Report of an international workshop to standardize baseline evaluation and response criteria for primary CNS lymphoma

Exome sequencing identifies SLIT2 variants in primary CNS lymphoma

SLIT2 constitutes a known tumour suppressor gene, which has not yet been implicated in the pathogenesis of primary central nervous system lymphoma (PCNSL). Performing exome sequencing on paired blood and tumour DNA samples from six treatment-naïve PCNSL patients, we identified novel SLIT2 variants (p.N63S, p.T590M, p.T732S) that were associated with shorter progression-free survival in our cohort and shorter overall survival in a large validation cohort of lymphoid malignancies from the cBio Cancer Genomics Portal. WNT- and NF-κB-reporter luciferase assays suggest detected alterations are loss-of-function variants. Given the possible prognostic implications, the role of SLIT2 in PCNSL pathogenesis and progression warrants further investigation.

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.

Temozolomide is effective and well tolerated in patients with primary vitreoretinal lymphoma

Baron et al report excellent responses to temozolomide in 21 patients (19 relapsed/refractory) with primary vitreoretinal lymphoma. Treatment is well tolerated, even in elderly patients.

The clinical heterogeneity of entirely nonenhancing CNS lymphoma: a case series

CNS lymphoma often presents with atypical imaging characteristics leading to delay in diagnosis and initiation of treatment. Among the most rarely reported of these is entirely nonenhancing CNS lymphoma, which is estimated at an incidence of about 1%. Here, we present three cases of nonenhancing CNS lymphoma in immune competent patients at both initial presentation and recurrence and in primary as well as secondary CNS lymphoma. Diffusion- and perfusion-weighted imaging was found helpful in diagnosis in some cases.

Primary Central Nervous System Lymphomas: A Diagnostic Overview of Key Histomorphologic, Immunophenotypic, and Genetic Features

Primary central nervous system lymphoma (PCNSL) is a rare form of extranodal non-Hodgkin lymphoma that primarily arises in the brain, spinal cord, leptomeninges, and vitreoretinal compartment of the eye. The term is sometimes used interchangeably with primary central nervous system diffuse large B-cell lymphoma (PCNS DLBCL) because DLBCL comprises a great majority (90–95%) of PCNSL. Although rare, other types of lymphomas can be seen in the central nervous system (CNS), and familiarity with these entities will help their recognition and further workup in order to establish the diagnosis. The latter is especially important in the case of PCNSL where procurement of diagnostic specimen is often challenging and yields scant tissue. In this review, we will discuss the most common types of primary lymphomas that can be seen in the CNS with emphasis on the diagnostic histomorphologic, immunophenotypic, and molecular genetic features. The differential diagnostic approach to these cases and potential pitfalls will also be discussed.

Central Nervous System Lymphomas

PURPOSE OF REVIEW

Primary central nervous system (CNS) lymphoma is a rare, aggressive extranodal non-Hodgkin lymphoma confined to the brain, eyes, CSF, or spinal cord without systemic, non-CNS involvement. This article reviews the clinical presentation, imaging characteristics, diagnostic workup, novel pathophysiologic insights, and treatment of immunocompetent patients with primary CNS lymphoma.

RECENT FINDINGS

The prognosis of primary CNS lymphoma has significantly improved over the past few decades because of the introduction of and widespread use of high-dose methotrexate, which is now the backbone of all first-line combination chemotherapy treatments. Despite this progress, durable remission is still observed in only approximately 50% of patients. Novel insights into the pathophysiology of primary CNS lymphoma have identified the B-cell receptor pathway as well as the suppressed tumor immune microenvironment and immune evasion as key mechanisms in the pathogenesis of primary CNS lymphoma. Novel, small molecules and agents targeting these aberrant pathways have been introduced into clinical trials of recurrent/refractory primary CNS lymphomas. Agents such as the Bruton tyrosine kinase (BTK) inhibitor ibrutinib or immunomodulatory drugs such as lenalidomide and pomalidomide have shown promising response rates in the relapsed setting.

SUMMARY

Diagnosis of primary CNS lymphoma requires a high level of suspicion because clinical signs and deficits can vary and depend on the involved CNS compartments. Rapid initiation of therapy is essential for recovery and prognosis. The optimal treatment regimen has not been defined, but methotrexate-based chemotherapy regimens are considered the standard treatment approach for induction treatment. Novel, targeted agents have recently been introduced into the therapeutic arsenal.

Diffusion-weighted MR imaging histogram analysis in HIV positive and negative patients with primary central nervous system lymphoma as a predictor of outcome and tumor proliferation

INTRODUCTION

Ki-67 expression, a marker of tumor proliferation, is considered a prognostic factor in primary CNS lymphoma (PCNSL). Apparent diffusion coefficient (ADC) parameters have also been proposed as imaging biomarkers for tumor progression and proliferative activity in various malignancies. The aim of this study is to investigate the correlation between ADC parameters, Ki-67 expression, overall survival (OS) and progression free survival (PFS) in PCNSL.

MATERIALS AND METHODS

Patients diagnosed with PCNSL at MD Anderson Cancer Center between Mar 2000 and Jul 2016 and at Ben Taub Hospital between Jan 2012 and Dec 2016 were retrospectively studied. Co-registered ADC maps and post-contrast images underwent whole tumor segmentation. Normalized ADC parameters (nADC) were calculated as the ratio to normal white matter. Percentiles of nADC were calculated and were correlated with Ki-67 using Pearson's correlation coefficient and clinical outcomes (OS and PFS) using Cox proportional hazards models.

RESULTS

Selection criteria yielded 90 patients, 23 patients living with HIV (PLWH) and 67 immunocompetent patients. Above median values for nADC_mean, nADC₁₅, nADC₇₅ and nADC₉₅ were associated with improved OS in all patients (p < 0.05). Above median values for nADC_min, nADC_mean, nADC₁, nADC₅ and kurtosis were associated with improved PFS in all patients (p < 0.05). In patients with available Ki-67 expression data (n = 22), nADC_mean, nADC₁₅ and nADC₇₅ inversely correlated with Ki-67 expression (p < 0.05). For PLWH, there was no correlation between ADC parameters and Ki-67 expression or clinical outcomes.

CONCLUSIONS

ADC histogram analysis can predict tumor proliferation and survival in immunocompetent patients with PCNSL, but with limited utility in PLWH.

Challenges in the Treatment of Newly Diagnosed and Recurrent Primary Central Nervous System Lymphoma

Primary central nervous system lymphomas (PCNSLs) are rare cancers of the central nervous system (CNS) and are predominantly diffuse large B-cell lymphomas of the activated B-cell (ABC) subtype. They typically present in the sixth and seventh decade of life, with the highest incidence among patients aged >75 years. Although many different regimens have demonstrated efficacy in newly diagnosed and relapsed or refractory PCNSL, there have been few randomized prospective trials, and most recommendations and treatment decisions are based on single-arm phase II trials or even retrospective studies. High-dose methotrexate (HD-MTX; 3-8 g/m2) is the backbone of preferred standard induction regimens. Various effective regimens with different toxicity profiles can be considered that combine other chemotherapies and/or rituximab with HD-MTX, but there is currently no consensus for a single preferred regimen. There is controversy about the role of various consolidation therapies for patients who respond to HD-MTX-based induction therapy. For patients with relapsed or refractory PCNSL who previously experienced response to HD-MTX, repeat treatment with HD-MTX-based therapy can be considered depending on the timing of recurrence. Other more novel and less toxic regimens have been developed that show efficacy in recurrent disease, including ibrutinib, or lenalidomide ± rituximab. There is uniform agreement to delay or avoid whole-brain radiation therapy due to concerns for significant neurotoxicity if a reasonable systemic treatment option exists. This article aims to provide a clinically practical approach to PCNSL, including special considerations for older patients and those with impaired renal function. The benefits and risks of HD-MTX or high-dose chemotherapy with autologous stem cell transplantation versus other, better tolerated strategies are also discussed. In all settings, the preferred treatment is always enrollment in a clinical trial if one is available.

