Is whole-brain irradiation necessary for primary central nervous system lymphoma? Patterns of recurrence after partial-brain irradiation

Patterns of Treatment Failure in Primary Central Nervous System Lymphoma

OBJECTIVES

Progression of PCNSL remains a challenge with salvage therapies, including the risk of substantial morbidity and mortality. We report patterns of first tumor progression to inform opportunities for improvement.

METHODS

This is an institutional retrospective review from 2002 to 2021 of 95 consecutive patients with pathologically confirmed PCNSL, of whom 29 experienced progressive disease. Kaplan-Meier method, log-rank test, and Cox proportional hazard models are used to characterize associations of patient, tumor, and treatment variables with LC, PFS, and patterns of first failure.

RESULTS

Most patients were below 65 years old (62%) with KPS >70 (64%) and negative CSF cytology (70%). In 70 patients with MRIs, the median tumor volume was 12.6 mL (range: 0.5 to 67.8 mL). After a median follow-up of 11 months, 1-year PFS was 48% and 1-year LC was 80%. Of the 29 patients with progression, 24% were distant only, 17% were distant and local, and 59% were local only. On MVA, LC was associated with age (HR: 1.08/y, P =0.02), KPS (HR: 0.10, P =0.02), completion of >6 cycles of HD-MTX (HR: 0.10, P <0.01), and use of intrathecal chemotherapy (HR: 0.03, P <0.01). On UVA, local only first failure trended to be increased with >14 mL tumors (OR: 5.06, P =0.08) with 1-year LC 83% (<14 mL) versus 64% (>14mL). There were no significant associations with LC and WBRT ( P =0.37), Rituximab ( P =0.12), or attempted gross total resection ( P =0.72).

CONCLUSIONS

Our findings reaffirm the importance of systemic and intrathecal therapies for local control in PCNSL. However, bulky tumors trend to fail locally, warranting further investigation about the role of local therapies or systemic therapy intensification.

Primary central nervous system lymphomas: EHA-ESMO Clinical Practice Guideline for diagnosis, treatment and follow-up

This EHA-ESMO Clinical Practice Guideline provides key recommendations for managing primary DLBCL of the CNS.The guideline covers clinical, imaging and pathological diagnosis, staging and risk assessment, treatment and follow-up.Algorithms for first-line and salvage treatments are provided.The author group encompasses a multidisciplinary group of experts from different institutions and countries in Europe.Recommendations are based on available scientific data and the authors' collective expert opinion.

A disease warranting attention from neurosurgeons: primary central nervous system post-transplant lymphoproliferative disorder

Background

Primary central nervous system post-transplant lymphoproliferative disorder (PCNS-PTLD) is a rare condition, posing diagnostic and treatment challenges, with histological biopsy essential for diagnosis. Standardized treatment protocols are lacking. This disease requires urgent attention due to the increasing number of organ transplant surgeries and the use of immunosuppressive agents.

Methods

From 2020 to 2023, our center diagnosed five patients with PCNS-PTLD. We reviewed their clinical records and conducted a comprehensive analysis of 22 literatures on PCNS-PTLD cases following renal transplantation or allogeneic hematopoietic stem cell transplantation (HSCT).

Results

Four patients had previously received a kidney transplant, one had undergone allogeneic HSCT. The median time from the last transplant surgery to the diagnosis of PCNS-PTLD differs between kidney transplant (21.5 years) and allogeneic HSCT (9 months). Common symptoms included motor weakness (n = 4), headache (n = 2), confusion (n = 2), and nausea (n = 2), with ring-enhancing (n = 5), typically solitary (n = 3) and supratentorial (n = 3) lesions on imaging. Diagnosis involved robot-assisted stereotactic brain biopsy (n = 4) or craniotomy (n = 1), all showing Epstein-Barr virus and CD20 positivity. Most cases (n = 4) were monomorphic diffuse large B-cell lymphoma. Treatment included rituximab (n = 3), surgical resection (n = 2), zanubrutinib (n = 1), whole-brain radiation (n = 1), and methotrexate (n = 1). At the last follow-up, the median duration of follow-up for all patients was 19 months. During this time, 3 patients had died and 2 patients were still alive.

Conclusion

In patients with a history of kidney transplantation or allogeneic HSCT who are on long-term immunosuppressive therapy, any neurological symptoms, particularly the presence of supratentorial ring-enhancing masses in the brain on imaging, whether solitary or multiple, should raise high suspicion for this disease, warranting a timely brain biopsy. Additionally, we found that besides reducing immunosuppressants, zanubrutinib may be a potential, safe, and effective treatment for this condition. Moreover, post-surgical administration of rituximab in conjunction with whole-brain radiotherapy also appears to be a potentially safe and effective approach.

Is reduced-dose whole-brain radiotherapy also feasible in primary CNS lymphoma for curative or salvage purpose?

PURPOSE

Recently, reduced-dose whole-brain radiotherapy (WBRT) has been used to treat primary central nervous system lymphoma (PCNSL). However, whether reduced-dose WBRT is also an acceptable option for curative or salvage purposes has not yet been reported. We analyzed the clinical outcomes of patients with PCNSL who received radiotherapy for curative or salvage purposes and compared the clinical outcomes according to the WBRT dose.

