-methotrexate monotherapy followed by full dose whole brain radiotherapy.

METHODS

Newly diagnosed primary central nervous system lymphoma patients treated with either rituximab, methotrexate, procarbazine and vincristine or high dose-methotrexate in Kyorin University Hospital were identified, and the response rates and survival were compared. Toxicities, post-treatment transition of Mini-Mental State Examination, Karnofsky performance status score, Fazekas scale and prognostic factors were analysed in the rituximab, methotrexate, procarbazine and vincristine group.

RESULTS

Ninety-five patients treated with rituximab, methotrexate, procarbazine and vincristine (n = 39) or high dose-methotrexate (n = 56) were analysed. The complete response/complete response unconfirmed rate was significantly higher in the rituximab, methotrexate, procarbazine and vincristine group (74.4 vs. 15.4%, P < 0.001). Accordingly, both median progression-free survival and overall survival were significantly longer in the rituximab, methotrexate, procarbazine and vincristine group (median progression-free survival: unreached vs. 14.75 months, P < 0.001) (median overall survival: unreached vs. 63.15 months, P = 0.005). Although the rate of grade 3/4 hematologic toxicities was high both during rituximab, methotrexate, procarbazine and vincristine and consolidation cytarabine, the rate of grade 3/4 infections was low, and no treatment related deaths were observed. Deterioration in Karnofsky performance status or Mini-Mental State Examination was rare, except on disease recurrence. Although whole brain radiotherapy was associated with Fazekas scale deterioration, its association with Karnofsky performance status or Mini-Mental State Examination deterioration was not significant.

CONCLUSIONS

Rituximab, methotrexate, procarbazine and vincristine was apparently promising in comparison with high dose-methotrexate monotherapy with manageable toxicity in this retrospective study, and further investigation is warranted.

Reduced-dose whole-brain radiotherapy with tumor bed boost after upfront high-dose methotrexate for primary central nervous system lymphoma

Purpose

This retrospective study compares higher-dose whole-brain radiotherapy (hdWBRT) with reduced-dose WBRT (rdWBRT) in terms of clinical efficacy and toxicity profile in patients treated for primary central nervous system lymphoma (PCNSL).

Materials and Methods

Radiotherapy followed by high-dose methotrexate (HD-MTX)-based chemotherapy was administered to immunocompetent patients with histologically confirmed PCNSL between 2000 and 2016. Response to chemotherapy was taken into account when prescribing the radiation dose to the whole brain and primary tumor bed. The whole brain dose was ≤23.4 Gy for rdWBRT (n = 20) and >23.4 Gy for hdWBRT (n = 68). Patients manifesting cognitive disturbance, memory impairment and dysarthria were considered to have neurotoxicity. A median follow-up was 3.62 years.

Results

The 3-year overall survival (OS) and progression-free survival (PFS) were 70.0% and 48.9% with rdWBRT, and 63.2% and 43.2% with hdWBRT. The 3-year OS and PFS among patients with partial response (n = 45) after chemotherapy were 77.8% and 53.3% with rdWBRT, and 58.3% and 45.8% with hdWBRT (p > 0.05). Among patients with complete response achieved during follow-up, the 3-year freedom from neurotoxicity (FFNT) rate was 94.1% with rdWBRT and 62.4% with hdWBRT. Among patients aged ≥60 years, the 3-year FFNT rate was 87.5% with rdWBRT and 39.1% with hdWBRT (p = 0.49). Neurotoxicity was not observed after rdWBRT in patients aged below 60 years.

Conclusion

rdWBRT with tumor bed boost combined with upfront HD-MTX is less neurotoxic and results in effective survival as higher-dose radiotherapy even in partial response after chemotherapy.

Whole brain radiotherapy improves survival outcomes in primary CNS lymphoma patients ineligible for systemic therapy

PURPOSE

Primary central nervous system lymphoma (PCNSL) is a very rare type of malignancy with a poor prognosis. The role of whole brain radiotherapy (WBRT) in PCNSL has been questioned due to the significant neurotoxicity and lack of convincing data for survival benefit. Even its role in a palliative setting remains to be clearly elucidated. Our study aims to investigate the benefit of WBRT in patients who are ineligible for systemic therapy.

METHODS

A single-institution retrospective study was conducted on patients diagnosed with PCNSL between 2002 and 2017. Patients were excluded if they received systemic therapy or focal radiation only. Data on patient demographics and WBRT were collected and correlated with clinical outcomes.

RESULTS

A total of 48 patients were selected for analysis, among which 31 (64.6%) patients received WBRT and 17 (35.4%) patients received supportive care only. Patient baseline characteristics were similar between the two groups. Median overall survival (OS) was 4.3 months among the entire cohort. WBRT was associated with improved median OS (8.0 months, range 1.4-62.3 months) compared with supportive care only (3.3 months, range 0.7-18.3 months) (HR 0.39, 95% CI 0.20-0.75, p = 0.005). Among patients who received WBRT, higher radiation dose to the whole brain was not associated with survival (p = 0.10), but higher radiation dose to the gross tumor was associated with improved survival (p = 0.007).

CONCLUSION

Patients with PCNSL who are ineligible for systemic therapy may still benefit from WBRT with improvement in survival, compared with the best supportive care. Dose escalation through the addition of a gross tumor boost in these patients was associated with improved overall survival. Further studies in the prospective setting are necessary to confirm the findings from the study.