Impact of contemporary regimens on the outcomes and toxicity of primary CNS lymphoma: a single-center retrospective analysis of 73 patients

INTRODUCTION

Primary central nervous system lymphoma (PCNSL) is a rare disease with a dismal prognosis compared to its systemic large B-cell lymphoma counterpart. Real world data are limited, when considering a uniform backbone treatment.

METHODS

A retrospective study of all adult patients treated sequentially with a high-dose methotrexate (HD MTX)-based regimen in a single tertiary medical center between 2003 and 2019.

RESULTS

The 2015-2019 period differed from its predecessor in that most patients were treated with an HD MTX-based polychemotherapy regimen as opposed to HD MTX monotherapy (81% vs. 13%, P < .001), rituximab was given as standard of care (100% vs. 56%, P < .01), and most induction-responsive patients received consolidation treatment (70% vs. 18%, P = .01). The median progression-free and overall survival (OS) for the entire cohort (n = 73, mean age 64 years) was 9.9 and 29.8 months, respectively. Patients diagnosed between 2015 and 2019 had superior OS (P = .03) compared to those treated earlier. An interim partial response (PR) state, documented after two cycles of chemotherapy, was associated with increased incidence of progression, with only 33% of those patients achieving end-of-induction complete response. Twenty-three percent of patients developed thrombotic events and 44% developed grade 3-4 infections. HD MTX-based polychemotherapy induction was associated with both increase in thrombotic and infection incidence.

CONCLUSIONS

Contemporary HD MTX-based combination therapies suggestively improved the outcomes for PCNSL, but at a cost of increased incidence of toxicity. Patients who achieve an interim PR status are at a high risk for treatment failure.

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.

Dynamic contrast-enhanced magnetic resonance imaging biomarkers predict chemotherapeutic responses and survival in primary central-nervous-system lymphoma

OBJECTIVES

To evaluate the utility of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in predicting the response of chemotherapy and clinical outcomes in primary central-nervous-system lymphoma (PCNSL) patients.

METHODS

DCE-MRI in 56 patients enrolled in a prospective study was performed at baseline and 30 days after treatment from 2016 to 2019. Multivariate logistic regression analyses were performed to assess risk factors for tumor responses. The predictive values of related parameters derived from DCE were analyzed via receiver operating characteristic (ROC) curve analysis. To evaluate prognostic factors, the Kaplan-Meier survival analysis with log-rank tests and Cox regression tests were analyzed.

RESULTS

K^trans and V_e were higher in the non-response group than in the response group (p < 0.05). The K^trans and the percentage of K^trans decreased after 30 days of treatment were independent predictors of chemotherapy responses (p = 0.034 and p = 0.019). ROC analysis indicated that the cut-off point of K^trans for predicting chemotherapeutic responses was 0.353 min^-1 (AUC, 0.941; 95% CI, 0.87-1; p < 0.001) and percentage of K^trans decreased after 30 days of treatment was 15.2% (AUC, 0.858; 95% CI, 0.742-0.970; p < 0.001). The greater decrease in K^trans correlated with a longer progression-free survival (PFS) (χ² = 13.203, p < 0.001). The higher K^trans was an independent predictor for shorter PFS (hazard ratio, 10.182; 95% CI, 2.510-41.300; p = 0.001).

CONCLUSIONS

K^trans and K^trans change measured by DCE-MRI were reliable biomarkers for predicting chemotherapy responses in PCNSL patients.

KEY POINTS

• Baseline K^trans and greater decrease in K^trans can predict chemotherapeutic efficacy. • DCE-MRI provides quantitative parameters reflecting the tumor microenvironment. • Targeted treatment therapy can be given with more evidence in the future.

An atypical presentation of primary central nervous system lymphoma: A case report

RATIONALE

Primary central nervous system lymphoma (PCNSL) involving the choroid plexus is exceedingly rare. The differential diagnosis for choroid plexus enhancing lesions in addition to lymphoma includes infections, sarcoidosis, tuberculosis, papilloma, meningioma, subependymoma, and metastatic lesions.

PATIENT CONCERNS

A 71-year-old man presented with 3 days of episodic memory loss and gait disturbance. Brain magnetic resonance imaging showed homogenously enhancing lesions with mildly restricted diffusion and T2 hypointensity in the lateral ventricles, as well as T2 hyperintensity and enhancement in the right hippocampus. His episodic memory loss was thought to be secondary to subclinical focal seizures, supported by EEG revealing right temporal lobe epileptiform discharges.

DIAGNOSES

Large B-cell lymphoma, nongerminal center type was revealed on pathological examination.

INTERVENTIONS

Stereotactic biopsy of his right thalamic lesion was performed.

OUTCOMES

The patient underwent induction therapy with high-dose methotrexate, temozolomide, and rituximab, which resulted in complete resolution of the enhancing lesions. He then underwent conditioning chemotherapy with carmustine and thiotepa, followed by autologous stem cell transplantation. His PCNSL remains in remission 42 weeks after the onset of symptoms.

LESSONS

We report a patient with multifocal PCNSL involving the choroid plexus, who presented with abnormal gait and episodic confusion and memory loss. PCNSL should be considered in the differential diagnosis of acute encephalopathy among immunocompetent older individuals who have choroid plexus enhancing lesions.

Consolidative or palliative whole brain radiation for secondary CNS diffuse large B-Cell lymphoma

We analyzed 25 patients receiving whole brain radiation (WBRT) for secondary CNS lymphoma (SCNSL), grouped by consolidative intent (after complete/partial response, n = 13) vs. palliative intent (initial CNS treatment, primary refractory disease, or CNS progression, n = 12). Median WBRT dose for the consolidative and palliative cohorts were 24 Gy and 30 Gy, respectively. For 13 patients receiving consolidative WBRT, median OS was 24 months from WBRT and 2-year OS was 64%. Three patients had CNS relapse at 2, 9, and 24 months after consolidative WBRT. For 12 patients receiving palliative WBRT, median OS was 3 months from WBRT and two-year OS was 8%. All 10 patients with neurologic symptoms had documented improvement. In conclusion, consolidative WBRT after chemotherapy response led to reasonable long-term survival and may be an effective strategy for SCNSL, especially transplant-ineligible patients and/or isolated CNS recurrence. Palliative WBRT effectively improved neurologic symptoms, but survival was usually only months.

