Patients who have a rare subtype of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) with isolated Hodgkin/Reed–Sternberg-like cells (CLL-HRS) may benefit from Hodgkin-directed therapy, based on data from 46 individuals.
Those patients who progress to classic Hodgkin lymphoma (CHL) from CLL/SLL are generally diagnosed based on straightforward pathology and treated with HRS cells in the same way as patients with de novo CHL, wrote lead author Dr. Rebecca L. King, a pathologist at the Mayo Clinic in Rochester, Minn.
Given the rarity of CLL-HRS, data on patient management are limited, they noted.
In a retrospective study published in Blood Cancer Journal, researchers reviewed outcome data from 15 adults with CLL-HRS and 31 adults with CLL/SLL who had overtly transformed to CLL-HL. The median age of the participants at the time of CLL-HL or CLL-HRS transformation diagnosis was 72 years; 71% and 87% of the CLL-HL and CLL-HRS patients, respectively, were male.
The median times from CLL to CLL-HL transformation and from CLL to CLL-HRS transformation were 6.6 years and 4.9 years, respectively; the difference was not statistically significant. The phenotypic features of Reed-Sternberg cells and Epstein-Barr virus status were similar in both patient groups. Two patients had biopsies in which both CLL-HRS and CLL-HL were present in the same tissue at initial diagnosis; they were included in the CLL-HL group for clinical analysis and in both groups for pathology analysis.
The median overall survival of CLL-HRS patients was 17.5 months, compared with 33.5 months for CLL-HL patients (P = .24), a nonsignificant difference. However, patients with CLL-HRS who received Hodgkin-directed therapy had a significantly longer median overall survival, compared with those who received CLL-directed therapy (57 months vs. 8.4 months, P = .02).
CLL-directed therapy included rituximab with or without corticosteroids, chemoimmunotherapy, or acalabrutinib; HL-directed therapy included doxorubicin hydrochloride, bleomycin sulfate, vinblastine sulfate, and dacarbazine–based treatment; radiotherapy; or BCVPP (carmustine, cyclophosphamide, vinblastine, procarbazine, and prednisone).
Histopathology findings showed that CLL-HL patients had a background of mixed inflammation that was distinct from findings in CLL/SLL. CLL-HRS patients had a minimal inflammatory background, compared with CLL-HL cases, but researchers identified rosetting of T cells around the HRS cells in 56% of these patients.
“Our findings suggest that, clinically and pathologically, these patients show a spectrum of findings, and these two entities likely exist on a biologic continuum. Furthermore, our findings suggest that CLL-HRS patients managed with Hodgkin-directed therapy, rather than CLL-directed therapy, may have superior outcomes,” the researchers wrote.
The study findings were limited by several factors, including the retrospective design and the use of data from a single center. Therefore, the results should be validated in other cohorts, the researchers noted. In addition, the study participants were diagnosed over three decades, and management of the condition has significantly improved.
However, the results were strengthened by a review of data by three pathologists who were blinded to the clinical outcomes, they said.
“These findings have important implications for a scenario in which clinical guidelines are lacking and suggest that hematologists treating patients with CLL-HRS should consider HL-directed therapy,” the researchers concluded.
In an interview, Jennifer A. Woyach, MD, a hematologist at Ohio State University, Columbus, commented on the study findings: “Hodgkin transformation and CLL with Hodgkin-like cells likely represent a biologic continuum, and care should be taken to obtain adequate biopsies, so that the diagnosis of Hodgkin transformation can be made when appropriate.”
“Interestingly, the authors noted a trend toward improved survival when CLL with Hodgkin-like cells was treated with standard Hodgkin regimens,” said Dr. Woyach. “With the small patient numbers, this certainly cannot be a general recommendation, but should be considered by treating physicians on a case-by-case basis.”
“While we know that patients with Hodgkin transformation can in many cases be successfully treated with standard Hodgkin regimen, the natural history and optimal treatment for CLL with Hodgkin-like cells have been unknown. This analysis helps understand the biologic difference between these two clinicopathologic entities to understand how to better treat patients,” she noted. Going forward, “it would be extremely helpful to see these data validated by other centers to be sure that these results are reproducible,” Dr. Woyach added.
The study was supported by the Mayo Clinic, Rochester, Minn., and by the Henry J. Predolin Foundation. Lead author Dr. King disclosed research support to her institution from Bristol-Myers Squibb/Celgene. Dr. Woyach had no financial disclosures relevant to this study, but she has received laboratory research funding from Schrodinger and has consulted for AbbVie, Pharmacyclics, Janssen, AstraZeneca, Genentech, Beigene, Loxo, and Newave.
This article was updated 3/11/22.