Potential mechanisms of spontaneous regression in patients with B-cell lymphoma; the significance of co-stimulatory molecules in lymphoma cells

Spontaneous regression in mature T-cell non-Hodgkin lymphoma

INTRODUCTION

Spontaneous regression (SR) is observed in some patients with mature T-cell non-Hodgkin lymphoma (MTCL), including adult T-cell leukemia/lymphoma (ATL), although the incidence is rare.

AREA COVERED

We extracted 31 cases with MTCL who experienced SR based on a literature search and summarized the patient characteristics and clinical outcomes.

EXPERT OPINION

MTCL with SR included various subtypes, the most common being ATL (n = 17). Five of 24 cases (21%) maintained SR for more than 5 years, and the median duration of SR was 2 years. Sixteen of 31 cases (52%) experienced tumor relapse after SR. Two retrospective studies including ATL cases showed SR rates of 18% and 4%, respectively. Representative triggers are infection and surgical biopsies, and possible mechanisms include immunological mechanisms such as cross-reactivity of virus-specific T cells with tumor antigens. The diagnostic criteria for SR are not standardized among reports, and the clinical outcomes are not fully described. Practically, observation is the only accepted strategy after SR was achieved. In the era of molecular targeted therapy or immunotherapy, new strategies including maintenance therapy after SR could be discussed, although clinical data are lacking.