METHODS

A total of 66 patients were divided into two groups: those treated with 30 Gy (2 Gy per fraction) or less WBRT (low-dose WBRT, n = 34) and those treated with more than 30 Gy WBRT (high-dose WBRT, n = 32). The median WBRT dose was 25.2 and 49.6 Gy in low-dose and high-dose WBRT groups, respectively. The median total radiotherapy dose, including the boost dose, was 50 Gy (range, 36.0-55.8 Gy).

RESULTS

The 3-year overall survival and progression-free survival were 77.8% and 29.8%, respectively. Intracranial relapse occurred in 31 patients (47.0%) at a median of 27 months after RT. Overall survival and progression-free survival did not differ between the two groups. The 3-year intracranial disease control rate did not differ between the two groups (35.2% vs. 41.6%, p = 0.300). Grade 3 or higher neurological toxicities were observed in six patients, of whom five were in the high-dose WBRT group.

CONCLUSION

Reduced-dose WBRT in curative and salvage treatments for PCNSL had no significant negative effect on the intracranial disease control rate or survival. Therefore, without impaired efficacy, use of reduced-dose WBRT appears promising for reduction of neurotoxicity.

May we routinely spare hippocampal region in primary central nervous system lymphoma during whole brain radiotherapy?

PURPOSE

One of the main limiting factors of whole-brain radiation therapy (WBRT) for primary central nervous system lymphoma (PCNSL) is the impairment of neurocognitive functions (NCFs), which is mainly caused by radiation-induced injury to the hippocampus. With a view to preventing NCF impairment and personalizing treatment, we explored the feasibility of sparing the hippocampus during WBRT by correlating the sites of PCNSL lesions with the hippocampus.

METHODS AND MATERIALS

Pre-treatment MR images from patients who underwent WBRT between 2010 and January 2020-and post-radiotherapy images in cases of relapse-were imported into the Varian Eclipse treatment-planning system and registered with the simulation CT. We constructed three 3-dimensional envelopes around the hippocampus at distances of 5, 10 and 15 mm and also contoured primary lesions and recurrences.

RESULTS

We analyzed 43 patients with 66 primary lesions: 9/66 (13.6%) involved the hippocampus and 11/66 (16.7%) were located within 5 mm of it. Thirty-six lesions (54.5%) were situated more than 15 mm from the hippocampus, while 10/66 (15.2%) were between 5 and 15 mm from it. The most common location was in deep brain structures (31%). Thirty-five of the 66 lesions relapsed: in field in 14/35 (40%) and outfield in 21/35 (60%) in different sites. Globally, 16/35 recurrences (45.7%) were located in the hippocampus or within 5 mm of it.

CONCLUSION

These data show that routinely sparing the hippocampus is not feasible. This approach could be considered in selected patients, when the lesion is more than 15 mm from the hippocampus.

Fractionated Stereotactic Radiation for Central Nervous System Lymphoma: Retrospective Analysis of Initial Cases

Primary central nervous system lymphoma (PCNSL) is primarily treated with combination chemotherapy, while whole-brain radiotherapy (WBRT) can be used as consolidative treatment or as a salvage option for central nervous system (CNS) relapse. We investigated whether fractionated stereotactic radiosurgery (fSRS) could replace WBRT in cases where patients had poor performance status or minimal disease at the time of consolidation, to spare patients the adverse effects of WBRT. We retrospectively identified 10 patients who completed 14 courses of fSRS for PCNSL or for CNS relapse of systemic lymphoma. Of 14 fSRS treatments, there were 10 distant brain recurrences among 6 patients, occurring on average 13.6 months after fSRS. A total of 4 of the 10 recurrences were treated with further fSRS, and 4 were treated with WBRT. There was one late in-field recurrence after both fSRS and WBRT, which occurred 27 months after fSRS. The median survival after fSRS was 36 months, and side effects after fSRS were minimal. This case series represents a potential treatment option for patients with CNS lymphoma, for whom WBRT is indicated but where the toxic effects of this treatment would be prohibitive.

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.

Safety and efficacy of tisagenlecleucel in primary CNS lymphoma: a phase 1/2 clinical trial

CD19-directed chimerical antigen receptor T-cell (CAR-T) products have gained US Food and Drug Administration approval for systemic large B-cell lymphoma. Because of concerns about potential immune cell-associated neurotoxicity syndrome (ICANS), patients with primary central nervous system (CNS) lymphoma (PCNSL) were excluded from all pivotal CAR-T studies. We conducted a phase 1/2 clinical trial of tisagenlecleucel in a highly refractory patients with PCNSL and significant unmet medical need. Here, we present results of 12 relapsed patients with PCNSL who were treated with tisagenlecleucel and followed for a median time of 12.2 months (range, 3.64-23.5). Grade 1 cytokine release syndrome was observed in 7/12 patients (58.3%), low-grade ICANS in 5/12 (41.6%) patients, and only 1 patient experienced grade 3 ICANS. Seven of 12 patients (58.3%) demonstrated response, including a complete response in 6/12 patients (50%). There were no treatment-related deaths. Three patients had ongoing complete remission at data cutoff. Tisagenlecleucel expanded in the peripheral blood and trafficked to the CNS. Exploratory analysis identified T-cell, CAR T, and macrophage gene signatures in cerebrospinal fluid following infusion when compared with baseline. Overall, tisagenlecleucel was well tolerated and resulted in a sustained remission in 3/7 (42.9%) of initial responders. These data suggest that tisagenlecleucel is safe and effective in this highly refractory patient population. This trial was registered at www.clinicaltrials.gov as #NCT02445248.