Chemoradiotherapy with temozolomide after high-dose methotrexate for primary CNS lymphoma: a multicenter phase I study of a response-adapted strategy

This study aimed to define the maximum tolerated dose (MTD) of temozolomide (TMZ) concurrent with radiotherapy (RT) after high-dose methotrexate (HD-MTX) for newly diagnosed primary central nervous system lymphoma (PCNSL). Adult patients with PCNSL were treated according to a response-adapted strategy. HD-MTX (3.5 g/m²) was followed by concomitant RT and escalating TMZ (50-60-75 mg/m²/day, 5 days/week). The total radiation dose was modulated according to the patient's response to HD-MTX. All patients received 30 Gy to the whole brain plus leptomeninges to C2, including the third posterior of the orbital cavity (clinical target volume 2; CTV2), plus 6, 10, or 16 Gy to the primary site, including the residual mass (CTV1), if a complete response (CR), partial response (PR)/stable disease (SD), or progressive disease (PD) was observed, respectively. Acute toxicities were graded according to the RTOG-EORTC criteria. Dose-limiting toxicity (DLT) was defined as grade 4 hematological toxicity or grade 3-4 hepatic toxicity, although 75 mg/m²/day was the maximum dose regardless of DLT. Neurocognitive function was evaluated using the Mini-Mental State Examination. Three patients were enrolled at each TMZ dose level (total = 9 patients). Twelve lesions were treated. Six patients received 2 cycles of HD-MTX, while 3 received only 1 cycle because of hepatic or renal toxicity. All patients completed chemoradiotherapy without interruptions. No DLT events were recorded. TMZ appears to be tolerable at a dose of 75 mg/m²/day when administered concomitantly with radiotherapy and after HD-MTX.

Diagnostic Yield of Body CT and Whole-Body FDG PET/CT for Initial Systemic Staging in Patients With Suspected Primary CNS Lymphoma: A Systematic Review and Meta-Analysis

BACKGROUND. Several guidelines recommend body imaging for the initial work-up of patients with suspected primary CNS lymphoma, to exclude subclinical systemic involvement. However, to our knowledge, the diagnostic yield of body CT (contrast-enhanced CT of the chest, abdomen, and pelvis) and whole-body FDG PET/CT for the evaluation of subclinical systemic lymphoma has not yet been systematically evaluated. OBJECTIVE. The purpose of this study was to investigate and compare the diagnostic yield of body CT and whole-body FDG PET/CT in detecting subclinical systemic lymphoma in patients with suspected primary CNS lymphoma. EVIDENCE ACQUISITION. A systematic search of the MEDLINE and EMBASE databases through July 5, 2020, was conducted to identify studies evaluating the diagnostic yield of body CT or whole-body FDG PET/CT in detecting subclinical systemic lymphoma in patients with suspected primary CNS lymphoma. Pooled estimates of the diagnostic yield of both imaging modalities were calculated using the DerSimonian and Laird random-effects model. The false referral rate and the rate of incidental secondary malignancy were also pooled. EVIDENCE SYNTHESIS. Nine original articles on studies evaluating a total of 1040 patients were included. In detecting subclinical systemic lymphoma, the pooled diagnostic yields of body CT and whole-body FDG PET/CT were 2.5% (95% CI, 1.5-3.9%) and 4.9% (95% CI, 2.8-8.5%), respectively. In the subgroup analysis, the diagnostic yield of whole-body FDG PET/CT was significantly higher than that of body CT (p = .03). Four studies reported changes in the management plan: the R-CHOP (rituximab, cyclophosphamide, hydroxydaunorubicin, vincristine, and prednisone) regimen with or without radiation therapy was added if extracranial lymphoma involvement was detected by body CT or whole-body FDG PET/CT. The pooled false referral rate of whole-body FDG PET/CT was 5.3% (95% CI, 2.2-12.0%). The pooled rate of incidental secondary malignancy detected on whole-body FDG PET/CT was 3.1% (95% CI, 1.7-5.6%). CONCLUSION. Body imaging should be used in the initial workup of patients with suspected primary CNS lymphoma, to exclude systemic involvement. Whole-body FDG PET/CT may be a better alternative to body CT. CLINICAL IMPACT. Our results support current National Comprehensive Cancer Network guidelines for the use of body imaging to exclude subclinical systemic involvement in patients with suspected primary CNS lymphoma.

Outcomes of Autologous Stem Cell Transplant Consolidation in Primary Central Nervous System Lymphoma: A Mayo Clinic Experience

A paucity of randomized phase III clinical trials in primary central nervous system lymphoma (PCNSL) has resulted in no uniform consensus on the optimal strategy for consolidation and conditioning regimens for autologous stem cell transplant (ASCT). The past 2 decades have witnessed a preference for thiotepa (TT)-based conditioning regimens due to superior central nervous system penetration. We retrospectively evaluated outcomes of patients with PCNSL who underwent ASCT at Mayo Clinic, Rochester over the past 2 decades, and the impact of TT-based conditioning regimens. Fifty-six patients underwent transplant for PCNSL, with 25 and 31 patients receiving BEAM (non-thiotepa) and carmustine (BCNU)/TT-based conditioning, respectively. All patients received high-dose methotrexate-based induction therapy. While the BCNU/TT group had higher risk disease features such as high International Extranodal Lymphoma Study Group prognostic score, elevated cerebrospinal fluid protein, and older patient population, there was no significant difference at 2 years post-transplant in progression-free survival (BEAM 68.0% [46.1% to 82.5%] versus BCNU/TT, 65.5% [45.2% to 79.8%], P = .99) or overall survival (OS) (84.0% [62.8% to 93.7%] in the BEAM group versus 81.6% [61.3% to 91.9%] in the BCNU/TT group, P = .95). Disease response status before transplant significantly affected the outcomes as those in complete remission had an OS at 2 years post-transplant of 94.7% (68.1% to 99.2%) in the BEAM group and 90.5% (67.0% to 97.5%) in the BCNU/TT group compared with those in partial response, 57.1% (17.2% to 83.7%) in BCNU/TT group and 50.0% (11.1% to 80.4%) in the BEAM group, respectively (P < .0001). Our retrospective cohort adds to the currently available literature and identifies the disease status before transplant as a significant factor affecting survival.

Recent advances in the management of primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is a rare subtype of extranodal lymphoma primarily involving the brain, spinal cord, or leptomeninges. PCNSL is associated with a relatively poor prognosis compared to other extranodal diffuse large B-cell lymphomas. However, methotrexate-based induction chemotherapy followed by consolidative chemotherapy or high-dose therapy and autologous stem cell transplantation has improved the survival outcome, together with reduced neurotoxicity. Recent studies found that aberrant activation of the B-cell receptor-signaling pathway and activation of the NF-κB are frequent genetic alterations and could be good targets for the treatment of PCNSL. Herein, we have reviewed the current status and recent advances in the biology and management of PCNSL.

On point in primary CNS lymphoma

Primary CNS lymphoma (PCNSL) is an aggressive brain tumor that represents a significant challenge both to elucidate its biological pathogenesis as well as to develop definitive precision medicines with minimal collateral toxicity. We highlight the key issues in diagnosis and treatment and focus on emerging technologies, current options among consolidation strategies, and biological agents. We anticipate that further development of molecular diagnostics and molecular imaging approaches that elucidate minimal residual disease in brain parenchyma, leptomeninges, intraocular compartments and even bone marrow will greatly impact the delivery and timing of cytotoxic and biological therapies. Implementation of these approaches is likely essential to clarify ongoing discrepancies in the interpretation of clinical trial results that currently are based on relatively unrefined definitions of response. While the results of early phase investigations involving ibrutinib and the IMiD agents, lenalidomide, pomalidomide, as well as avadomide, strongly support the hypothesis that the B-cell receptor (BCR) pathway, involving MYD88 and CD79B and NF-kB activation, is critical to the pathogenesis of PCNSL, much work is needed to elucidate mechanisms of resistance. Similarly, development of strategies to overcome immunosuppressive mechanisms that are upregulated in the tumor microenvironment is a high priority. Finally, ongoing evidence supports the hypothesis that the blood-brain barrier represents a significant impediment to efficient brain tumor penetration of novel therapeutic agents and innovative strategies of drug delivery remain essential to further improve outcomes.

