The biology and management of systemic anaplastic large cell lymphoma

Systemic anaplastic large cell lymphoma (ALCL) is an aggressive CD30(+) non-Hodgkin lymphoma. Anaplastic lymphoma kinase-positive (ALK+) ALCL is associated with the NPM-ALK t(2;5) translocation, which is highly correlated with the identification of the ALK protein by immunohistochemistry. ALK+ ALCL typically occurs in younger patients and has a more favorable prognosis with 5-year survival rates of 70% to 90% in comparison with 40% to 60% for ALK-negative (ALK-) ALCL. Studies support young age as a strong component of the favorable prognosis of ALK+ ALCL. Until recently, no recurrent translocations were identified in ALK- ALCL. However, emerging data now highlight that ALK- ALCL is genetically and clinically heterogeneous with a subset having either a DUSP22 translocation and a survival rate similar to ALK+ ALCL or a less common P63 translocation, the latter associated with an aggressive course. Anthracycline-based regimens such as cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) remain the standard first-line treatment choice for systemic ALCL, but in many patients with ALK- ALCL, it is ineffective, and thus it is often followed by consolidative autologous stem cell transplantation. However, selection of appropriate patients for intensified therapy remains challenging, particularly in light of genetic and clinical heterogeneity in addition to the emergence of new, effective therapies. The antibody drug conjugate brentuximab vedotin is associated with a high response rate (86%) and durable remissions in relapsed/refractory ALCL and is under investigation in the first-line setting. In the future, combining clinical and genetic biomarkers may aid in risk stratification and help guide initial patient management.