Radiotherapy or Autologous Stem-Cell Transplantation for Primary CNS Lymphoma in Patients 60 Years of Age and Younger: Results of the Intergroup ANOCEF-GOELAMS Randomized Phase II PRECIS Study

PURPOSE

To determine the efficacy and toxicity of chemoimmunotherapy followed by either whole-brain radiotherapy (WBRT) or intensive chemotherapy and autologous stem-cell transplantation (ASCT) as a first-line treatment of primary CNS lymphoma (PCNSL).

PATIENTS AND METHODS

Immunocompetent patients (18 to 60 years of age) with untreated PCNSL were randomly assigned to receive WBRT or ASCT as consolidation treatment after induction chemotherapy consisting of two cycles of R-MBVP (rituximab 375 mg/m2 day (D) 1, methotrexate 3 g/m2 D1; D15, VP16 100 mg/m2 D2, BCNU 100 mg/m2 D3, prednisone 60 mg/kg/d D1-D5) followed by two cycles of R-AraC (rituximab 375 mg/m2 D1, cytarabine 3 g/m2 D1 to D2). Intensive chemotherapy consisted of thiotepa (250 mg/m2/d D9; D8; D7), busulfan (8 mg/kg D6 through D4), and cyclophosphamide (60 mg/kg/d D3; D2). WBRT delivered 40 Gy (2 Gy/fraction). The primary end point was 2-year progression-free survival. Cognitive outcome was the main secondary end point. Analysis was intention to treat in a noncomparative phase II trial.

RESULTS

Between October 2008 and February 2014, 140 patients were recruited from 23 French centers. Both WBRT and ASCT met the predetermined threshold (among the first 38 patients in each group, at least 24 patients were alive and disease free at 2 years). The 2-year progression-free survival rates were 63% (95% CI, 49% to 81%) and 87% (95% CI, 77% to 98%) in the WBRT and ASCT arms, respectively. Toxicity deaths were recorded in one and five patients after WBRT and ASCT, respectively. Cognitive impairment was observed after WBRT, whereas cognitive functions were preserved or improved after ASCT.

CONCLUSION

WBRT and ASCT are effective consolidation treatments for patients with PCNSL who are 60 years of age and younger. The efficacy end points tended to favor the ASCT arm. The specific risk of each procedure should be considered.

Primary Central Nervous System Lymphoma: Molecular Pathogenesis and Advances in Treatment

Primary central nervous system lymphoma (PCNSL) is a group of extranodal non-Hodgkin lymphoma that exhibits specific biological characteristics and clinical behavior, with an aggressive disease course and unsatisfactory patient outcomes. It is of great importance to identify aberrant genetic loci and important molecular pathways that might suggest potential targets for new therapeutics and provide prognostic information. In this review, we listed various genetic and epigenetic alterations that are involved in PCNSL pathogenesis. In the aspect of treatment, we summarized the related literatures and evaluated the efficacy of surgery, induction chemotherapy, radiotherapy, intrathecal chemotherapy, and autologous stem cell transplantation in PCNSL. We also proposed the possible new agents for recurrent and relapse PCNSL based on the result of recent clinical researches.

Management of primary central nervous system lymphoma

A rare tumor, primary central nervous system lymphoma can affect immunocompetent and immunocompromised patients. While sensitive to radiotherapy or chemotherapy crossing the blood-brain barrier, it often recurs. Modern treatment consists of high-dose methotrexate-based induction chemotherapy, often followed by consolidation with either radiotherapy or further chemotherapy. Neurotoxicity is however a concern with radiotherapy, especially for patients older than 60 years. The benefit of the addition of rituximab to chemotherapy is unclear. Targeted therapies and immunotherapy have been effective in some patients and are tested on a larger scale. Survival has improved in the last decade, but remains poor in older patients.

A prospective phase II trial of response adapted whole brain radiotherapy after high dose methotrexate based chemotherapy in patients with newly diagnosed primary central nervous system lymphoma-analysis of acute toxicity profile and early clinical outcome

BACKGROUND

The treatment of primary CNS lymphoma (PCNSL) comprises high dose methotrexate (HDMTX) based chemotherapy followed by whole brain radiotherapy (WBRT), the major drawback of which is long term neurotoxicity. We intended to assess the feasibility of response adapted WBRT in PCNSL in the Indian setting.

METHODS

We screened 32 patients and enrolled 22 eligible patients with PCNSL from 2015 to 2017 in a prospective phase II trial. The patients underwent five 2-weekly cycles of induction chemotherapy with rituximab, methotrexate, vincristine, procarbazine. Patients with complete response(CR) to induction chemotherapy were given reduced dose WBRT 23.4 Gy/13 fractions/2.5 weeks while those with partial response (PR), stable or progressive disease (SD or PD) were given standard dose WBRT 45 Gy/25 fractions/5 weeks. Thereafter two cycles of consolidation chemotherapy with cytarabine were given. The primary endpoints of the study were assessment of response rate (RR) and progression free survival (PFS). The secondary endpoints of the study were assessment of overall survival (OS), toxicity profile of treatment and serial changes in quality of life and neuropsychological parameters.

