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How I treat "Double Hit" lymphoma

Jonathan W. Friedberg

Abstract

The 2016 revision of the WHO classification for lymphoma classification has included a new category of lymphoma, separate from diffuse large B-cell lymphoma termed High grade B-cell lymphoma with translocations involving myc and bcl-2 or bcl-6. These lymphomas, which occur in less than 10% of cases of diffuse large B-cell lymphoma, have been referred to as "double hit" lymphomas (or triple hit lymphomas if all three rearrangements are present). It is important to differentiate these lymphomas from the larger group of "double expressor" lymphomas which have increased expression of MYC and BCL-2 and/or BCL-6 by immunohistochemistry, using variable cut-off percentages to define positivity. Double hit lymphomas have a poor prognosis when treated with standard chemoimmunotherapy, and have increased risk of central nervous system involvement and progression. Double hit lymphomas may arise as a consequence of transformation of underlying indolent lymphoma. There are no published prospective trials in double hit lymphoma, however retrospective studies strongly suggest that "aggressive" induction regimens may confer superior outcome. In this manuscript, I review my approach to the evaluation and treatment of double hit lymphoma, with an eye toward future clinical trials incorporating rational targeted agents into the therapeutic armamentarium.

  • Submitted April 18, 2017.
  • Accepted May 25, 2017.