Revisiting the concept of recurrence of primary CNS lymphomas after complete response to methotrexate-based therapy: Periventricular reseeding as the predominant mechanism of recurrence

Purpose

Understanding patterns of relapse for primary central nervous system lymphoma (PCNSL) may inform mechanisms of recurrence and optimal consolidation strategies. In this study, we report patterns of relapse among patients with PCNSL who achieved a complete response to high-dose methotrexate (HD-MTX)-based chemotherapy with or without consolidation radiation therapy (RT).

Methods and Materials

We conducted an institutional retrospective analysis of patients with PCNSL who received HD-MTX-based chemotherapy between November 2001 and May 2019. Relapses were characterized as in-field (within original T1 contrasted lesion), marginal (within T2 fluid-attenuated inversion recovery but not T1), local (in-field or marginal), distant brain (no overlap), or distant (distant brain, cerebrospinal fluid, vitreous or extra-axial) and further characterized with respect to periventricular location (≤10 mm of ventricles).

Results

Seventy-eight patients with PCNSL met inclusion criteria, of whom 29 (37%) underwent consolidation RT. Median progression-free survival and overall survival were 57.0 and 66.7 months, respectively. After a median follow-up of 38.9 months, a total of 32 patients (41%) experienced recurrence. Most patients (21 [65.6%]) had a periventricular failure. Surprisingly, local recurrences (n = 11) were exclusively observed within periventricular lesions, whereas distant recurrences (n = 21) were seen in both periventricular and nonperiventricular locations (P = .009). The median time to progression was shorter for locally recurrent lesions compared with distant recurrences (13.8 vs 26.1 months; P = .03).

Conclusions

After complete response to HD-MTX, few failures occurred within initial T1 contrast-enhancing lesions and many of these may have been alternatively classified as periventricular failures. These observations argue against the use of purely focal RT consolidation for patients who achieve a complete response after HD-MTX-based chemotherapy and suggest that periventricular reseeding may have a central role in PCNSL recurrence.

A narrative review of consolidation strategies for young and fit patients with newly-diagnosed primary central nervous system lymphoma

INTRODUCTION

The modern treatment of patients with primary central nervous system lymphoma (PCNSL) consists of two phases: induction, currently represented by a high-dose-methotrexate-based polychemotherapy, and consolidation. The optimal consolidation therapy has not been defined yet, but several strategies, such as whole-brain radiotherapy (WBRT), high-dose chemotherapy supported by autologous stem cell transplantation (HDC/ASCT) or non-myeloablative chemotherapy, have been addressed in important randomized trials.

AREAS COVERED

This review provides an overview of the current role of consolidation strategies in young and fit patients with newly-diagnosed PCNSL. Publications in English language, peer-reviewed, from high-quality international journals, edited from 2003 to 2021 were identified on PubMed.

EXPERT OPINION

Consolidation treatment significantly improved outcomes of PCNSL. Radiotherapy had represented for years the only choice in the consolidation therapy, but large randomized trials have demonstrated that HDC/ASCT is equally effective and associated with lower neurotoxicity risk in patients younger than 65-70 years. Encouraging results have been obtained using reduced-dose WBRT, while a recent randomized trial failed to demonstrate that consolidation with non-myeloablative chemotherapy is more effective than HDC/ASCT in PCNSL patients. A personalized consolidation treatment, driven also by a response prediction model based on radiological and molecular details, may improve the management of PCNSL patients.

Selective salvage radiotherapy could provide favorable outcomes in patients with refractory or relapsed primary central nervous system lymphoma

INTRODUCTION

To date, there is no relevant data supporting the role of salvage radiotherapy (sRT) in patients with refractory or relapsed primary central nervous system lymphoma (PCNSL). Herein, we aimed to investigate the impact of sRT in patients with refractory or relapsed PCNSL following upfront HD-MTX.

METHODS

We retrospectively reviewed 89 patients who had refractory (n = 16) or recurrent disease after an initial favorable response (n = 73); among them, 41 were treated with sRT and 48 were treated without sRT (nRT). Event-free survival (rEFS) and overall survival (rOS) after first recurrence were considered from the date of recurrence to date of each event.