Histone deacetylase inhibition enhances the therapeutic effects of methotrexate on primary central nervous system lymphoma

Background

Polyglutamylation is a reversible protein modification that commonly occurs in tumor cells. Methotrexate (MTX) in tumor cells is polyglutamylated and strongly binds to dihydrofolate reductase (DHFR) without competitive inhibition by leucovorin. Therefore, tumor cells with high polyglutamylation levels are supposed to be selectively killed, whereas normal cells with lower polyglutamylation are rescued by leucovorin. This study investigated the combined effects of MTX plus histone deacetylase inhibitors (HDACIs), which upregulate MTX polyglutamylation, in primary central nervous system lymphoma (PCNSL).

Methods

We evaluated cell viability after MTX treatment and leucovorin rescue and compared the expression of folylpolyglutamate synthetase (FPGS), γ-glutamyl hydrolase (GGH), and DHFR in 2 human PCNSL-derived cell lines (HKBML and TK) and a human Burkitt lymphoma cell line (TL-1). Combination treatments were created using 4 HDACIs: panobinostat, vorinostat, sodium butyrate, and valproic acid. The expression of DHFR was examined as well as ratios of FPGS/GGH expression. The combined effects of MTX plus HDACIs were evaluated using a cell viability assay, mass spectroscopy imaging, and subcutaneous and intracranial xenograft models.

Results

HDACIs upregulated the ratio of FPGS/GGH expression resulting in increased polyglutamylation of MTX, but also downregulated expression of the target molecule of MTX: DHFR. The combination of MTX and vorinostat decreased cell viability in vitro (P < .05) and tumor volumes in a subcutaneous model (P < .0001), and prolonged survival in an intracranial model (P < .01), relative to controls.

Conclusion

HDACIs enhanced the therapeutic effect of MTX through increased polyglutamylation of MTX and concomitant downregulation of DHFR expression.

Rare Primary Central Nervous System Tumors in Adults: An Overview

Overall, tumors of primary central nervous system (CNS) are quite common in adults with an incidence rate close to 30 new cases/100,000 inhabitants per year. Significant clinical and biological advances have been accomplished in the most common adult primary CNS tumors (i.e., diffuse gliomas). However, most CNS tumor subtypes are rare with an incidence rate below the threshold defining rare disease of 6.0 new cases/100,000 inhabitants per year. Close to 150 entities of primary CNS tumors have now been identified by the novel integrated histomolecular classification published by the World Health Organization (WHO) and its updates by the c-IMPACT NOW consortium (the Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy). While these entities can be better classified into smaller groups either by their histomolecular features and/or by their location, assessing their treatment by clinical trials and improving the survival of patients remain challenging. Despite these tumors are rare, research, and advances remain slower compared to diffuse gliomas for instance. In some cases (i.e., ependymoma, medulloblastoma) the understanding is high because single or few driver mutations have been defined. The European Union has launched European Reference Networks (ERNs) dedicated to support advances on the clinical side of rare diseases including rare cancers. The ERN for rare solid adult tumors is termed EURACAN. Within EURACAN, Domain 10 brings together the European patient advocacy groups (ePAGs) and physicians dedicated to improving outcomes in rare primary CNS tumors and also aims at supporting research, care and teaching in the field. In this review, we discuss the relevant biological and clinical characteristics, clinical management of patients, and research directions for the following types of rare primary CNS tumors: medulloblastoma, pineal region tumors, glioneuronal and rare glial tumors, ependymal tumors, grade III meningioma and mesenchymal tumors, primary central nervous system lymphoma, germ cell tumors, spinal cord tumors and rare pituitary tumors.

Molecular profiling of primary central nervous system lymphomas - predictive and prognostic value?

PURPOSE OF REVIEW

Primary central nervous system lymphoma (PCNSL) is a rare but aggressive variant of non-Hodgkin lymphoma. The diagnostic gold standard remains the pathologic review of tumor tissue mainly collected though biopsies. The majority of PCNSL are diffuse large B cell lymphoma (DLBCL). Biopsies are invasive procedures, and there have been efforts to develop minimally invasive diagnostic testing using serum and cerebral spinal fluid. This article reviews multiple markers that could potentially serve as future diagnostic tools and predictors of treatment response.

RECENT FINDINGS

Many studies have attempted to classify DLBCL into different subtypes for prognostic purposes using methods such as immunohistochemistry. PCNSL often falls under the activated B-cell-like subgroup, and further genomic sequencing has identified alterations in genes within the B-cell receptor signaling axis at increased frequencies. Two such genes, MYD88 and CD79B, implicate the involvement of the NF-kB (nuclear factor kappa-light-chain enhancer of activated B cells) pathway, and targeted agents to this pathway are currently being used in the treatment of relapsed/refractory PCNSL.

SUMMARY

Although recent genomic profiling of PCNSL has increased the understanding of drivers in this disease and has also led to the introduction of targeted inhibitors, these markers have not yet been used for diagnostic and/or prognostic purposes. Further studies will need to evaluate if they hold great diagnostic potential.

Use of FDG-PET/CT for systemic assessment of suspected primary central nervous system lymphoma: a LOC study

INTRODUCTION

Primary Central Nervous System Lymphoma (PCNSL) is a rare disease with different therapeutic implications than systemic lymphoma. In this study, we evaluated whole-body ¹⁸FDG-PET/CT for pre-chemotherapy imaging of suspected PCNSL.

METHODS

One hundred and thirty consecutive immunocompetent patients were retrospectively included. The results of initial ¹⁸FDG-PET/CT, contrast-enhanced CT (CeCT) and bone marrow biopsy (BMB) when available were compared to a gold standard based on pathological diagnosis or follow-up.

RESULTS

CNS lesion pathology showed large B-cell lymphoma in 95% of patients, including 11 patients with primary vitro-retinal lymphoma. Ten patients (8%) where ultimately diagnosed with systemic lymphoma involvement, including five pathologically confirmed cases, all of which were detected by ¹⁸FDG-PET/CT. ¹⁸FDG-PET/CT showed incidental systemic findings unrelated to lymphoma in 14% of patients. An SUVmax threshold of nine enabled good discrimination between systemic lymphoma and other lesions (sensitivity 92% and specificity 89%). CeCT and BMB performed in 108 and 77 patients respectively revealed systemic lesions in only three patients.

CONCLUSION

¹⁸FDG-PET/CT detected concomitant occult systemic involvement in a non-negligible proportion of suspected PCNSL cases (8%). In this setting its sensitivity is higher than that of CeCT. All of our patients ultimately diagnosed with concomitant systemic involvement had positive ¹⁸FDG-PET/CT. We believe it constitutes a safe one-stop shop evaluation for the systemic pre-treatment imaging of suspected PCNSL.

Usefulness of carbon-11-labeled methionine positron-emission tomography for assessing the treatment response of primary central nervous system lymphoma

BACKGROUND

Primary central nervous system lymphoma (PCNSL) responds relatively quickly to chemotherapy or radiotherapy. However, determination of a complete response after treatment is often difficult because of extremely light residual contrast enhancement on magnetic resonance images due to the effects of microhemorrhages and scar tissue formation. These small enhancing lesions define an unconfirmed complete response. The aim of this study was to investigate the usefulness of carbon-11-labeled methionine (11C-Met) positron-emission tomography (PET) for determining the treatment response of PCNSL.