RESULTS

Out of 19 patients who completed HDMTX based chemotherapy, 10 (52.63%) patients achieved CR, 8 (42.11%) patients had PR and 1 patient had PD. After a median follow-up period of 11.25 months, the estimated median OS was 19 months. The actuarial rates of PFS and OS were respectively 94.1 and 68.2% at 1 year and 50.2 and 48.5% at 2 years. Three patients in reduced dose WBRT arm had recurrence and two of them died of progressive disease, whereas there was no recurrence or disease related death in standard dose WBRT arm. On univariate analysis of PFS, age ≤ 50 years and use of standard dose WBRT (45 Gy) led to significantly improved outcome (p value 0.03 and 0.02 respectively).

CONCLUSION

In patients with PCNSL, reduced dose WBRT after CR to HDMTX based chemotherapy may lead to suboptimal clinical outcome due to higher risk of recurrence, progression and early death. Trial Registration No CTRI/2015/10/006268.

Radiotherapy as an alternative treatment option for primary central nervous system lymphoma patients who are noncandidates for chemotherapy

The standard treatment for primary central nervous system (CNS) lymphoma is based on chemotherapy. However, there are patients who are not indicated for chemotherapy and when left untreated, the expected functional outcomes for these patients are devastating since the disease causes various neurologic symptoms. Therefore, we assessed the effects of radiotherapy as an alternative therapy in primary CNS lymphoma. Thirty-two patients were diagnosed with primary CNS lymphoma and treated with radiotherapy alone. Patients received whole brain radiotherapy (WBRT) to a median dose of 30 Gy (range, 14.4–50 Gy) and the median total radiotherapy dose was 50 Gy (range, 30–54 Gy). The status on neurologic symptoms before and after radiotherapy was inquired during the regular follow-ups. The progression-free survival (PFS) and overall survival (OS) rates for the enrolled patients were calculated. The median follow-up time was 21 months. All but one of the patients presented with neurologic symptoms. The most common symptoms were hemiparesis and headache. After radiotherapy, these symptoms were relieved in 27 patients (84.4%). The median PFS and OS rates were 15.8 and 16.3 months, respectively. Twenty patients (62.5%) experienced recurrent disease at follow up and among them, fifteen patients (46.9%) had intracranial recurrence. The median intracranial PFS was 19.3 months. Untreated primary CNS lymphoma causes neurologic deficits and the survival after only supportive care is poor. Therefore, when chemotherapy is unfeasible, an alternative treatment should be applied and radiotherapy can be a practical option.

Primary Diffuse Large B-Cell Lymphoma of Central Nervous System: Is Still Surgery an Unorthodox Treatment?

Primary central nervous system lymphoma (PCNSL) is characterized as an extra-nodal non-Hodgkin lymphoma which develops from the neuraxis. The purpose was to report a case of a patient with a supra-tentorial tumor who underwent subtotal resection of his tumor as his biopsy was not indicative of a PCNSL tumor and had uneventful recovery until his last follow-up. A 42-year-old man was admitted to our department for generalized epileptic seizures. CT and MRI examinations revealed a tumor in his right parietal-occipital lobe that was surrounded by edema and was enhancing after gadolinium administration. The patient underwent a navigation-assisted parieto-occipital craniotomy and posterior parietal transcortical approach for tumor biopsy which was not indicative of PCNSL tumor. The surgical team decided to remove the tumor on site. Histological analysis of the resected specimen showed primary diffuse large B-cell lymphoma. Combined chemotherapy and radiation therapy was applied to the patient, and at his last follow-up (16 months), he is tumor free. In our case as in several other studies during the last decade, the outcome after the surgical resection of a PCNSL tumor in combination to radiation and chemotherapy was unexpectedly good. The role of surgery probably should be reconsidered for single lesion PCNSL tumors.

Diagnosis and treatment of primary central nervous system lymphoma: A report of nine cases and literature review

Primary central nervous system lymphoma (PCNSL) is a rare, highly malignant tumor type of the nervous system and is associated with poor prognosis. To investigate the efficacy of current treatment strategies for PCNSL, the present study retrospectively analyzed the clinical and pathological features, imaging results, clinical management, and prognoses of nine patients with PCNSL. Postoperative pathological examination confirmed a diagnosis of lymphoma in all the patients and the adopted treatment regimens were as follows: Stereotactic biopsy in combination with methylprednisolone (MP) and methotrexate (MTX) and/or radiotherapy; craniotomy in combination with dexamethasone or MP and/or radiotherapy; and neuroendoscopic surgery in combination with MP and MTX. The follow-up period was 5-27 months with an average duration of 10.1 months. After the initial three months of follow-up, the clinical symptoms of all the patients were significantly improved, with the tumor disappearing in seven patients and evidently reducing in size in two patients. However, six patients exhibited tumor recurrence, three of whom eventually succumbed to the disease during the follow-up period. Currently, comprehensive treatment strategies based on a combination of stereotactic biopsy, chemotherapy and radiotherapy are recommended for the treatment of PCNSL. However, the effectiveness of these treatments remains unsatisfactory. Thus, future studies are required to investigate methods for improving the efficacy of PCNSL treatment strategies.

