Impact of Central Nervous System International Prognostic Index on the Treatment of Diffuse Large B Cell Lymphoma

Recent updates on central nervous system prophylaxis in patients with high-risk diffuse large B-cell lymphoma

The use of central nervous system (CNS) prophylaxis for patients with diffuse large B-cell lymphoma (DLBCL) remains controversial. Although uncommon, CNS relapses are invariably fatal in this otherwise curable disease. Accurate identification of patients at risk and the optimal approach to CNS prophylaxis therefore remains an area of unmet need. The existing literature, largely retrospective in nature, provides mixed conclusions regarding the efficacy of CNS prophylaxis. The utility of CNS prophylaxis has itself been challenged. In this review, we dissect the issues which render the value of CNS prophylaxis uncertain. We first compare international clinical guidelines for CNS prophylaxis. We then interrogate the factors that should be used to identify high-risk patients accurately. We also explore how clinical patterns of CNS relapse have changed in the pre-rituximab and rituximab era. We then discuss the efficacy of CNS-directed approaches, intensification of systemic treatment and other novel approaches in CNS prophylaxis. Improved diagnostics for early detection of CNS relapses and newer therapeutics for CNS prophylaxis are areas of active investigation. In an area where prospective, randomized studies are impracticable and lacking, guidance for the use of CNS prophylaxis will depend on rigorous statistical review of retrospective data.

Mutation profile of diffuse large B-cell lymphoma with relapses in the central nervous system

Introduction. The recurrence of diffuse large B-cell cell lymphoma in the central nervous system in the vast majority of cases is a fatal manifestation of the disease. The study of the lymphoma mutational profile can improve the accuracy of the prognosis of relapse in the central nervous system and justify the selection of patients for preventive treatment. Aim. To evaluate the mutational profile of cases of diffuse large B-cell cell lymphoma with central nervous system damage in relapse based on the results of our own experiment on high-performance sequencing.

Materials and methods. On the Illumina platform, full-exome sequencing of diagnostic samples of diffuse large B-cell cell lymphoma with relapses in the central nervous system was performed. A panel including more than 70 genes was analyzed.

Results. Four main groups of genetic events can be distinguished in the group of studied samples, namely: combined mutations in the NF-kB (MYD88, NOTCH1, CD79B, CARD11) and JAK-STAT (PIM1, STAT6) signaling pathways, as well as aberrations in the main oncosuppressor TP53 and chromatin remodeling system genes (ARID1A, KMT2D, EP300, SMARCA4). A recurrent mutation c. 794T>C, p.L265P MYD88 was detected in the study group. Among other findings, mutations in the CIITA and CD58 genes should be noted, which are important in avoiding tumor cells from immune surveillance.

Conclusion. Despite the apparent heterogeneity of the mutational profile of diffuse large B-cell cell lymphoma with relapses in the central nervous system, in most cases, tumor cells were characterized by genetic disorders leading to the production of a large number of pro-inflammatory cytokines by malignant lymphocytes, as well as aberrations that reduce immunogenicity and contribute to the avoidance of immune surveillance by the tumor.