Toward a Risk-Tailored Therapeutic Policy in Mantle Cell Lymphoma.

PURPOSE OF REVIEW: Mantle cell lymphoma (MCL) prognosis is strictly related to the characteristics of the disease, which can range from very indolent cases to highly aggressive and refractory ones. Here we will review the current knowledge on MCL biomarkers. RECENT
FINDINGS: Biomarker-informed diagnosis is essential for differentiating MCL from other mature B cell tumors. Diagnosis of MCL relies on the identification of the t(11;14) translocation by FISH or the consequently aberrant expression of cyclin D1 by immunohistochemistry. For the few cases staining negative for cyclin D1, SOX11 may help to define the diagnosis. Prognostic biomarkers have been proposed to stratify MCL patients, including baseline clinical aspects (leukemic non-nodal presentation, in situ presentation, Mantle cell International Prognostic Index-MIPI), pathological aspects (blastoid morphology, Ki-67 proliferation index, SOX11 expression), genetic aspects (immunoglobulin gene mutation status, TP53 deletion or mutation, CDKN2A deletion), and depth of response after treatment (PET imaging, molecular minimal residual disease). Such tools are increasingly used as a guide for therapeutic decisions. Watchful waiting approach is recommended for patients harboring favorable clinico-biological features, such as leukemic non-nodal presentation, low MIPI score, non-blastoid disease, low Ki-67 proliferation rate, mutated immunoglobulin genes, and the lack of SOX11 expression. For patients in need of frontline therapy, the decision of whether to undertake intensive regimens is based upon patient's age and comorbidities. Central nervous system prophylaxis is recommended for cases showing blastoid morphology. The duration of remission is tightly correlated to the depth of response. With the aim of achieving a longer duration of remission and survival, younger patients may pursue more intensive regimens incorporating high-dose cytarabine, followed by myeloablative consolidation chemotherapy, autologous stem cell transplantation, and rituximab maintenance. Older patients could, on the other hand, benefit from lower intensity immunochemotherapy followed or not by a maintenance therapy depending on which frontline regimen is used. Despite the identification of several potential useful biomarkers that may inform the treatment decisions and the design of clinical trials, the treatment choice remains nowadays determined by the patient age and fitness rather than by the individual patient characteristics. Tailoring therapy toward a risk-adapted strategy to accommodate the wide spectrum of disease is an urgent challenge, and clinical trials may explore the feasibility of a biomarker-defined therapeutic policy.