R-MPV followed by high-dose chemotherapy with TBC and autologous stem-cell transplant for newly diagnosed primary CNS lymphoma

High-dose methotrexate-based chemotherapy is the mainstay of treatment of primary central nervous system lymphoma (PCNSL), but relapses remain frequent. High-dose chemotherapy (HDC) with autologous stem-cell transplant (ASCT) may provide an alternative to address chemoresistance and overcome the blood-brain barrier. In this single-center phase-2 study, newly diagnosed PCNSL patients received 5 to 7 cycles of chemotherapy with rituximab, methotrexate (3.5 g/m(2)), procarbazine, and vincristine (R-MPV). Those with a complete or partial response proceeded with consolidation HDC with thiotepa, cyclophosphamide, and busulfan, followed by ASCT and no radiotherapy. Primary end point was 1-year progression-free survival (PFS), N = 32. Median age was 57, and median Karnofsky performance status 80. Following R-MPV, objective response rate was 97%, and 26 (81%) patients proceeded with HDC-ASCT. Among all patients, median PFS and overall survival (OS) were not reached (median follow-up: 45 months). Two-year PFS was 79% (95% confidence interval [CI], 58-90), with no events observed beyond 2 years. Two-year OS was 81% (95% CI, 63-91). In transplanted patients, 2-year PFS and OS were 81%. There were 3 treatment-related deaths. Prospective neuropsychological evaluations suggested relatively stable cognitive functions posttransplant. In conclusion, this treatment was associated with excellent disease control and survival, an acceptable toxicity profile, and no evidence of neurotoxicity thus far. This trial was registered at www.clinicaltrials.gov as NCT00596154.

Primary central nervous system lymphoma: current state of anti-CD20 therapy and appraisal of reported response criteria

Primary central nervous system lymphoma (PCNSL) is an aggressive non-Hodgkin's lymphoma which is confined to the central nervous system and may also affect intraocular structures. Despite high initial rates of response to methotrexate-based chemotherapy, more than 50% of patients will experience relapse and about 10% have disease that is refractory to chemotherapy. Outcome in patients who fail treatment is very poor, and therefore new therapeutic approaches that may increase the rate of complete response and the proportion of durable remission are sought. Based on the pivotal role that anti-CD20 therapy now plays in the treatment outcome of aggressive systemic B-cell lymphomas, a similar approach is commonly being adapted for PCNSL despite the lack of evidence for its effectiveness. This review examines the current status and level of evidence for the use of monoclonal antibodies against the CD20 surface antigen, which is present on normal and malignant B-cells in PCNSL. The review covers both systemic and local (intracerebrospinal fluid or intravitreal) administration of CD20 monoclonal antibodies in PCNSL. In addition, it scrutinizes the response criteria commonly reported for evaluation of treatment outcome. The importance of differentiating unconfirmed complete response from partial response is outlined and the lack of consensus on response criteria for atypical imaging presentations of PCNSL is delineated.

Successful change of treatment strategy in elderly patients with primary central nervous system lymphoma by de-escalating induction and introducing temozolomide maintenance: results from a phase II study by the Nordic Lymphoma Group

The Nordic Lymphoma Group has conducted a phase ll trial in newly diagnosed primary central nervous system lymphoma patients applying an age-adjusted multi-agent immunochemotherapy regimen, which in elderly patients included temozolomide maintenance treatment. Patients aged 18-75 years were eligible. Thirty-nine patients aged 18-65 years and 27 patients aged 66-75 years were enrolled. The median age of the two age groups was 55 and 70 years, respectively. The overall response rate was 73.8% for the entire cohort: 69.9% in the younger and 80.8% in the elderly subgroup. With a median follow up of 22 months, the 2-year overall survival probability was 60.7% in patients aged 65 years or under and 55.6% in patients aged over 65 years (P=0.40). The estimated progression-free survival at two years was 33.1% (95%CI: 19.1%-47.9%) in patients aged under 65 years and 44.4% (95%CI: 25.6%-61.8%) in the elderly subgroup (P=0.74). Median duration of response was ten months in the younger subgroup, and not reached in the elderly patient subgroup (P=0.33). Four patients aged 64-75 years (6%) died from treatment-related complications. Survival in the two age groups was similar despite a de-escalation of induction treatment in patients aged over 65 years. Duration of response in elderly patients receiving maintenance temozolomide was longer than in the younger age subgroup. While toxicity during induction is still of concern, especially in the elderly patients, we conclude from these data that de-escalation of induction therapy in elderly primary central nervous system lymphoma patients followed by maintenance treatment seems to be a promising treatment strategy. (clinicaltrials.gov identifier:01458730).

The role of radiation therapy in the management of primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is an aggressive neoplasm with a poor prognosis. Early studies of whole brain radiation therapy (WBRT) alone revealed a robust initial response but high rates of local recurrence with long-term follow-up. The addition of high-dose methotrexate (HDMTX)-based chemotherapy improved the durability of disease control. However, delayed neurotoxicity emerged as an important complication, mainly in elderly patients. Therefore, researchers have investigated eliminating WBRT or reducing its dose. Multiple studies of chemotherapy alone have demonstrated inferior disease control. On the other hand, a phase III trial reported that WBRT may be deferred until relapse without compromising survival; however, this trial is fraught with flaws. A recent study of immunochemotherapy and dose-reduced WBRT demonstrated excellent outcomes. Currently, this regimen is being studied in a multi-institutional trial by the Radiation Therapy Oncology Group. WBRT maintains an important position in the armamentarium against PCNSL. This article aims to describe its evolving role.

Combined modality therapy versus chemotherapy alone as an induction regimen for primary central nervous system lymphoma: a cost-effectiveness analysis

BACKGROUND

In immunocompetent patients with primary central nervous system lymphoma (PCNSL), combined modality therapy (CMT) using high-dose methotrexate and radiotherapy (WBRT) has improved response rates compared with chemotherapy alone. The trade-off is delayed and potentially devastating treatment-related neurotoxicity (NT).

