A single-center retrospective analysis of outcome measures and consolidation strategies for relapsed and refractory primary CNS lymphoma

Evaluation of progression-free survival as a surrogate end point in primary CNS lymphoma: a systematic review and meta-analysis

Purpose: To evaluate progression-free survival (PFS) as early surrogate endpoints for overall survival (OS) in primary CNS lymphoma (PCNSL). Methods: PubMed, Embase and Cochrane Central Library were searched up to 7 June 2022. Trial-level analyses were performed by weighted linear regression of logarithmic hazard ratios for PFS and OS. Treatment arm-level analyses were performed between PFS rates and 3- or 5-year OS rates. Results: 1471 PCNSL patients in nine randomized control trials were included. PFS was associated with OS (r = 0.750; 95% CI: 0.228-0.937). Strong linear correlations existed between 1-, 2- and 3-year PFS and 3-year OS (r = 0.896-0.928), moderate or weak correlations existed between 3- to 6-month PFS and 3-year OS, 3-month to 5-year PFS and 5-year OS. Conclusion: Short-term PFS can validly substitute for long-term OS in PCNSL.

Impact of Thiotepa-Based Autologous Hematopoietic Cell Transplantation in Primary Central Nervous System Lymphoma in First Complete Remission: A University of California Hematologic Malignancies Consortium Retrospective Analysis

BACKGROUND

The choice between nonmyeloablative chemotherapy (NMA-C) or autologous hematopoietic cell transplantation (autoHCT) as consolidation in primary central nervous system lymphoma (PCNSL), and timing of autoHCT differs among centers. We aimed to clarify these points.

METHODS

We retrospectively analyzed PCNSL adult patients who received consolidation in CR1 or underwent autoHCT during their treatment course. Cohort A included those who underwent autoHCT in CR1, cohort B included those who underwent NMA-C in CR1, and cohort C included patients who underwent autoHCT in CR2+. We compared cohorts A and B, and cohorts A and C. The primary endpoint was overall survival (OS), and secondary endpoints were progression-free survival (PFS), treatment-related mortality (TRM) and cumulative incidence of relapse (CIR).

RESULTS

36 patients were included in cohort A, 30 in cohort B, and 14 in cohort C. The 5-year OS for cohorts A vs B and vs C were 90.7% vs 62.8% (P = .045) and vs 77.9% (P = .32), respectively. The 5-year PFS from diagnosis for cohorts A vs B was 87.8% vs 37.3% (P < .001). The 5-year PFS from autoHCT for cohorts A vs C was 87.6% vs 58.4% (P = .023). The 5-year TRM and CIR in cohorts A vs B was 9.4% vs 9.5% (P = .674), and 2.9% vs 53.2% (P < .001), respectively. The 5-year TRM and CIR in cohorts A vs C from the time of autoHCT was 9.5% vs 22.1% (P = .188), and 2.9% vs 19.5% (P = .104), respectively.

CONCLUSION

Despite the limitations, thiotepa-based autoHCT in CR1 appears to improve outcomes in eligible patients with PCNSL.

Temporalis muscle thickness predicts early relapse and short survival in primary CNS lymphoma

Background

Most patients with primary CNS lymphoma (PCNSL) achieve durable remission whereas a minority die in the first year. Sarcopenia is a powerful predictor of mortality in the brain and systemic cancers. Temporalis muscle thickness (TMT) is a validated radiographic measure of sarcopenia. We hypothesized that patients with thin TMT at diagnosis would have early progression and short survival.

Methods

Two blinded operators retrospectively measured TMT in 99 consecutive brain MRIs from untreated patients with PCNSL.

Results

We generated a receiver operator characteristic curve and chose a single threshold defining thin TMT in all patients as <5.65 mm, at which specificity and sensitivity for 1-year progression were 98.4% and 29.7% and for 1-year mortality were 97.4% and 43.5% respectively. Those with thin TMT were both more likely to progress (P < .001) and had higher rates of mortality (P < .001). These effects were independent of the effect of age, sex, and Eastern Cooperative Oncology Group performance status in a cox regression. Memorial Sloan Kettering Cancer Center score did not predict progression-free survival or overall survival as well as TMT. Patients with thin TMT received fewer cycles of high-dose methotrexate and were less likely to receive consolidation but neither variable could be included in the Cox regression due to violation of the proportional hazards assumption.

Conclusions

We conclude that PCNSL patients with thin TMT are at high risk for early relapse and short survival. Future trials should stratify patients by TMT to avoid confounding.

Diagnosis and Treatment Using Autologous Stem-Cell Transplantation in Primary Central Nervous System Lymphoma: A Systematic Review

BACKGROUND

Consolidation therapy has improved the outcome of newly diagnosed PCNSL patients. Whole-brain radiotherapy (WBRT) was the first consolidation strategy used and represented the gold standard for many years, but at the expense of a high risk of neurotoxicity. Thus, alternative strategies are being investigated in order to improve disease outcomes and to spare the neurocognitive side effects due to WBRT.

METHODS

We reviewed published studies on PCNSL patients treated with HDC/ASCT, focusing on the efficacy and safety of the conditioning regimens. Prospective and retrospective studies, published in the English language from 1992 to 2022, in high-quality international journals were identified in PubMed.

RESULTS

Consolidation with HDC containing highly CNS-penetrating agents (thiotepa, busulfan or BCNU) followed by ASCT provided long-term disease control and survival in PCNSL patients. Two prospective randomized studies, comparing HDC/ASCT versus WBRT, reported similar progression-free survival (PFS) and similar results on the decline in neurocognitive functions in a substantial proportion of patients after WBRT but not after HDC-ASCT. A recent randomized study comparing HDC/ASCT versus non-myeloablative consolidation reported a longer PFS in transplanted patients.

CONCLUSION

ASCT conditioned with regimens, including highly CNS-penetrating agents, represents, to date, the best choice among the available consolidation strategies for fit newly diagnosed PCNSL patients.

Sustained Complete Remission in Multi-Relapsed Primary CNS Lymphoma Treated with Ibrutinib Monotherapy: A Case Report

Primary CNS lymphoma (PCNSL) is a highly aggressive malignant disease with a high recurrence rate and a poor prognosis. We present the case of a 71-year-old woman diagnosed with PCNSL in June 2010. After 3 relapses and intensive treatment with multiple chemotherapy regimens and whole-brain radiotherapy, she received off-label treatment with the Bruton tyrosine kinase inhibitor ibrutinib, responded well, achieved a complete remission, and is progression-free for now >3 years.