RESULTS

Overall, the first failure was diagnosed at a median of 11.0 months [interquartile range (IQR), 5.6-26.4] after first treatment. More than half of the patients had recurrent disease involving initial tumor bed (n = 47), deep structure (n = 67), and multiple lesions (n = 58). Among 19 patients who were initially treated with 23.4 Gy of whole brain RT, 10 patients received sRT as a re-irradiation; other 31 patients in sRT group were RT naïve patients. There was no significant difference in tumor characteristics between sRT and nRT group. Overall and complete response after salvage treatment were 80% and 48%, respectively; sRT provided higher overall response rate than nRT (93% vs. 69%, p = 0.011). With a median follow-up of 14.3 months (IQR, 7.9-31.4), 2-year rEFS and rOS rates were 27% and 57%, respectively. There were no differences in rEFS and rOS according to sRT (sRT vs. nRT, 26% vs. 28%, p = 0.730; 63% vs. 50%, p = 0.690). Poor performance, recurrence interval < 8 months, and unfavorable response following salvage treatment were associated with inferior rEFS and rOS. Additionally, sRT and stem cell transplantation improved response rate independently after multivariate analysis for complete/partial response.

CONCLUSIONS

We found favorable response rate and comparable survival outcomes following sRT compared with non-local treatments for patients with refractory/relapsed PCNSL. Further studies of patient selection could stratify patients who can benefit from sRT.

Central Nervous System Lymphoma: Approach to Diagnosis and Treatment

Central nervous system lymphoma (CNSL) is a rare form of extranodal non-Hodgkin lymphoma. Central nervous system lymphoma can be primary (isolated to the central nervous space) or secondary in the setting of systemic disease. Treatment of CNSL has improved since the introduction of high-dose methotrexate and aggressive consolidation regimens. However, results after treatment are durable in only half of patients, and long-term survivors may experience late neurotoxicity, impacting quality of life. Given the rarity of this disease, few randomized prospective trials exist. This leaves many questions unanswered regarding optimal first-line and salvage treatments. Recent advances in the knowledge of pathophysiology of CNSL will hopefully help the development of future treatments. This review gives an overview of the epidemiology, pathophysiology, clinical presentation, diagnosis, and treatment of immunocompetent patients with CNSL.

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.

Advances and challenges in the treatment of primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL), a rare variant of non-Hodgkin's lymphoma, is characterized by distinct biological characteristics and clinical behaviors, and patient prognosis is not satisfactory. The advent of high-dose (HD) methotrexate (HD-MTX) therapy has significantly improved PCNSL prognosis. Currently, HD-MTX-based chemotherapy regimens are recognized as first-line treatment. PCNSL is sensitive to radiotherapy, and whole-brain radiotherapy (WBRT) can consolidate response to chemotherapy; however, WBRT-associated delayed neurotoxicity leads to neurocognitive impairment, especially in elderly patients. Other effective approaches include rituximab, temozolomide, and autologous stem-cell transplantation (ASCT). In addition, new drugs against PCNSL such as those targeting the B-cell receptor signaling pathway, are undergoing clinical trials. However, optimal therapeutic approaches in PCNSL remain undefined. This review provides an overview of advances in surgical approaches, induction chemotherapy, radiotherapy, ASCT, salvage treatments, and novel therapeutic approaches in immunocompetent patients with PCNSL in the past 5 years. Additionally, therapeutic progress in elderly patients and in those with relapsed/refractory PCNSL is also summarized based on the outcomes of recent clinical studies.

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.

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.

Is whole-brain radiotherapy still a standard treatment for primary central nervous system lymphomas?

PURPOSE OF REVIEW

In primary central nervous system lymphomas (PCNSL), optimal therapy remains to be established, and the role of whole-brain radiotherapy (WBRT) is a matter of debate. With radiation alone, transient responses and clinical improvement are frequent, but long-term disease control is exceptional. WBRT has been considered possible consolidation therapy after high-dose methotrexate (HDMTX)-based initial chemotherapy. This strategy has been questioned due to a high risk of delayed neurotoxicity after combined treatment. This review analyses the current role of WBRT in PCNSL.

RECENT FINDINGS

Neither in retrospective analyses nor in randomized trials, an overall survival benefit with WBRT in addition to HDMTX-based initial chemotherapy could be found. On the other hand, a recent randomized trial did not show superiority of consolidation with high-dose chemotherapy followed by autologous stem-cell transplantation to consolidation WBRT after initial HDMTX-based polychemotherapy. This finding, however, is probably due to an intense initial therapy and to a small number of patients having reached consolidation and randomization to WBRT vs. high-dose chemotherapy followed by autologous stem-cell transplantation.

SUMMARY

The current role of WBRT in PCNSL is confined to patients who cannot tolerate chemotherapy or have failed it. WBRT should not routinely be used for consolidation of HDMTX-based chemotherapy due to lack of evidence of efficacy as additional treatment and due to a high risk of neurotoxicity.

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.

Response-adapted radiation therapy for newly diagnosed primary diffuse large B-cell lymphoma of the CNS treated with methotrexate-based systemic therapy

Background

For patients with primary diffuse large B-cell lymphoma of the central nervous system (PCNSL), whole-brain radiation therapy (WBRT) to doses of ≥45 Gy are often given after a partial response (PR) to methotrexate-based induction chemotherapy. We conducted an exploratory analysis to determine whether lower-dose WBRT, given with a boost to sites of persistent disease, might be a reasonable alternative.