METHODS

Data for 36 patients who were treated for PCNSL between 2011 and 2015 and underwent magnetic resonance imaging and 11C-Met PET were reviewed. Magnetic resonance imaging findings were classified as complete response, unconfirmed complete response, and tumor mass (a composite of partial response, stable disease and progressive disease). PET images were evaluated, standardized uptake values were quantified, and the tumor-to-normal tissue count ratio (TNR) was calculated. Receiver operating characteristic curves were generated to determine the optimal cutoff TNRs.

RESULTS

The optimal TNRs for differentiating complete response and unconfirmed complete response from tumor mass were 1.83 (area under the curve, 0.951) and 1.80 (area under the curve, 0.932), respectively. The corresponding sensitivity and specificity values for the diagnosis of tumor mass were 82.4 and 100%, respectively, in the complete response group and 85.3 and 85%, respectively, in the unconfirmed complete response group.

CONCLUSIONS

A TNR of ≥1.80 can aid in the detection of active PCNSL using 11C-Met PET. Thus, 11C-Met-PET may be a useful tool for accurate evaluation of the treatment efficacy in PCNSL.

Comprehensive approach to diagnosis and treatment of newly diagnosed primary CNS lymphoma

Primary central nervous system lymphoma (PCNSL) is a rare form of non-Hodgkin lymphoma that affects the brain parenchyma, spinal cord, eyes, and cerebrospinal fluid without evidence of systemic, non-CNS involvement. PCNSL is uncommon and only a few randomized trials have been completed in the first-line setting. Over the past decades, the prognosis of PCNSL has improved, mainly due to the introduction and widespread use of high-dose methotrexate, which is now the backbone of all first-line treatment polychemotherapy regimens. Despite this progress, durable remission is recorded in only 50% of patients, and therapy can be associated with significant late neurotoxicity. Here, we overview the epidemiology, clinical presentation, staging evaluation, prognosis, and current up-to-date treatment of immunocompetent PCNSL patients.

Health-related quality of life after chemotherapy with or without rituximab in primary central nervous system lymphoma patients: results from a randomised phase III study

BACKGROUND

The impact of rituximab on health-related quality of life (HRQoL) in primary central nervous system lymphoma patients is not well known. We determined the impact of rituximab added to standard high-dose methotrexate-based treatment on HRQoL in patients in a large randomised trial.

PATIENTS AND METHODS

Patients from a large phase III trial (HOVON 105/ALLG NHL 24), randomly assigned to receive standard chemotherapy with or without rituximab and followed by 30 Gy whole brain radiotherapy (WBRT) in patients ≤60 years, completed the EORTC QLQ-C30 and QLQ-BN20 questionnaires before and during treatment, and up to 24 months of follow-up or progression. Differences between treatment arms over time in global health status, role functioning, social functioning, fatigue, and motor dysfunction were assessed. Differences ≥10 points were deemed clinically relevant. The effect of WBRT on HRQoL was analysed in irradiated patients.

RESULTS

A total of 160/175 patients eligible for the HRQoL study completed at least one questionnaire and were included. Over time, scores improved statistically significantly and were clinically relevant in both arms. Between arms, there were no differences on any scale (range: -3.8 to +4.0). Scores on all scales were improved to a clinically relevant extent at 12 and 24 months compared with baseline in both arms, except for fatigue and motor dysfunction at 12 months (-7.4 and -8.8, respectively). In irradiated patients (n = 59), scores in all preselected scales, except motor dysfunction, remained stable up to 24 months compared with shortly after WBRT, overall mean difference ranging between 0.02 and 4.570.

CONCLUSION

Compared with baseline, treatment resulted in improved HRQoL scores. The addition of rituximab to standard chemotherapy did not impact HRQoL over time. WBRT did not result in deterioration of HRQoL in the first 2 years.

Clinicopathological characteristics of primary central nervous system lymphoma with low 18F-fludeoxyglucose uptake on brain positron emission tomography

Primary central nervous system lymphoma (PCNSL) typically shows a strong uptake of F-fludeoxyglucose (FDG) imaged by positron emission tomography (PET). Uncommonly, PCNSL demonstrates a low uptake on FDG PET. We investigated the clinicopathological characteristics of the unusual cases of PCNSL with low FDG uptake.We retrospectively enrolled 104 consecutive patients with newly diagnosed PCNSL who underwent baseline brain FDG PET. The degree of FDG uptake of PCNSL was visually scored by 4 grades (0, ≤contralateral white matter; 1, >contralateral white matter and <contralateral gray matter; 2, = contralateral gray matter; 3, >contralateral gray matter). Grades 0-2 were considered as PCNSL with low uptake. We investigated association of low uptake of PCNSL with the following clinicopathological factors: age, sex, steroid treatment, lactate dehydrogenase level, cerebrospinal fluid protein level, condition of PET scanning, immunohistochemical markers (cluster of differentiation 10 [CD10], B-cell lymphoma 6 [BCL-6], B-cell lymphoma 2 [BCL-2], multiple myeloma oncogene 1 [MUM1], Epstein-Barr virus [EBV] protein, and Ki67), location of lesions, tumor size, multiplicity of lesions, involvement of deep brain structures, and cystic or necrotic appearance of lesions.Of the 104 patients with PCNSL, 14 patients (13.5%) showed PCNSL with low FDG uptake on PET. Among various clinicopathological factors, MUM1 negativity was the only factor associated with low FDG uptake PCNSL by univariate (P = .002) and multivariate analysis (P = .007).This study suggests that the different clinicopathological characteristics between patients with high uptake and low uptake of PCNSL on FDG PET is closely associated with lack of MUM1, a protein known to be a crucial regulator of B-cell development and tumorigenesis.

CXCR4-Targeted PET Imaging of Central Nervous System B-Cell Lymphoma

C-X-C chemokine receptor 4 (CXCR4) is a transmembrane chemokine receptor involved in growth, survival, and dissemination of cancer, including aggressive B-cell lymphoma. MRI is the standard imaging technology for central nervous system (CNS) involvement of B-cell lymphoma and provides high sensitivity but moderate specificity. Therefore, novel molecular and functional imaging strategies are urgently required. Methods: In this proof-of-concept study, 11 patients with lymphoma of the CNS (8 primary and 3 secondary involvement) were imaged with the CXCR4-directed PET tracer ⁶⁸Ga-pentixafor. To evaluate the predictive value of this imaging modality, treatment response, as determined by MRI, was correlated with quantification of CXCR4 expression by ⁶⁸Ga-pentixafor PET in vivo before initiation of treatment in 7 of 11 patients. Results: ⁶⁸Ga-pentixafor PET showed excellent contrast with the surrounding brain parenchyma in all patients with active disease. Furthermore, initial CXCR4 uptake determined by PET correlated with subsequent treatment response as assessed by MRI. Conclusion: ⁶⁸Ga-pentixafor PET represents a novel diagnostic tool for CNS lymphoma with potential implications for theranostic approaches as well as response and risk assessment.

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.

The Impact of Early Corticosteroid Pretreatment Before Initiation of Chemotherapy in Patients With Primary Central Nervous System Lymphoma

BACKGROUND

The optimal timing of corticosteroid (CS) treatment in patients with primary central nervous system (CNS) lymphoma (PCNSL) remains controversial. While poor clinical presentation may justify early treatment with CS, this may ultimately result in reduced concentrations of chemotherapeutic agents via perturbations in the permeability of the blood-brain barrier.

OBJECTIVE

To investigate whether early CS exposure is associated with beneficial outcomes and/or reduced occurrence of adverse events as opposed to delayed/concomitant administration.

