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.

The viral load of Epstein-Barr virus (EBV) DNA in peripheral blood predicts for biological and clinical characteristics in Hodgkin lymphoma

PURPOSE

The Epstein-Barr virus (EBV) is present in the malignant Hodgkin/Reed-Sternberg (HRS) cells of 20% to 40% cases of Hodgkin lymphoma (HL) in Western countries. We were interested in the detection and quantification of cell-free plasma EBV-DNA as an indicator of biological and clinical characteristics in EBV-associated HL.

EXPERIMENTAL DESIGN

EBV was detected in peripheral blood compartments (whole blood, plasma, and mononuclear cells) at diagnosis by real-time PCR for the EBNA (EB nuclear antigen) region (n = 93) and in HRS cells by in situ hybridization for EBV-encoded small RNAs (EBER; n = 63). These data were correlated to histological and clinical characteristics, EBV serology, circulating cell-free DNA, and interleukin (IL)-6 levels.

RESULTS

Detection of EBV-DNA in plasma had a high specificity (90%), but a relatively low sensitivity (65%) to predict for EBV association. The viral load was higher in patients with advanced stage disease, older age in the presence of B-symptoms, and international prognostic score more than 2. The presence of EBV in HRS cells and higher plasma EBV-DNA copy numbers correlated to an increased frequency of tumor-infiltrating CD68+ macrophages in lymph node biopsies. Plasma EBV-DNA load correlated to circulating cell-free DNA and IL-6 levels, and inversely correlated to lymphocyte counts and EBNA1 antibody titers.

CONCLUSION

Although the presence of EBV-DNA in peripheral blood cannot be regarded as a surrogate marker for EBER, the plasma EBV-DNA load at HL diagnosis is an indicator of disease activity and biological characteristics associated with negative prognosis. Moreover, the inverse correlation to EBNA1 antibody titers and lymphocyte counts may indicate a reduction in immunosurveillance, favoring the expansion of EBV-HRS cells in HL.

Glutathione-S-transferase genotypes influence prognosis in follicular non-Hodgkin's Lymphoma

Polymorphisms in detoxification enzymes of the glutathione S-transferase (GST) family have been associated with risk and prognosis of several cancer types. We studied deletions of GSTM1 and GSTT1, and the GSTP1 Ile(105)Val polymorphism in 89 patients with follicular lymphoma (FL). Patients with a GSTM1 or GSTT1 deletion had a significantly worse event-free survival, when compared with patients with undeleted genotype (p = 0.03 and p = 0.03, respectively). Outcome was even worse in patients with a double negative genotype, in comparison with patients with only one GST deletion or normal genotype (p = 0.01). In the multivariate analysis, the GSTM1/GSTT1 genotype tended to have a prognostic significance independent from the Follicular Lymphoma International Prognostic Index (FLIPI) score. In particular, GSTM1/T1 deletions identified patients with negative prognosis in the low (<3) FLIPI score group (p = 0.01). Larger prospective studies including homogeneously treated patients will be needed to confirm these results.

[An in-vitro study of the antimicrobial activity of copper and zinc salts on pure and mixed microbial cultures]

The authors evaluated the in vitro antimicrobial activity of some copper and zinc salts. The results showed high antimicrobial activity of copper salts versus S. mutans and versus the bacterial association tested in this study.