Mantle cell lymphoma (MCL) is a biologically heterogeneous disease, and patients may experience a clinical course ranging from indolent to very aggressive. Observational studies suggest that a subset of patients can be safely observed for a period of months to years from initial diagnosis without adversely impacting their outcomes. However, identification of candidates for the "watch and wait" approach remains challenging because selection criteria are not well-defined. Studies that prospectively stratify patients on the basis of MCL biology and disease risk will be informative, and patients with indolent MCL may be ideal candidates for frontline clinical trials exploring novel therapies.