METHODS

Herein we performed a retrospective observational analysis using patients that were prospectively entered into a database. All patients whom were admitted to the University Hospital between 2009 and 2015 with newly diagnosed PCNSL were included within our study.

RESULTS

Our cohort included 50 consecutive patients diagnosed with PCNSL; of these, in 30 patients CS administration was initiated prior to chemotherapy (early), whilst in the remaining 20 patients CS administration was initiated concomitantly with their chemotherapeutic regimen (concomitant). Within the early vs concomitant CS administration groups, no significant differences were observed with regard to progression-free survival (PFS) (P = .81), overall survival (OS) (P = .75), or remission (P = .68; odds ratio 0.76 and confidence interval [95%] 0.22-2.71). Critically, the timing of CS initiation was not associated with either PFS (P = .81) or PFS (P = .75).

CONCLUSION

Early CS administration was not associated with a deterioration in response to chemotherapy, PFS, or OS. As such, administration of CS prior to initiation of chemotherapy is both reasonable and safe for patients with newly diagnosed PCNSL.

Primary dural lymphomas: Clinical presentation, management, and outcome

BACKGROUND

Clinical experience is limited for primary central nervous system (CNS) lymphoma that arises from the dura mater, which is denoted with the term primary dural lymphoma (PDL). This study was aimed at determining the relative incidence, presentation, and outcomes of PDL.

METHODS

The institutional databases of the Divisions of Neuro-Oncology at the Massachusetts General Hospital and the Yale School of Medicine were retrospectively searched for patients with primary CNS lymphoma. Patients with pathologically confirmed dural lymphoma and no evidence of primary cerebral or systemic involvement were identified. Clinical data, diagnostic findings, treatments, and outcomes were recorded.

RESULTS

A total of 20 patients with PDL were identified, and they represented 6.3% of the individuals with primary CNS lymphomas (20 of 316). Histopathological examination of PDL revealed the following underlying subtypes: diffuse large B-cell lymphoma (10 of 20 patients), marginal zone lymphoma (6 of 20), follicular lymphoma (2 of 20), undefined B-cell non-Hodgkin lymphoma (1 of 20), and T-cell non-Hodgkin lymphoma (1 of 20). On imaging, all tumors appeared as extra-axial masses with avid contrast enhancement and mostly mimicked meningioma. The median apparent diffusion coefficient value was 667 ± 26 mm² /s. Cerebrospinal fluid analyses and symptoms were nonspecific, and the diagnosis rested on tissue analysis. Therapeutic approaches included surgery, radiotherapy, and chemotherapy. The median overall survival was not reached after 5 years. Three patients were deceased at database closure because of tumor progression. The extent of tumor resection correlated positively with overall survival (P = .044).

CONCLUSIONS

PDL is a rare variant of primary CNS lymphoma that can be radiographically mistaken for meningioma. The outcome is excellent with multimodality treatment, and aggressive surgery may convey a survival advantage in select cases.

Patterns of relapse after successful completion of initial therapy in primary central nervous system lymphoma: a case series

PURPOSE

Primary central nervous system lymphoma (PCNSL) is a subtype of non-Hodgkin's lymphoma that involves the brain, spinal cord, or leptomeninges, without evidence of systemic disease. This rare disease accounts for ~ 3% of all primary central nervous system (CNS) tumors. Methotrexate-based regimens are the standard of care for this disease with overall survival rates ranging from 14 to 55 months. Relapse after apparent complete remission can occur. We sought to understand the outcomes of patients who relapsed.

METHODS

This is an IRB-approved investigation of patients treated at our institution between 12/31/2004 and 10/12/2016. We retrospectively identified all cases of PCNSL as part of a database registry and evaluated these cases for demographic information, absence or presence of relapse, location of relapse, treatment regimens, and median relapse-free survival.

RESULTS

This analysis identified 44 patients with a pathologically confirmed diagnosis of PCNSL. Mean age at diagnosis was 63.1 years (range 20-86, SD = 13.2 years). Of the 44 patients, 28 patients successfully completed an initial treatment regimen without recurrence or toxicity that required a change in therapy. Relapse occurred in 11 patients with the location of relapse being in the CNS only (n = 5), vitreous fluid only (n = 1), outside CNS only (n = 3), or a combination of CNS and outside of the CNS (n = 2). Sites of relapse outside of the CNS included testes (n = 1), lung (n = 1), adrenal gland (n = 1), kidney/adrenal gland (n = 1), and retroperitoneum (n = 1). Median relapse-free survival after successful completion of therapy was 6.7 years (95% CI 1.1, 12.6).

CONCLUSION

After successful initial treatment, PCNSL has a propensity to relapse, and this relapse can occur both inside and outside of the CNS. Vigilant monitoring of off-treatment patients with a history of PCNSL is necessary to guide early diagnosis of relapse and to initiate aggressive treatment.

Serum levels of soluble programmed death-ligand 1 (sPD-L1) in patients with primary central nervous system diffuse large B-cell lymphoma

Background

The interaction of programmed death-1 protein (PD-1) and programmed death-1 ligand (PD-L1) produces immunosuppressive activity, protecting tumor cells from anti-tumor immunity and possibly releasing soluble PD-L1 (sPD-L1) from PD-L1 expressing tumor cells. Therefore, we measured serum levels of sPD-L1 in patients with primary central nervous system lymphoma (PCNSL) and explored its clinical implications.

Methods

Sixty-eight patients with newly diagnosed PCNSL had diffuse large B-cell lymphoma and were treated with high-dose methotrexate-containing chemotherapy. The measurement of sPD-L1 and cytokines was performed using serum samples archived at diagnosis, and the tissue expression of PD-L1 was also analyzed from archived paraffin-embedded tissue blocks. Disease relapse, progression-free survival (PFS), and overall survival (OS) were analyzed according to the extent of sPD-L1 in serum and PD-L1 in tissue.

Results

The median level of serum sPD-L1 (0.429 ng/mL) was higher than in healthy control patients (0.364 ng/mL). The occurrence of relapse was more frequent in the high sPD-L1 (78%) than the low sPD-L1 group (50%), though the groups did not have different clinical or pathological characteristics at diagnosis. As a result, the OS and PFS for the high sPD-L1 group were significantly lower than those in the low group. PD-L1-positive tumor cells were found in 35 patients (67%), and the extent of PD-L1-postive tumor cells was positively associated with serum sPD-L1 levels (r = 0.299, P = 0.031). Among the 34 cytokines analyzed, only the serum level of IL-7 correlated with the serum level of sPD-L1 (r = 0.521, P < 0.001).

Conclusions

Serum levels of sPD-L1 could reflect the expression of PD-L1 in PCNSL tumor cells and predict patient survival outcomes. Therefore, sPD-L1 in serum could be a feasible biomarker for determining a risk-adapted treatment strategy for PCNSL patients.

Trial registration

The study population was patients who were diagnosed with PCNSL between January 2009 and February 2017 and registered for our prospective cohort studies after providing written informed consent (ClinicalTrials.gov: NCT00822731 [date of registration - January 14, 2009] and NCT01877109 [date of registration - June 13, 2013]).