Methods and materials

We retrospectively reviewed the records of 22 patients with PCNSL who received WBRT, with or without a boost, after methotrexate-based induction chemotherapy. Outcomes were compared among patients according to response to chemotherapy using the Kaplan-Meier method.

Results

Median follow-up was 52 months. All patients with a complete response (CR) (n = 5) received WBRT to 23.4 Gy. One CR patient died after an in-field relapse. Patients with partial response (PR) (n = 10) received a median whole-brain dose of 23.4 Gy with (n = 8) or without (n = 2) a boost; there were 2 relapses within the central nervous system (CNS). All PR patients were alive at the time of analysis. The overall survival (P = .127) and freedom from relapse within the CNS (P = .967) were not different for patients with CR versus PR. Baseline and follow-up neurocognitive evaluations were available for 4 PR patients, and there were no significant differences between pre- and post-treatment evaluations (P > .05 for language, memory, visual-spatial, attention, or motor functions). All patients who progressed or did not respond to chemotherapy and then received WBRT had died at a median time of 3.4 months. Patients who progressed or did not respond to chemotherapy had worse overall survival (P = .001) and freedom from CNS relapse (P = .005) compared with CR patients.

Conclusions

Among patients with a PR to induction chemotherapy, reduced-dose WBRT with a boost to residual PCNSL may be a viable treatment approach that merits further investigation.

Treatment of Primary Central Nervous System Lymphoma: From Chemotherapy to Small Molecules

Primary central nervous system lymphoma (PCNSL) is a rare form of extranodal non-Hodgkin lymphoma that is typically confined to the brain, eyes, and cerebrospinal fluid (CSF) without evidence of systemic spread. PCNSL is an uncommon tumor, and only four randomized trials and one phase III trial have been completed so far, all in the first-line setting. The prognosis of patients with PCNSL has improved during the past few decades with the introduction of high-dose methotrexate (HD-MTX), which now serves as the backbone of all first-line treatment regimens. Despite recent progress, results after treatment are durable in half of patients, and therapy can be associated with late neurotoxicity. Novel insights into the pathophysiology of PCNSL have identified the B-cell receptor (BCR) pathway as a key mechanism in the pathogenesis of PCNSL. The use of novel agents targeting components of the BCR pathway, namely the Bruton tyrosine kinase (BTK) inhibitor ibrutinib, and immunomodulatory drugs (IMIDs) like lenalidomide and pomalidomide, has so far been limited to patients who have recurrent/refractory PCNSL with promising high response rates. Within the past 5 years, there has been a peak in clinical trials investigating small molecules and novel reagents in the recurrent/refractory setting, including immune checkpoint inhibitors, IMIDs, and BTK and PI3K/AKT/mTOR inhibitors.

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.

Primary CNS Lymphoma

Primary CNS lymphoma (PCNSL) is a rare form of extranodal non-Hodgkin lymphoma that is typically confined to the brain, eyes, and cerebrospinal fluid without evidence of systemic spread. The prognosis of patients with PCNSL has improved during the last decades with the introduction of high-dose methotrexate. However, despite recent progress, results after treatment are durable in half of patients, and therapy can be associated with late neurotoxicity. PCNSL is an uncommon tumor, and only four randomized trials and one phase III trial have been completed so far, all in the first-line setting. To our knowledge, no randomized trial has been conducted for recurrent/refractory disease, leaving many questions unanswered about optimal first-line and salvage treatments. This review will give an overview of the presentation, evaluation, and treatment of immunocompetent patients with PCNSL.

Radiation therapy for older patients with brain tumors

The incidence of brain tumors in the elderly population has increased over the last few decades. Current treatment includes surgery, radiotherapy and chemotherapy, but the optimal management of older patients with brain tumors remains a matter of debate, since aggressive radiation treatments in this population may be associated with high risks of neurological toxicity and deterioration of quality of life. For such patients, a careful clinical status assessment is mandatory both for clinical decision making and for designing randomized trials to adequately evaluate the optimal combination of radiotherapy and chemotherapy.

Several randomized studies have demonstrated the efficacy and safety of chemotherapy for patients with glioblastoma or lymphoma; however, the use of radiotherapy given in association with chemotherapy or as salvage therapy remains an effective treatment option associated with survival benefit. Stereotactic techniques are increasingly used for the treatment of patients with brain metastases and benign tumors, including pituitary adenomas, meningiomas and acoustic neuromas. Although no randomized trials have proven the superiority of SRS over other radiation techniques in older patients with brain metastases or benign brain tumors, data extracted from recent randomized studies and large retrospective series suggest that SRS is an effective approach in such patients associated with survival advantages and toxicity profile similar to those observed in young adults. Future trials need to investigate the optimal radiation techniques and dose/fractionation schedules in older patients with brain tumors with regard to clinical outcomes, neurocognitive function, and quality of life.