METHODS

A cost-effectiveness analysis using a Markov model compared CMT with chemotherapy alone in age-stratified patients with PCNSL. Baseline probabilities were derived from a systematic literature review. Direct and lost productivity costs were collected from a Canadian perspective and presented in Can$ in 2011. Outcomes were life expectancy, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio.

RESULTS

The quality-adjusted life expectancy was 1.55 QALYs for CMT and 1.53 QALYs for chemotherapy alone. In younger patients (aged <60 years), CMT yielded 2.44 QALYs, compared with 1.89 QALYs for chemotherapy alone, yielding an expected benefit with CMT of 0.55 QALYs or 6.6 quality-adjusted months. The CMT strategy dominated in younger patients, as it was Can$11 951 less expensive than chemotherapy alone. The chemotherapy-alone strategy dominated in older patients, as it was Can$11 244 less expensive than CMT, and there was no difference in QALYs between the strategies. The model was robust in sensitivity analyses of key variables tested through the plausible ranges obtained from costing sources and published literature.

CONCLUSION

The preferred induction strategy for younger patients with PCNSL appears to be CMT, which minimized cost while maximizing life expectancy and QALYs. This analysis confirms that the preferred strategy for older patients is chemotherapy alone.

Clinical outcomes of patients with newly diagnosed primary central nervous system lymphoma are comparable on treatment with high-dose methotrexate plus temozolomide and with high-dose methotrexate plus cytarabine: a single-institution experience

The role of temozolomide in untreated PCNSL patients has not yet been clearly defined. The purpose of this study was to compare the efficacy and toxicity of MT and MC chemotherapy in this population. A total of 41 consecutive patients were enrolled from March 2001 to July 2011. The ORR and CRR for MT vs. MC were 70% vs. 61.9% and 45% vs. 38.1% on ITT basis, (p = NS); 73.7% vs. 68.4% and 47.4% vs. 42.1% on PP basis, respectively (p = NS). Grade 3-4 hematological toxicities were more common in MC than in MT group (85.7% vs. 15%, p = 0.0001). One treatment-related death was observed in each group. The 5-year PFS and OS of MT (36% and 62.2%) were comparable to MC (32.6% and 46.7%), (p = NS). In summary, our preliminary results suggest that MT combination may be a simplified and effective regimen comparable to MC for newly diagnosed PCNSL.

Salvage therapy with bendamustine for methotrexate refractory recurrent primary CNS lymphoma: a retrospective case series

There is comparatively limited therapy for recurrent primary central nervous system lymphoma (PCNSL). Salvage therapies include re-challenge with high-dose methotrexate (HD-MTX), whole brain radiotherapy, temozolomide, topotecan and premetrexed. Bendamustine is a novel bifunctional alkylator with established activity in B cell systemic lymphomas but never previously evaluated in PCNSL. The objective of the current study was to assess response and toxicity of bendamustine in recurrent PCNSL following prior salvage therapy in a retrospective case series. Twelve adults [six males; six females: median age 59 years (range 43-74)] with HD-MTX refractory recurrent PCNSL were treated with bendamustine. All patients were treated at second recurrence following failure of prior salvage therapy. A cycle of bendamustine was defined as two consecutive days of treatment (100 mg/m(2)/day) administered once every 4 weeks (maximum number of cycles 6). Toxicities seen were Grade 2 (24 episodes in 10 patients) and 3 (10 episodes in 5 patients) only and included lymphopenia (8 patients), hyperglycemia (7 patients), fatigue (7 patients) and nausea (4 patients). The median number of cycles of therapy was 3.5 (range 1-6). Radiographic response was progressive disease in 5 (42%), stable disease in 1 (8%), partial response in 3 (25%) and complete response in 3 (25%). Median progression free survival (PFS) was 3.5 months (range 1-14 months) and 6-month PFS was 33 %. In this small retrospective series of select patients with recurrent PCNSL refractory to HD-MTX, bendamustine appears to have modest single agent activity with manageable toxicity. Confirmation in a larger series of similar patients is required.

Recent advances in treatment of primary central nervous system lymphoma

OPINION STATEMENT

Therapeutic options are limited in primary central nervous system lymphoma (PCNSL) with no uniform consensus on optimal management and few published, randomized trials. High-dose methotrexate in combination with other chemotherapeutic agents forms the mainstay of treatment. There hasn't been much progress beyond high-dose methotrexate in this disease, and although results from trials using high-dose chemotherapy and autologous stem-cell transplant seem promising, these need to be further validated. Moreover, the role of whole brain radiation in the upfront setting remains to be determined. However, international efforts in this direction are underway, with ongoing randomized trials in newly diagnosed PCNSL, more research on the molecular pathogenesis and biomarkers, and the use of novel agents in salvage therapy. There also is emphasis on quality of life parameters and neurocognitive status. Future treatment options should optimize high-efficacy rates while minimizing the risk of neurotoxicity.