Eye involvement in primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) may manifest initially in the eye (termed vitreoretinal lymphoma or VRL) or in non-ocular CNS compartments, or in both. The nature of the onset of PCNSL implies two clinical specialists - ophthalmologists and neuro-oncologists - independently may assess the primary presentation of this rare malignancy. Clinically relevant perspectives on expectations of PCNSL manifestation in both ocular and non-ocular CNS compartments would help inform management practices in each specialty, which should impact clinical outcomes. A recent increase in the number of published PCNSL cohort studies provides new opportunity to review the current prevalence rates of ocular involvement, and the timing of this involvement over the course of disease. In PCNSL cohorts defined by non-ocular CNS compartment involvement, with or without ocular involvement (termed "PCNSL ± ocular involvement" cohorts), mean rates of concomitant VRL at diagnosis, or at any time during the course, are 10% and 16%, respectively. Only a few individuals within this cohort group present with exclusive eye disease (<5%), and the rate of secondary ocular involvement is only 5-9%. In PCNSL cohorts defined by the involvement of the ocular compartment, with or without non-ocular CNS involvement (termed "VRL ± non-ocular CNS involvement" cohorts), 58% of persons have a primary ocular diagnosis, which carries a 50% risk of secondary involvement in the CNS beyond the eye. Rates of non-ocular CNS involvement with VRL at diagnosis or over the course of disease are 41% and 69%, respectively.

Impact of maintenance rituximab on duration of response in primary central nervous system lymphoma

PURPOSE

The role of maintenance immunotherapy with anti-CD20 monoclonal antibody rituximab in primary central nervous system lymphoma (PCNSL) is unclear. We retrospectively reviewed the medical records of all immunocompetent adults with newly diagnosed PCNSL treated at our institution between1996 and 2017.

METHODS

We identified 66 patients who attained complete response (CR) after completion of first-line regimen; 20 received maintenance therapy (maintenance therapy group) and 46 were observed with serial MRI scans without maintenance therapy (no-maintenance therapy group).

RESULTS

Compared to the surveillance group, there was a significant increase in duration of survival (HR 0.27, 95% CI 0.08-0.98, P = 0.046) in the maintenance therapy group while the reduction in the risk of progression was not significant (HR: 0.61, 95% CI 0.26-1.43, P = 0.259).

CONCLUSION

We are evaluating the effectiveness of maintenance immunotherapy in PCNSL in a prospective multicenter randomized clinical trial.

Induction therapy with the MATRix regimen in patients with newly diagnosed primary diffuse large B-cell lymphoma of the central nervous system - an international study of feasibility and efficacy in routine clinical practice

The MATRix chemoimmunotherapy regimen is highly effective in patients with newly diagnosed primary diffuse large B-cell lymphoma of the central nervous system (PCNSL). However, nothing is known about its feasibility and efficacy in everyday practice, where patients are more often older/frailer than those enrolled in clinical trials. We conducted a retrospective study addressing tolerability/efficacy of MATRix in 156 consecutive patients with newly diagnosed PCNSL treated outside a clinical trial. Median age and ECOG Performance Status of considered patients were 62 years (range 28-78) and 2 (range 0-4). The overall response rate after MATRix was 79%. Nine (6%) treatment-related deaths were recorded. After a median follow-up of 27.4 months (95% confidence interval [CI] 24.4-31.9%), the two-year progression-free and overall survival were 56% (95% CI 48.4-64.9%) and 64.1% (95% CI 56.7-72.5%) respectively. Patients not eligible for the IELSG32 trial were treated with lower dose intensity and had substantially worse outcomes than those fulfilling inclusion criteria. This is the largest series of PCNSL patients treated with MATRix outside a trial and recapitulates the IELSG32 trial outcomes in the non-trial setting for patients who fit the trial criteria. These data underscore the feasibility and efficacy of MATRix as induction treatment for fit patients in routine practice.

Curative effect of methotrexate combined with teniposide in the treatment of primary central nervous system lymphoma

The present study aimed to investigate the curative effect of high-dose methotrexate (HD-MTX) combined with teniposide (Vm26) vs. HD-MTX alone in the treatment of primary central nervous system lymphoma (PCNSL), in order to provide data for assisting decisions associated with clinical treatment. Data from 56 patients with PCNSL admitted in Shanghai Huashan Hospital (Shanghai, China) from January 2009 to December 2014 were included into the present study. Clinical data, curative effects and prognosis of patients in these two groups were retrospectively analyzed using SPSS 20 statistical software. In the HD-MTX+Vm26 group, 12 patients (42.85%) achieved complete remission (CR) and 10 patients (35.71%) achieved partial remission (PR), while in the HD-MTX group 7 patients (25%) achieved CR and 11 patients (39.29%) achieved PR (P=0.158). The median progression-free survival (PFS) time was 22 months in the HD-MTX+Vm26 group and 12 months in the HD-MTX group (P=0.019). The median overall survival time was 57 months in the HD-MTX+Vm26 group, and 28 months in the HD-MTX group (P=0.013). Compared with HD-MTX alone, the combined treatment of HD-MTX+Vm26 had an improved curative effect in the treatment of PCNSL, effectively controlled tumor progression in patients, prolonged survival time and improved prognosis. Age was an independent prognostic factor in patients with PCNSL. Patients with an age of ≤60 years exhibited longer PFS compared with patients with an age of >60 years.

Management and outcome of primary CNS lymphoma in the modern era: An LOC network study

OBJECTIVE

Real-life studies on patients with primary CNS lymphoma (PCNSL) are scarce. Our objective was to analyze, in a nationwide population-based study, the current medical practice in the management of PCNSL.

METHODS

The French oculo-cerebral lymphoma network (LOC) database prospectively records all newly diagnosed PCNSL cases from 32 French centers. Data of patients diagnosed between 2011 and 2016 were retrospectively analyzed.

RESULTS

We identified 1,002 immunocompetent patients (43% aged >70 years, median Karnofsky Performance Status [KPS] 60). First-line treatment was high-dose methotrexate-based chemotherapy in 92% of cases, with an increasing use of rituximab over time (66%). Patients <60 years of age received consolidation treatment in 77% of cases, consisting of whole-brain radiotherapy (WBRT) (54%) or high-dose chemotherapy with autologous stem cell transplantation (HCT-ASCT) (23%). Among patients >60 years of age, WBRT and HCT-ASCT consolidation were administered in only 9% and 2%, respectively. The complete response rate to initial chemotherapy was 50%. Median progression-free survival was 10.5 months. For relapse, second-line chemotherapy, HCT-ASCT, WBRT, and palliative care were offered to 55%, 17%, 10%, and 18% of patients, respectively. The median, 2-year, and 5-year overall survival was 25.3 months, 51%, and 38%, respectively (<60 years: not reached [NR], 70%, and 61%; >60 years: 15.4 months, 44%, and 28%). Age, KPS, sex, and response to induction CT were independent prognostic factors in multivariate analysis.

CONCLUSIONS

Our study confirms the increasing proportion of elderly within the PCNSL population and shows comparable outcome in this population-based study with those reported by clinical trials, reflecting a notable application of recent PCNSL advances in treatment.

High Detection Rate of MYD88 Mutations in Cerebrospinal Fluid From Patients With CNS Lymphomas

PURPOSE

Biopsy is the gold standard for the diagnosis of primary CNS lymphoma (PCNSL). However, surgical biopsy has problems of morbidity related to hemorrhagic complications and false-negative findings, so safer and more reliable diagnostic methods are required. The aim of this study is to detect the MYD88 mutation, an important driver mutation, in the cerebrospinal fluid (CSF) of patients with CNS lymphoma.

PATIENTS AND METHODS

Twenty-six patients with CNS lymphoma (20 primary CNS lymphoma and six CNS relapse from systemic lymphoma) were studied. We extracted cell-free DNA (cfDNA) from CSF by lumbar puncture. cfDNA was extracted from 1 mL of CSF, and Sanger sequencing and droplet digital polymerase chain reaction (ddPCR) were performed. Furthermore, we performed DNA sequencing of MYD88 in 21 cases with available surgically obtained formalin-fixed paraffin-embedded (FFPE) tissue and compared the results.

