Author disclosures Alejandro Ariel Gru is a paid consultant for Seattle Genetics and has an ongoing relationship with Innate Pharma. John Zic is a site principal investigator for clinical trials for products from Elora and Galderma. The other authors report no actual or potential conflicts of interest with regard to this article.
Disclaimer The opinions expressed herein are those of the authors and do not necessarily reflect those of Federal Practitioner, Frontline Medical Communications Inc., the US Government, or any of its agencies. The manufacturers did not provide equipment or other forms of material support.
The following is a lightly edited transcript of a teleconference recorded in April 2019.
John Zic, MD. Let’s start by defining cutaneous T-cell lymphomas (CTCLs) and how they differ from other non-Hodgkin lymphomas. We also should discuss classification, which can be very confusing and epidemiology as it relates to the veteran population. Then I think we should dive into challenges with diagnosis and when should a VA or any provider consider mycosis fungoides (MF) and Sézary syndrome—the 2 most common variants of CTCLs.
I like to define the primary CTCLs as malignancies of the T-cell where the primary organ of involvement is the skin. However, this disease can spread to lymph nodes and visceral organs and the blood compartment in more advanced patients. Alejandro, could you provide some highlights about how CTCLs are classified?
Alejandro Ariel Gru, MD. Lymphomas are divided in the general hematology/oncology practice as Hodgkin and non-Hodgkin lymphomas. Traditionally all lymphomas that occur on the skin are non-Hodgkin lymphoma subtypes. That has specific connotations in terms of diagnosis, prognosis, and therapy. Because the T cells are one of the main residents of the subtypes of lymphocytes you encounter on the skin, most lymphomas that occur on the skin are derived of T-cell origin. B-cell lymphomas, in general, tend to be relatively uncommon or more infrequent.
There are 3 main subtypes of CTCL that present on the skin.1 MF is, by far, the most common subtype of CTCL. The disease tends to present in patients who are usually aged > 60 years and is more frequent in white males. It’s a lymphoma that is particularly relevant to the veteran population. The second subtype has many similarities to MF but shows substantial peripheral blood involvement and is referred to as Sézary syndrome. The third group is encompassed under the term CD30-positive lymphoproliferative disorders. This group includes 2 main subtypes: primary cutaneous anaplastic large-cell lymphoma and lymphomatoid papulosis. Some cases of MF develop progression to what we call large cell transformation, which implies cytologic transformation to a more aggressive lymphoma.
There are other cutaneous lymphomas that are far less common. Some are indolent and others can be more aggressive, but they represent < 5% of all CTCL subtypes.
Lauren Pinter-Brown, MD. That was a great summary about these non-Hodgkin lymphomas. In the veteran population, it’s wise to remember that there are many kinds of non-Hodgkin lymphomas. Because of the action that they have seen, some people, such as Vietnam veterans, might be more susceptible to non-Hodgkin lymphomas than others.
John Zic. That’s a good point because certainly non-Hodgkin lymphomas are listed as one of the potential disease associations with exposure to Agent Orange.
I’d like to move on to epidemiology and the incidence of MF and Sézary syndrome. An article that came out of Emory University in 2013 is one of the more up-to-date articles to examine the incidence and survival patterns of CTCL.2 The authors looked at patients from 2005 to 2008 and identified 2,273 patients in the Surveillance, Epidemiology, and End Results registry. They estimated that the incidence of MF in the US population is about 5.5 per 1,000,000 per year, which certainly makes it a rare disease. The incidence of Sézary syndrome was 0.1 per 1,000,000 per year, which comes out to about 1 per 10 million per year.
However, the MF incidence needs to be contrasted to the estimated incidence in the veteran population. In 2016, Larisa Geskin and colleagues from Columbia University and the Bronx US Department of Veterans Affairs (VA) Medical Center examined the VA database of patients with diagnoses of MF and Sézary syndrome.3 They combined them, but I have a feeling that the amount of Sézary syndrome patients was much less than those with MF. They estimated an incidence per million of 62 to 79 cases per 1,000,000 per year. The conclusion of Dr. Geskin’s study stated that the incidence of CTCL in the veteran population appears to be anywhere from 6 to 8 times higher. But if we use the most recent US incidence rates, it’s more than 10 times higher.
Those of you who have worked with veterans, either at the VA or in your private practice, do you have any ideas about why that might be?