[Role of radiotherapy in the treatment of NK/T-cell nasal type and primary cerebral lymphomas]

The head and neck are common sites for extranodal non-Hodgkin lymphomas. Radiotherapy plays an important role in the treatment of low-grade lymphomas, with curative or palliative intent. In the case of high-grade lymphomas, its combination with chemotherapy is debated. Its role is however undeniable in two specific entities: NK/T-cell lymphoma NK/T nasal type, and primary central nervous system lymphomas, which are the subject of this review.

Partial-brain radiotherapy for primary central nervous system lymphoma: multi-institutional experience

Whole-brain radiotherapy (WBRT) has been an important component of treatment for primary central nervous system lymphoma (PCNSL), but delayed neurotoxicity has been a matter of concern. We have employed partial-brain radiotherapy (PBRT) with wide margins for PCNSL patients with a single lesion or a few lesions. In this study, we evaluated the treatment outcome in PCNSL patients undergoing PBRT. Between 2003 and 2014, 24 patients were treated with PBRT; 16 received high-dose-methotrexate (MTX) -containing chemotherapy before PBRT. Conventional fractionation with a median dose of 54 Gy was used. For reference, 15 patients undergoing MTX-based chemotherapy and WBRT were also analyzed. The 3-year overall survival rate was 60% for all 24 patients undergoing PBRT and 68% for the 16 patients undergoing MTX-based chemotherapy plus PBRT. The 3-year progression-free survival rate was 41% for all 24 patients undergoing PBRT and 36% for the 16 patients undergoing MTX-based chemotherapy. The in-field recurrence rate was 26% and the out-of-field recurrence rate was 15% at 3 years for all 24 patients undergoing PBRT. The rates for in-field recurrence and the out-of-field recurrence were 27% and 21%, respectively, for the 16 patients undergoing MTX-based chemotherapy. CNS-recurrence rates were similar in patients undergoing MTX-based chemotherapy and PBRT to the rates in those undergoing MTX-based chemotherapy and WBRT. Neurocognitive dysfunction developed in 3 of the 16 patients undergoing MTX + PBRT and in 4 of 15 patients undergoing MTX + WBRT (P = 0.68). PBRT seems to be a feasible treatment option for solitary PCNSL. Further investigations are warranted to evaluate the advantages of PBRT over WBRT.

Modern radiation therapy for extranodal lymphomas: field and dose guidelines from the International Lymphoma Radiation Oncology Group

Extranodal lymphomas (ENLs) comprise about a third of all non-Hodgkin lymphomas (NHL). Radiation therapy (RT) is frequently used as either primary therapy (particularly for indolent ENL), consolidation after systemic therapy, salvage treatment, or palliation. The wide range of presentations of ENL, involving any organ in the body and the spectrum of histological sub-types, poses a challenge both for routine clinical care and for the conduct of prospective and retrospective studies. This has led to uncertainty and lack of consistency in RT approaches between centers and clinicians. Thus far there is a lack of guidelines for the use of RT in the management of ENL. This report presents an effort by the International Lymphoma Radiation Oncology Group (ILROG) to harmonize and standardize the principles of treatment of ENL, and to address the technical challenges of simulation, volume definition and treatment planning for the most frequently involved organs. Specifically, detailed recommendations for RT volumes are provided. We have applied the same modern principles of involved site radiation therapy as previously developed and published as guidelines for Hodgkin lymphoma and nodal NHL. We have adopted RT volume definitions based on the International Commission on Radiation Units and Measurements (ICRU), as has been widely adopted by the field of radiation oncology for solid tumors. Organ-specific recommendations take into account histological subtype, anatomy, the treatment intent, and other treatment modalities that may be have been used before RT.

[Primary central nervous lymphoma: what is the role for radiotherapy?]

Primary central nervous system lymphoma is a rare extranodal form of non-Hodgkin lymphoma with an aggressive course and unsatisfactory outcome. Historically, whole-brain radiotherapy was the sole treatment for patients with primary central nervous system lymphoma, with high response rates but typically, this did not result in long-lasting remissions. The addition of high-dose methotrexate-based chemotherapy regimens to whole-brain radiotherapy has significantly improved patients' outcome, but has resulted in a higher incidence of late neurotoxicity, particularly in elderly patients. To date, the role of consolidation radiotherapy is controversial, and some investigators have developed alternative strategies aiming at avoiding immediate irradiation or using a reduced radiotherapy dose to the whole-brain with promising results.

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.

Low-dose whole brain radiotherapy with tumor bed boost after methotrexate-based chemotherapy for primary central nervous system lymphoma

PURPOSE

The purpose of this study is to evaluate the outcome of low-dose whole brain radiotherapy (WBRT) with tumor bed boost after methotrexate-based chemotherapy in the management of primary central nervous system lymphoma (PCNSL).

MATERIALS AND METHODS

We retrospectively analyzed 64 patients with pathologically proven PCNSL between 2000 and 2011. Methotrexate-based chemotherapy with a median of five cycles was followed by radiotherapy to the whole brain and to the initial tumor bed. The median dose to the whole brain and to the tumor bed was 27 Gy (range, 18 to 36 Gy) and 50.4 Gy (range, 45 to 54 Gy), respectively.