RESULTS

The median cfDNA amount extracted from 1 mL CSF was 219 ng/mL (25th to 75th percentile, 129 to 333 ng/mL). MYD88 mutations were detected from CSF in 76.9% (20 of 26 cases), and L265P in exon 5 was the most frequent mutation in 19 out of 20 (95.0%) cases. S219C in exon 3 was detected in one case. In four patients, MYD88 mutation was confirmed by ddPCR but not by Sanger sequencing. In all 21 cases with sufficient FFPE tissue for DNA analysis, the detection of MYD88 mutation from cfDNA was consistent with those of tumor-derived DNA from FFPE tissue.

CONCLUSION

This pilot study provided evidence that the somatic driver mutation MYD88 can be reliably detected by combination of Sanger sequencing and ddPCR in the cfDNA taken from 1 mL of CSF in patients with CNS lymphomas.

Utility of flouro-deoxy-glucose positron emission tomography/computed tomography in the diagnostic and staging evaluation of patients with primary CNS lymphoma

Aim: To prospectively assess the clinical utility of pretreatment flouro-deoxy-glucose positron emission tomography/computed tomography (18F-FDG-PET/CT) in patients with primary central nervous system (CNS) lymphoma (PCNSL). Materials & methods: Patients with suspected/proven PCNSL underwent baseline whole-body 18F-FDG-PET/CT. Maximum standardized uptake value and tumor/normal tissue ratios were compared between CNS lymphoma and other histological diagnoses. Results: The mean maximum standardized uptake value (27.5 vs 18.2; p = 0.001) and mean tumor/normal tissue ratio (2.34 vs 1.53; p < 0.001) of CNS lymphoma was significantly higher than other histologic diagnoses. Five of 50 (10%) patients with biopsy-proven CNS lymphomas had pathologically increased FDG-uptake at extraneuraxial sites uncovering systemic lymphoma. Conclusion: Pretreatment whole-body 18F-FDG-PET/CT provides valuable complementary information in the diagnostic and staging evaluation of patients with PCNSL to guide therapeutic decision-making.

Parenchymal central nervous system involvement in aggressive B-cell lymphoma: retrospective analysis of clinical and MRI features in a Chinese population

BACKGROUND

Secondary central nervous system lymphoma (SCNSL) is defined as secondary central nervous system (CNS) involvement in patients with systemic lymphoma. It is considered a profoundly adverse complication with inferior clinical outcome. Parenchymal involvement in the CNS in aggressive B-cell lymphoma is not frequently seen and remains a diagnostic dilemma.

METHODS

In our study, we retrospectively analyzed the clinical and magnetic resonance imaging (MRI) features of 26 parenchymal SCNSL patients. In addition, we compared MRI features of SCNSL and primary CNS lymphoma (PCNSL) patients after 1:1 propensity score matching. Also we presented two SCNSL cases with atypical MRI appearance.

RESULTS

Among SCNSL patients, the median CNS relapse time was 3 months, and multiple lesions were found in 76.9% of the cases. In PCNSL, this percentage was 42.3% (p = 0.011). None of the SCNSL patients and 23.1% of the PCNSL patients had solitary infratentorial lesions (p = 0.003).

CONCLUSIONS

The majority of parenchymal involvement occurred within the first year of systemic lymphoma, in which mostly cases presenting with multiple and supratentorial locations, unlike what was found in PCNSL.

Tumor and Cerebrospinal Fluid microRNAs in Primary Central Nervous System Lymphomas

Primary central nervous system lymphoma (PCNSL) is a rare, highly aggressive, extranodal form of non-Hodgkin lymphoma, predominantly diagnosed as primary diffuse large B-cell lymphoma of the central nervous system (CNS DLBCL). Fast and precise diagnosis of PCNSL is critical yet challenging. microRNAs, important regulators in physiology and pathology are potential biomarkers. In 131 patients with CNS DLBCL and with non-malignant brain lesions (n-ML), miR-21, miR-19b and miR-92a, miR-155, miR-196b, miR-let-7b, miR-125b, and miR-9 were examined by RT-qPCR in brain biopsy samples (formalin-fixed paraffin-embedded tissues, FFPET; CNS DLBCL, n = 52; n-ML, n = 42) and cerebrospinal fluid samples (CSF; CNS DLBCL, n = 30; n-ML, n = 23) taken for routine diagnosis. FFPET samples were split into study and validation sets. Significantly higher CSF levels of miR-21, miR-19b, and miR-92a were identified in PCNSL but not in n-ML, and differentiated PCNSL from n-ML with 63.33% sensitivity and 80.77% specificity. In FFPETs, miR-155 and miR-196b were significantly overexpressed and miR-let-7b, miR-125b, and miR-9 were downregulated in PCNSL as compared to n-ML. Combined miR-155 and miR-let-7b expression levels in FFPETs discriminated PCNSL and n-ML with a 97% accuracy. In conclusion, tissue miR-155, miR-196b, miR-9, miR-125b, and miR-let-7b expression profiles differentiate PCNSL from n-ML. PCNSL CSFs and the relevant biopsy samples are characterized by specific, different microRNA profiles. A logistic regression model is proposed to discriminate between PCNSL and non-malignant brain lesions. None of the examined microRNAs influenced overall survival of PCNSL patients. Further ongoing developments involve next generation sequencing-based profiling of biopsy and CSF samples.

Rituximab in primary central nervous system lymphoma-A systematic review and meta-analysis

The CD-20 antibody rituximab is a standard component of treatment of non-Hodgkin B-cell lymphomas, including diffuse large B-cell lymphoma (DLBCL). Primary DLBCL of the central nervous system, also called primary central nervous system lymphoma (PCNSL), is a DLBCL confined to the central nervous system. There has been debate whether intravenous rituximab accumulates sufficiently in the central nervous system to exert an effect. In this systematic review, we assess the benefits and harms of rituximab in the treatment of immunocompetent patients with PCNSL. By searching MEDLINE, CENTRAL, and ClincialTrials.gov up to March 2019, we identified randomized controlled trials (RCTs) investigating the effect of rituximab in patients with PCNSL. We extracted study characteristics and results, assessed risk of bias, performed trial-level random-effects meta-analyses, and graded the certainty of evidence. The protocol was registered with PROSPERO (CRD42019121965). Main outcomes were overall survival (time to death), progression-free survival (time to progression or death), quality of life, grades 3 and 4 toxicity, and treatment-related mortality. We included two RCTs with a total of 343 participants. Overall survival was not statistically significantly improved (HR 0.76; 95% CI, 0.52-1.12; low certainty), with 187 fewer to 39 more deaths after 2 years in 1000 treated patients. Low certainty of evidence indicated that rituximab improved progression-free survival (HR 0.65; 95% CI, 0.45-0.95), which translated into 137 fewer progressions or deaths after 2 years in 1000 treated patients (231 to 18 fewer). None of the RCTs provided data on quality of life. We found no evidence that rituximab increased grades 3 and 4 toxicity or treatment-related mortality (RR 0.53; 95% CI, 0.20-1.37; low certainty). Overall, the available evidence suggests with low certainty that rituximab in combination with methotrexate-based chemotherapy may improve progression-free survival in immunocompetent patients with newly diagnosed PCNSL, the pooled effect estimates did not show evidence for improvement of overall survival.