Primary central nervous system lymphoma: a narrative review of ongoing clinical trials and goals for future studies

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.

Primary Central Nervous System Lymphoma Presenting as Isolated Multiple Cranial Neuropathies: An Extremely Rare Case

Primary central nervous system lymphoma (PCNSL) is an uncommon malignancy of B-cell origin that typically involves the brain, eyes, and spinal cord without systemic spread. PCNSL typically involves the cerebral hemispheres, basal ganglia, or periventricular region. Isolated leptomeningeal PCNSL without any evidence of parenchymal involvement is very rare. We present a very unusual case of PCNSL presenting as persistent bilateral Bell's palsy and trigeminal neuralgia with magnetic resonance imaging (MRI) brain showing significantly hypertrophied enhancing bilateral facial and trigeminal nerves.

Karnofsky Performance Status and quality of life in patients with relapsed or refractory primary CNS lymphoma from a phase I/II study of tirabrutinib

Background

Tirabrutinib, a second-generation inhibitor of Bruton's tyrosine kinase, was approved in March 2020 for the treatment of relapsed or refractory primary central nervous system lymphoma (r/r PCNSL) based on phase I/II studies in Japan. We previously reported the overall response rate and safety profile. We describe Karnofsky Performance Status (KPS) and the quality of life (QoL) in patients with r/r PCNSL receiving tirabrutinib based on more than 1-year follow-up data.

Methods

Patients with r/r PCNSL, age ≥20 years, and KPS ≥70 were treated with tirabrutinib once daily at a dose of 320, 480, or 480 mg under fasted conditions. QoL was assessed using questionnaires issued by the European Organization for Research and Treatment of Cancer (EORTC), namely EORTC QLQ-C30, EORTC QLQ-BN20, and EuroQol 5 dimensions 3-level (EQ-5D-3L) along with KPS.

Results

Forty-four patients (mean age, 60 years [range 29-86]) were enrolled. The median follow-up period was 14.9 months (range, 1.4-27.7). The median KPS of the patients at baseline was 80.0 (range, 70-100), and this remained constant during the treatment. The global health status/QoL in the QLQ-C30 showed significant improvements from baseline through cycles 3-17 and remained relatively constant thereafter until cycle 23. Improvements were also seen in emotional functioning and constipation in the QLQ-C30 segments. Other items of QLQ-C30 and QLQ-BN20, EQ-5D visual analog scales, and EQ-5D index were maintained during the treatment.

Conclusions

Tirabrutinib generally maintains KPS and QoL scores with some improvements in specific QoL items in patients with r/r PCNSL.

High-dose methotrexate and rituximab induction regimen in immunocompetent patients with primary CNS lymphoma: a retrospective single-center study of survival predictors

PURPOSE

Primary Central Nervous System Lymphoma (PCNSL) is an aggressive tumor that is confined to the CNS. Although the provision of high-dose methotrexate (HD-MTX) has remarkably improved outcomes in PCNSL patients, the optimal treatment regimens and standard MTX dose for induction therapy have been largely controversial. Herein, we sought to explore the impact of adjuvant rituximab and different dosages of induction HD-MTX on survival outcomes of immunocompetent patients with PCNSL.

METHODS

In this study, we examined patients with PCNSL treated at a single NCI-designated comprehensive cancer center to evaluate their survival outcomes. We conducted a retrospective analysis of 51 immunocompetent patients with PCNSL who received their induction chemotherapy at the University of Alabama at Birmingham (UAB) between 2001 and 2019. Only adult patients with a confirmed diagnosis of PCNSL who had either HD-MTX alone or in combination with rituximab were included. Patients' demographics, clinical characteristics, and survival data were collected and analyzed.

RESULTS

There is no significant difference in survival among patients who received MTX alone versus MTX plus rituximab (HR = 0.996 (95% CI: 0.398-2.493), p = 0.994). Lower doses of MTX were associated with worse survival outcomes (HR = 0.680 (95% CI: 0.530-0.872), p = 0.002); however, this difference in survival was not significant when adjusted to age (HR = 0.797 (95% CI: 0.584-1.088), p = 0.153).

CONCLUSION

Our experience challenges the role of rituximab in PCNSL during induction therapy. Our study also highlights the shorter survival in elderly patients with PCNSL which can be related, to some extent, to the relatively lower doses of HD-MTX. There is an unmet need to establish a consensus on the most effective upfront regimen in PCNSL through prospective studies.

Non-Myeloablative Chemotherapy as Consolidation Strategy After High-Dose Methotrexate-Based Chemoimmunotherapy in Patients With Primary CNS Lymphoma: A Retrospective Single Center Study in China

Primary central nervous system lymphoma (PCNSL) remains a disease with poor outcome and high recurrence rate. We retrospectively analyzed the clinical data of 243 immunocompetent patients with PCNSL in Beijing Tiantan Hospital. The median age of PCNSL patients was 57 years (range 10-95 years). For induction therapy, 94.7% of patients received high-dose methotrexate (HD-MTX) containing regimens, and 59.3% received rituximab, which increased over time. The overall response rate was 72.8%, with 58.8% achieving complete response. With a median follow-up of 27.0 months (95% confidence interval 23.6-30.4), the median progression-free survival (PFS) time was 14.0 months (95% CI 9.45-18.55), and the 2-year PFS rate was 33.2%. The median overall survival (OS) was not reached (NR), with an estimated overall survival rate at 4 years of 61.6%. Among 95 patients who completed sequential consolidation chemotherapy with either pemetrexed or etoposide plus cytarabine, the median PFS was 28 months (95% CI 17.11-38.89), and the estimated overall survival at 4 years was 78.7%. In conclusion, HD-MTX based induction chemotherapy with non-myeloablative sequential consolidation chemotherapy is an alternative feasible treatment option.