RESULTS

With a median follow-up period of 27 months, 55 patients (85.9%) achieved complete response (CR). The 5-year overall survival (OS) and progression-free survival (PFS) rates were 52.6% and 39.3%, respectively. In univariate analysis, factors associated with OS were age, performance status, involvement of deep structure, and CR to sequential chemoradiotherapy (CRT). These variables remained as significant factors for OS in multivariate analysis. CR to sequential CRT was the only positive factor associated with PFS (p=0.009). Neurologic toxicity was more common in elderly patients older than 60 years (p=0.025).

CONCLUSION

Low-dose WBRT with tumor bed boost after methotrexate-based chemotherapy might be an effective method for management of PCNSL.

Analysis of radiotherapy in 1054 patients with primary central nervous system lymphoma treated from 1985 to 2009

AIMS

Data on primary central nervous system lymphoma that had been collected through surveys for four consecutive periods between 1985 and 2009 were analysed to evaluate outcomes according to treatment.

MATERIALS AND METHODS

All had histologically proven disease and had received radiotherapy. No patients had AIDS. Among 1054 patients, 696 died and 358 were alive or lost to follow-up. The median follow-up period for surviving patients was 37 months.

RESULTS

For all patients, the median survival time was 24 months; the 5 year survival rate was 25.8%. Patients treated with methotrexate-based chemotherapy and radiation had a higher 5 year survival rate (43%) than those treated with radiation alone (14%) and those treated with non-methotrexate chemotherapy plus radiation (20%), but differences in relapse-free survival were smaller among the three groups. The 5 year survival rate was 25% for patients treated with whole-brain irradiation and 29% for patients treated with partial-brain irradiation (P = 0.80). Patients receiving a total dose of 40-49.9 Gy had a higher 5 year survival rate (32%) than those receiving other doses (21-25%, P = 0.0004) and patients receiving a whole-brain dose of 30-39.9 Gy had a higher 5 year survival rate (32%) than those receiving ≥40 Gy (13-22%, P < 0.0005). Patients receiving methotrexate-based chemotherapy and partial-brain radiotherapy (≥30 Gy) had a 5 year survival rate of 49%.

CONCLUSIONS

The optimal total and whole-brain doses may be in the range of 40-49.9 and <40 Gy, respectively, especially in combination with chemotherapy. Patients receiving partial-brain irradiation had a prognosis similar to that of those receiving whole-brain irradiation. With methotrexate-based chemotherapy, partial-brain radiotherapy may be worth considering for non-elderly patients with a single tumour.

A case series of primary central nervous system posttransplantation lymphoproliferative disorder: imaging and clinical characteristics

BACKGROUND

Primary central nervous system posttransplantation lymphoproliferative disorder (PCNS-PTLD) is a rare complication after solid organ transplantation (SOT). With increasing rates of SOT, PCNS-PTLD incidence is increasing.

OBJECTIVE

To describe the characteristics of PCNS-PTLD patients requiring neurosurgical intervention.

METHODS

From 2000 to 2011, 10 patients with prior SOT underwent biopsy for evaluation of brain lesions and were diagnosed with PCNS-PTLD. Data collected included imaging characteristics, pathology, treatments administered, and survival outcomes.

RESULTS

All patients had kidney transplantation, and 3 had concurrent pancreas transplantation. Median age at diagnosis was 49 years, with a median of 4.5 years from SOT to diagnosis (range, 1.8-11.4 years). Presenting symptoms most often included focal neurological deficits (n = 6), although several patients had nonspecific symptoms of headache and altered mental status. Brain lesions were generally multiple (n = 7), supratentorial (n = 8), and lobar or periventricular in distribution with ring enhancement. Diagnosis was established by stereotactic (n = 4) and open surgical (n = 6) biopsy. Treatments most frequently administered included reduction of immunosuppression (n = 10), dexamethasone (n = 10), rituximab (n = 8), high-dose methotrexate (n = 3), and whole-brain radiotherapy (n = 6). Six patients remain alive without PCNS-PTLD relapse, including 4 patients who have sustained remissions beyond 2 years from diagnosis of PCNS-PTLD. Of 4 observed deaths, 1 was related to progressive PCNS-PTLD.

CONCLUSION

PCNS-PTLD must be considered in the differential diagnosis of any patient with prior SOT presenting with an intracranial lesion. Histological diagnosis with brain biopsy is imperative, given the risk for opportunistic infections that may have similar imaging findings and presentation. Prognosis is variable, although long-term survival has been reported.

Controversies in primary CNS lymphoma

Primary CNS lymphoma is a non-Hodgkin's lymphoma confined to the CNS: the brain, eyes and cerebrospinal fluid. Unlike other primary brain tumors, primary CNS lymphoma is uniquely chemo- and radiosensitive. However, the outcome of primary CNS lymphoma patients is significantly inferior to similar non-Hodgkin's lymphoma patients. Multiple prospective studies using high-dose methotrexate, with or without whole-brain radiotherapy, have reported improved primary CNS lymphoma outcome, but numerous questions remain regarding the optimal care of a given patient.