Advantages of dose-dense methotrexate protocol for primary central nervous system lymphoma: comparison of two different protocols at a single institution

The efficacy and toxicity of high-dose methotrexate (HD-MTX)-based chemotherapy were retrospectively reviewed in patients with primary central nervous system lymphoma (PCNSL). All immunocompetent patients with histologically or radiographically diagnosed PCNSL treated between 2006 and 2012 at Niigata University Hospital were enrolled. Thirty-eight patients with a diagnosis of PCNSL were treated with one of two regimens during different time periods. During the first period, from 2006 to 2009, three 3-week cycles of MPV (MTX + procarbazine + vincristine) were administered (MPV3 group). In the second period, from 2010 to 2012, five 2-week cycles of MTX were administered (MTX5 group). High-dose cytarabine was used in both groups following HD-MTX-based chemotherapy. Whole-brain radiotherapy was used for patients who did not attain a complete response (CR) based on magnetic resonance images. In the MPV3 group, 20 out of 23 patients (87%) completed the planned treatment. The CR rate after chemotherapy was 30%, and 57% after radiation therapy. Thirteen out of 15 patients (87%) in the MTX5 group completed the planned treatment. The CR rates after chemotherapy and radiation therapy were 53% and 93%, respectively. Renal dysfunction was assessed by measuring creatinine clearance rates, which were very similar in both groups. In terms of hematologic toxicity and other adverse reactions, there was no significant difference between the two groups. In conclusion, dose-dense MTX chemotherapy improved outcome with acceptable toxicity compared with the treatment schedule for three cycles of MPV treatment.

Rituximab, methotrexate, procarbazine, and vincristine followed by consolidation reduced-dose whole-brain radiotherapy and cytarabine in newly diagnosed primary CNS lymphoma: final results and long-term outcome

PURPOSE

A multicenter phase II study was conducted to assess the efficacy of rituximab, methotrexate, procarbazine, and vincristine (R-MPV) followed by consolidation reduced-dose whole-brain radiotherapy (rdWBRT) and cytarabine in primary CNS lymphoma.

PATIENTS AND METHODS

Patients received induction chemotherapy with R-MPV (five to seven cycles); those achieving a complete response (CR) received rdWBRT (23.4 Gy), and otherwise, standard WBRT was offered (45 Gy). Consolidation cytarabine was given after the radiotherapy. The primary end point was 2-year progression-free survival (PFS) in patients receiving rdWBRT. Exploratory end points included prospective neuropsychological evaluation, analysis of magnetic resonance imaging (MRI) white matter changes using the Fazekas scale, and evaluation of the apparent diffusion coefficient (ADC) as a prognostic factor.

RESULTS

Fifty-two patients were enrolled, with median age of 60 years (range, 30 to 79 years) and median Karnofsky performance score of 70 (range, 50 to 100). Thirty-one patients (60%) achieved a CR after R-MPV and received rdWBRT. The 2-year PFS for this group was 77%; median PFS was 7.7 years. Median overall survival (OS) was not reached (median follow-up for survivors, 5.9 years); 3-year OS was 87%. The overall (N = 52) median PFS was 3.3 years, and median OS was 6.6 years. Cognitive assessment showed improvement in executive function (P < .01) and verbal memory (P < .05) after chemotherapy, and follow-up scores remained relatively stable across the various domains (n = 12). All examined MRIs (n = 28) displayed a Fazekas score of ≤ 3, and no patient developed scores of 4 to 5; differences in ADC values did not predict response (P = .15), PFS (P = .27), or OS (P = .33).

CONCLUSION

R-MPV combined with consolidation rdWBRT and cytarabine is associated with high response rates, long-term disease control, and minimal neurotoxicity.

Early response to high-dose methotrexate, vincristine, and procarbazine chemotherapy-adapted strategy for primary CNS lymphoma: no consolidation therapy for patients achieving early complete response

Optimal treatment strategies for primary central nervous system lymphoma (PCNSL) have not been established. In this study, we investigated the treatment outcomes and prognostic factors of high-dose methotrexate, vincristine, and procarbazine (MVP) chemotherapy followed by an interim response-adapted intensification strategy in immunocompetent patients with PCNSL. We evaluated the evidence of infection with Epstein-Barr virus (EBV) in both brain tumor tissue and whole blood. Forty patients were retrospectively reviewed. Ten (25 %) patients who achieved complete response (CR) in the interim analysis did not receive any additional consolidation treatment after completion of planned high-dose MVP chemotherapy. Additional radiotherapy (n = 9) or autologous stem cell transplantation (ASCT) (n = 7) was performed in patients who did not achieve CR in the interim analysis. The median age was 55 years. The overall CR rate was 62.5 % (n = 25), and the objective response rate was 75.0 %. Two-year overall survival (OS) was 59.8 %, and 2-year progression-free survival was 47.1 %. Grade 3 or 4 neutropenia and thrombocytopenia occurred in 47.5 and 32.5 % of patients, respectively. Treatment-related mortality was 15.0 % (n = 6), and four patients developed delayed neurotoxicity. There was no evidence of EBV-encoded RNA expression in brain tumor tissue. Ten (29.4 %) of 34 patients showed detectable EBV-DNA in whole blood. Poor performance status and EBV-DNA positivity in whole blood were significantly associated with inferior OS (p = 0.032, p = 0.023, respectively). We suggest that high-dose MVP chemotherapy followed by an early response-adapted intensification strategy may be effective and minimize the number of patients who receive radiotherapy or ASCT in the early course of treatment.

