Plasmablastic lymphoma after standard-dose temozolomide for newly diagnosed glioblastoma

Metronomic treatment in immunocompetent preclinical GL261 glioblastoma: effects of cyclophosphamide and temozolomide

Glioblastoma (GBM) causes poor survival in patients even when applying aggressive treatment. Temozolomide (TMZ) is the standard chemotherapeutic choice for GBM treatment, but resistance always ensues. In previous years, efforts have focused on new therapeutic regimens with conventional drugs to activate immune responses that may enhance tumor regression and prevent regrowth, for example the "metronomic" approaches. In metronomic scheduling studies, cyclophosphamide (CPA) in GL261 GBM growing subcutaneously in C57BL/6 mice was shown not only to activate antitumor CD8⁺ T-cell response, but also to induce long-term specific T-cell tumor memory. Accordingly, we have evaluated whether metronomic CPA or TMZ administration could increase survival in orthotopic GL261 in C57BL/6 mice, an immunocompetent model. Longitudinal in vivo studies with CPA (140 mg/kg) or TMZ (range 140-240 mg/kg) metronomic administration (every 6 days) were performed in tumor-bearing mice. Tumor evolution was monitored at 7 T with MRI (T₂ -weighted, diffusion-weighted imaging) and MRSI-based nosological images of response to therapy. Obtained results demonstrated that both treatments resulted in increased survival (38.6 ± 21.0 days, n = 30) compared with control (19.4 ± 2.4 days, n = 18). Best results were obtained with 140 mg/kg TMZ (treated, 44.9 ± 29.0 days, n = 12, versus control, 19.3 ± 2.3 days, n = 12), achieving a longer survival rate than previous group work using three cycles of TMZ therapy at 60 mg/kg (33.9 ± 11.7 days, n = 38). Additional interesting findings were, first, clear edema appearance during chemotherapeutic treatment, second, the ability to apply the semi-supervised source analysis previously developed in our group for non-invasive TMZ therapy response monitoring to detect CPA-induced response, and third, the necropsy findings in mice cured from GBM after high TMZ cumulative dosage (980-1400 mg/kg), which demonstrated lymphoma incidence. In summary, every 6 day administration schedule of TMZ or CPA improves survival in orthotopic GL261 GBM with respect to controls or non-metronomic therapy, in partial agreement with previous work on subcutaneous GL261.

Plasmablastic lymphoma following combination treatment with fludarabine and rituximab for nongastric mucosa-associated lymphoid tissue lymphoma: a case report and review of literature

Plasmablastic lymphoma (PBL) is an uncommon malignancy which predominantly occurs in the oral cavity of human immunodeficiency virus (HIV)-positive patients. Sporadic cases have been published describing PBL in immunocompetent patients as well as in immunodeficient patients following immunosuppressive therapy or transplantation. We hereby reported a case of PBL in a 69-year-old, HIV-negative male subjected to combination treatment with fludarabine and rituximab for nongastric mucosa-associated lymphoid tissue (MALT) lymphoma. The diagnosis of PBL was made with tumor cells of immunoblasts or plasmablasts morphology strongly positive for MUM-1, EMA and CD138, and partly positive for CD38, and negative for CD20, BCL-6, and CD56, and approximately 80% of which were positive for Ki-67. The case presented PBL after MALT, and a history of chemotherapy including fludarabine and rituximab led to the potential immunocompromised state. The patient died 5 months after the diagnosis of PBL.