Primary CNS lymphoma treated with radiotherapy in Japan: a survey of patients treated in 2005-2009 and a comparison with those treated in 1985-2004

BACKGROUND

The aim of our study was to analyze changes over time in the characteristics, treatment, and outcome of patients with primary central nervous system lymphoma (PCNSL).

METHODS

Data on 315 patients with histologically proven PCNSL undergoing radiotherapy between 2005 and 2009 were collected from 20 Japanese institutions using a questionnaire. These data were then compared with data on 273 patients treated during the period 1995-2004 and those on 466 patients treated during the period 1985-1994.

RESULTS

In terms of patient and tumor characteristics, we found a significant increase in mean patient age in the 2005-2009 period compared to the 1985-2004 period (63 vs. 58-59 years, respectively) and in the percentage of patients with better performance status (PS) during the 2005-2009 period compared with the 1995-2004 period (World Health Organization PS 0-2: 73 vs. 65 %, respectively). Regarding treatment, relative to the 1995-2004 period, significant changes in the 2005-2009 period were (1) decreased rate of attempting tumor resection (23 vs. 44 %); (2) increased use of chemotherapy (78 vs. 68 %), and (3) increased use of methotrexate (MTX)-containing regimens (84 vs. 53 %). The 5-year overall survival rates were 15.3, 30.1, and 36.5 % for patients seen during the 1985-1994, 1995-2004, and 2005-2009 periods, respectively, but relapse-free survival did not improve between the 1995-2004 and 2005-2009 periods (26.7 vs. 25.7 % at 5 years, respectively). Patients receiving MTX-containing chemotherapy had 5-year survival rates of 19, 50, and 44 % during these three periods, respectively.

CONCLUSIONS

Although patient backgrounds differed among the study periods, recent trends were a high patient age, better PS, avoidance of extensive tumor resection, more frequent use of chemotherapy, and improved survival. The recent improvement in survival may be due to improvements in second-line treatment and supportive care.

Radiation therapy for primary central nervous system lymphoma

Up until the late 1970s, radiation therapy played an important role in the treatment of primary central nervous system lymphoma (PCNSL) but more recently its role has changed due to the increased use of systemic chemotherapy. In this article, the current status of radiotherapy for PCNSL and optimal forms of radiotherapy, including the treatment volume and radiation dose, are discussed. Data from nationwide Japanese surveys of PCNSL patients treated with radiation therapy suggest that the prognosis of PCNSL patients improved during the 1990s, in part due to the use of high-dose methotrexate-containing chemotherapy. The prognosis of patients treated with radiation alone also improved. Radiotherapy still seems to play an important role in the attempt to cure this disease.

Current and emerging pharmacotherapies for primary CNS lymphoma

Primary central nervous system lymphoma (PCNSL) constitutes a rare group of extranodal non-Hodgkin's lymphoma (NHL) primarily of B cell origin. It occurs in both immuno-competent and immune-compromised patients. High dose m ethotrexate (HD-MTX) based chemotherapy is the standard therapy. Chemotherapy with whole brain radiation therapy (WBRT) improves response rates and survival compared with WBRT alone. However, due to the increased risk for neurotoxicity with WBRT, recent studies have focused on using chemotherapy alone. Methotrexate based multi-agent chemotherapy without WBRT is associated with similar t reatment rates and survival compared with regimens that include WBRT although controlled trials have not been performed. Because of the low incidence of this disease, it is difficult to conduct randomized controlled trials. In this article we have discussed about the past, present and emerging treatment options in patients with PCNSL.

Changes in neurocognitive functioning and quality of life in adult patients with brain tumors treated with radiotherapy

This review aims to summarize what is currently known about neurocognitive outcome and quality of life in patients with brain tumors treated with radiotherapy. Whether potential tumor-controlling benefits of radiotherapy outweigh its potential toxicity in the natural history of brain tumors is a matter of debate. This review focuses on some of the adult main brain tumors, for which the issue of neurocognitive decline has been thoroughly studied: low-grade gliomas, brain metastases, and primary central nervous system lymphomas. The aims of this review are: (1) the analysis of existing data regarding the relationship between radiotherapy and neurocognitive outcome; (2) the identification of strategies to minimize radiotherapy-related neurotoxicity by reducing the dose or the volume; (3) the evidence-based data concerning radiotherapy withdrawal; and (4) the definition of patients subgroups that could benefit from immediate radiotherapy. For high grade gliomas, the main findings from literature are summarized and some strategies to reduce the neurotoxicity of the treatment are presented. Although further prospective studies with adequate neuropsychological follow-up are needed, this article suggests that cognitive deficits in patients with brain tumor have a multifactorial genesis: radiotherapy may contribute to the neurocognitive deterioration, but the causes of this decline include the tumor itself, disease progression, other treatment modalities and comorbidities. Treatment variables, such as total and fractional dose, target volume, and irradiation technique can dramatically affect the safety of radiotherapy: optimizing radiation parameters could be an excellent approach to improve outcome and to reduce neurotoxicity. At the same time, delayed radiotherapy could be a valid option for highly selected patients.