Diagnosis and treatment of primary CNS lymphoma

Primary CNS lymphoma (PCNSL) is a rare lymphoma that is confined to the CNS, with low tendency for systemic dissemination and a relatively aggressive course. Outcome in patients with PCNSL is often poor. Owing to its low incidence, current knowledge about optimal treatment of PCNSL is fragmentary. Chemotherapy regimens based on high-dose methotrexate are currently standard treatment for all patients with PCNSL who can tolerate such drugs. Whole-brain radiotherapy alone can lead to remission in up to 90% of patients, but often results in poor long-term disease control when given alone, and in delayed neurotoxicity when given after high-dose methotrexate. In this Review, we describe current approaches to diagnosis and treatment of PCNSL, and discuss novel therapeutic approaches that are currently in development, such as the use of rituximab and high-dose chemotherapy followed by autologous stem-cell transplantation. The possible use of intrathecal and intraventricular chemotherapy, optimal salvage treatment, and specific treatment approaches in elderly, paediatric and immunocompromised patients, are also considered.

Primary CNS lymphoma: a clinician's guide

Primary CNS lymphoma is a high malignant disease of the brain which can lead rapidly to death if diagnosis and/or the start of treatment is delayed. The age at time of diagnosis is a strong factor influencing prognosis so that in younger patients <65 years of age long-term survival may be achieved in a substantial percentage of patients, while in elderly patients long-term survival is seen much more rarely. First-line therapy consists of high-dose methotrexate-based (poly)chemotherapy. This review provides an overview of clinical presentation, steps to diagnosis, detailed information about current treatment concepts and specific information for particular clinical situations.

Rituximab is associated with improved survival for aggressive B cell CNS lymphoma

BACKGROUND

The optimal treatment strategy in patients with aggressive B cell central nervous system lymphoma suitable to receive intensive therapy is unknown. The benefit of incorporating rituximab in systemic therapy remains unclear. We performed a retrospective study examining the impact of rituximab in the context of concomitant therapies, including methotrexate, cytarabine, and radiotherapy, in patients treated with curative intent at 4 university teaching hospitals during 1996-2011.

METHODS

A retrospective study of CNS lymphoma cases treated at the participating institutions was performed in accordance with institutional ethical guidelines. Patients were included if they received a diagnosis of primary diffuse large B cell lymphoma of the CNS, were HIV negative, and were treated with curative intent.

RESULTS

One hundred twenty patients aged 21-81 years were identified. Rituximab recipients and nonrecipients were similar, except for rituximab recipients being more likely to have received a diagnosis after 2004. The median follow-up of surviving patients was 30 months. The 5-year overall survival was 46%. Univariate analysis revealed age ≤60 years, ECOG performance status ≤1, normal lactate dehydrogenase, diagnosis after 2004, and treatment with cytarabine and rituximab as predictive of favorable overall survival. Multivariate analysis identified age to be an independent predictor of overall survival, with a trend toward improved survival from the other variables that were significant in univariate analyses.

CONCLUSIONS

In this retrospective analysis, the addition of rituximab to high-dose methotrexate-based chemotherapy in patients with aggressive B cell CNS lymphoma was associated with improved overall survival. Further studies are underway to prospectively validate these findings.

Primary spinal marginal zone lymphoma: case report and review of the literature

BACKGROUND AND IMPORTANCE

Marginal zone lymphoma (MZL) describes a heterogeneous group of indolent B-cell lymphomas. The World Health Organization recognizes 3 types of MZLs: splenic MZL, nodal MZL, and extranodal MZL of mucosa-associated lymphoid tissue. There is no consensus on the optimal adjuvant treatment modalities for intracranial primary MZLs. To date, no case of spinal primary MZL has been reported.

CLINICAL PRESENTATION

We present the first case of spinal MZL diagnosed in a 65-year-old man with progressive paraparesis. He underwent surgical removal of the main spinal tumor mass, which extended epidurally from vertebral body T3 to T7. Surgery was followed by 10 sessions of local irradiation for a total dose of 31 Gy. On long-term follow-up in 2010, the patient was in good health without any signs of residual or recurrent disease. Twenty-seven publications reporting on 61 cases of intracranial primary MZL were identified and reviewed. In the majority of cases of marginal zone B-cell lymphoma, adjuvant radiotherapy was used, with some combining radiotherapy and chemotherapy after surgical removal of the bulk of the main tumor. Long-term follow-up in most patients showed no evidence of disease and clinical well-being years after the initial diagnosis.

CONCLUSION

Chemotherapy and/or radiation have been used in larger case series. Although there is no defined treatment guideline for this rare disease entity, our review of the literature suggests a favorable prognosis when combining surgical and adjuvant radiotherapy approaches.

Primary brain tumours in adults

Important advances have been made in the understanding and management of adult gliomas and primary CNS lymphomas--the two most common primary brain tumours. Progress in imaging has led to a better analysis of the nature and grade of these tumours. Findings from large phase 3 studies have yielded some standard treatments for gliomas, and have confirmed the prognostic value of specific molecular alterations. High-throughput methods that enable genome-wide analysis of tumours have improved the knowledge of tumour biology, which should lead to a better classification of gliomas and pave the way for so-called targeted therapy trials. Primary CNS lymphomas are a group of rare non-Hodgkin lymphomas. High-dose methotrexate-based regimens increase survival, but the standards of care and the place of whole-brain radiotherapy remain unclear, and are likely to depend on the age of the patient. The focus now is on the development of new polychemotherapy regimens to reduce or defer whole-brain radiotherapy and its delayed complications.

Prognosis after high-dose chemotherapy followed by autologous stem-cell transplantation as first-line treatment in primary CNS lymphoma--a long-term follow-up study

BACKGROUND

High-dose chemotherapy followed by autologous stem-cell transplantation (HCT-ASCT) is a promising approach in eligible patients with primary central nervous system lymphoma (PCNSL). We report long-term data of patients who were treated according to HCT-ASCT containing protocols.

PATIENTS AND METHODS

We analyzed survival and relapse rates in 43 (<67 years) immunocompetent patients with newly diagnosed PCNSL being treated according to two different high-dose methotrexate-based protocols followed by high-dose carmustine/thiotepa (BCNU/TT) plus ASCT (±whole brain irradiation). Analysis was conducted for all patients (intention-to-treat) and those patients who actually received HCT-ASCT (per-protocol).

RESULTS

Thirty-four patients achieved complete remission, of those 12 relapsed (35%), while 6 of them relapsed 5 years after diagnosis. After a median follow-up of 120 months, median overall survival (OS) was reached after 104 months. Two- and 5-year OS was 81% and 70% and 2- and 5-year event-free survival (EFS) was 81% and 67%, respectively. In per-protocol analysis (N = 34), 5-year OS and EFS was 82% and 79%, respectively. HCT-ASCT associated related mortality was not observed.

CONCLUSIONS

Sequential high-dose MTX containing chemotherapy followed by high-dose carmustine/thiotepa plus ASCT (±whole brain irradiation) is safe and leads to high survival rates in eligible patients with newly diagnosed PCNSL.

Long-term follow-up of high-dose chemotherapy with autologous stem-cell transplantation and response-adapted whole-brain radiotherapy for newly diagnosed primary CNS lymphoma: results of the multicenter Ostdeutsche Studiengruppe Hamatologie und Onkologie OSHO-53 phase II study

BACKGROUND

We previously reported the results of a phase II study for patients with newly diagnosed primary central nervous system lymphoma treated with autologous peripheral blood stem-cell transplantation (aPBSCT) and response-adapted whole-brain radiotherapy (WBRT). Now, we update the initial results.

PATIENTS AND METHODS

From 1999 to 2004, 23 patients received high-dose methotrexate. In case of at least partial remission, high-dose busulfan/thiotepa (HD-BuTT) followed by aPBSCT was carried out. Patients refractory to induction or without complete remission after HD-BuTT received WBRT. Eight patients still alive in 2011 were contacted and Mini-Mental State Examination (MMSE) and the European Organisation for Research and Treatment of Cancer quality-of-life questionnaire (QLQ)-C30 were carried out.

RESULTS

Of eight patients still alive, median follow-up is 116.9 months. Only one of nine irradiated patients is still alive with a severe neurologic deficit. In seven of eight patients treated with HD-BuTT, health condition and quality of life are excellent. MMSE and QLQ-C30 showed remarkably good results in patients who did not receive WBRT. All of them have a Karnofsky score of 90%-100%.

CONCLUSIONS

Follow-up shows an overall survival of 35%. In six of seven patients where WBRT could be avoided, no long-term neurotoxicity has been observed and all patients have an excellent quality of life.

Cognitive functions in primary CNS lymphoma after single or combined modality regimens

The standard treatment for primary CNS lymphoma (PCNSL) involves high-dose methotrexate-based chemotherapy (HD-MTX) alone or in combination with whole brain radiotherapy (WBRT). The combined modality regimen carries a substantial risk for cognitive impairment, and HD-MTX alone has been used more often recently in part to reduce neurotoxicity. In this study, we assessed cognitive functioning and quality of life in PCNSL survivors treated with WBRT + HD-MTX or HD-MTX alone. Fifty PCNSL patients in disease remission underwent a posttreatment baseline neuropsychological evaluation, and a subset of patients completed a follow-up evaluation. Quality of life and extent of white matter disease and atrophy on MRI were assessed. Comparisons according to treatment type after controlling for age and time since treatment completion showed that patients treated with HD-MTX alone had significantly higher scores on tests of selective attention and memory than patients treated with the combined modality regimen. Patients treated with WBRT + HD-MTX had impairments across most cognitive domains, and these were of sufficient severity to interfere with quality of life, as over 50% were not working due to their illness. Patients treated with HD-MTX alone did not meet criteria for cognitive impairment but scored within 1 SD below the normative sample on most tests. Patients with more extensive white matter disease had lower scores on tests of set-shifting and memory. Cognitive dysfunction was more prevalent in PCNSL survivors treated with WBRT + HD-MTX compared with patients treated with HD-MTX alone.

[Management of primary central nervous system lymphoma]

Primary CNS lymphoma is the malignant brain tumor whose prognosis has improved the most the two past decades. The majority of the patients achieve a complete remission with treatment and a substantial minority may hope to be cured. The treatment includes high-dose methotrexate polychemotherapy combined or not with whole brain radiotherapy (WBRT). Elderly patients who are exposed to a high risk of treatment induced neurotoxicity need a specific management avoiding or defering WBRT. In young patients, the main questions concerning the treatment are the role of consolidation WBRT and intensive chemotherapy with peripheral blood stem cell rescue in the initial treatment of PCNSL. As recently shown, national and international collaborative efforts make now possible randomized trials for this rare disease, which would contribute to better define the treatment strategy. New insights in PCNSL tumorigenesis would help to better understand the heterogeneity of outcome and to develop efficient targeted therapies.