Mycosis fungoides (MF) is the most common form of cutaneous T-cell lymphoma (CTCL). Because of that, the terms MF and CTCL are often used interchangeably, and sometimes imprecisely. For example, much of the research on MF reported in the medical journals is listed under the name CTCL, even though MF is just one type of CTCL. This can be a source of confusion. All cases of MF are CTCL, but not all CTCL cases are MF. Mycosis fungoides can appear anywhere on the body but tends to affect areas of the skin protected from sun by clothing.
MF is an indolent type of CTCL, follows a slow, chronic course and very often does not spread beyond the skin. Over time, in about 10% of cases, it can progress to lymph nodes and internal organs. Symptoms of MF can include flat, red, scaly patches, thicker raised lesions calls plaques, and sometimes large nodules called tumors. The disease can progress over many years, often decades.
Although there is continuing research, at this time no single factor has been proven to cause this disease. There is no supportive research indicating that it is genetic or hereditary. Studies have failed to show connections between chemical exposure, environment, pesticides, radiation, allergies and occupations. Exposure to Agent Orange may be a risk factor for developing CTCL for veterans of the Vietnam War, but no direct cause-effect relationship has been established.
While the number of new cases diagnosed each year is relatively low (about 3,000), it is estimated that, since patients have a very long survival, there may be as many as 30,000 patients living with cutaneous lymphoma in the United States and Canada. Due to the difficulty of diagnosing the disease in its early stages and the lack of an accurate reporting system, these numbers are estimates.
Stuart Lessin, MD, Medical Director, KGL Skin Study Center, Broomall, PA
Pierluigi Porcu, MD, Director, Hematologic Malignancies and Hematopoietic Stem Cell Transplantation Division, Sidney Kimmel Cancer Center, Thomas Jefferson University Hospital (At time of publication: Associate Professor of Internal Medicine, Division of Hematology-Oncology, Ohio State University Comprehensive Cancer Center)
Larisa Geskin, MD, Director, Cutaneous Oncology, Columbia University Medical Center (At time of publication: Associate Professor of Dermatology, University of Pittsburgh)
One of the challenges in describing this disease is that it doesn’t look the same for all patients. Patches, plaques and tumors are the clinical names for different skin manifestations and are generally defined as “lesions.”
- Patches are usually flat, often scaly and look like a “rash.”
- Plaques are thicker, raised lesions. MF patches and plaques are often mistaken for eczema, psoriasis or “non-specific” dermatitis until an exact diagnosis is made.
- Tumors are raised “bumps” or “nodules” which may or may not ulcerate (open sores).
A common characteristic is itching, although not all patients experience this symptom. Most of the time patients present with patches or plaques. Only rarely are the tumors the presenting lesion. While it is possible to have all three of these types of lesions at the same time, most people who have had the disease for many years experienced only one or two types of lesions, generally patches and plaques.
In cutaneous lymphoma, and particularly in mycosis fungoides, in the early stages of the disease, the lymphoma cells are mostly limited to the skin, and one can have excellent and long-lasting responses with just skin directed therapy. “Skin directed therapy” includes treatments that stay in the skin, such as ultraviolet light, radiation, and topical drugs (i.e., steroids, nitrogen mustard, and retinoids that are applied directly to the skin).
The term systemic therapy defines any drug treatment that, after absorption, reaches the bloodstream and is therefore distributed across the body “system.” Any drug that is taken by mouth, given as a suppository, injected under the skin, taken under the tongue, or directly infused through a blood vessel will eventually reach all body organs and tissues (including the skin), with the exception of the brain, which by design is protected by a specific “barrier.” In patients who have only partial or short responses to phototherapy or topical drugs, and certainly in more advanced stages, the use of systemic therapy is warranted.
The rationale for combining skin directed and systemic therapies, even in patients with skin limited disease, is what one could call a “sandwich effect.” Skin directed therapy works from the outside in and systemic therapy works from the inside out. In addition, there is evidence that skin directed therapies and systemic therapies may enhance each other’s effect against the lymphoma cells.
*Excerpt from "AN OVERVIEW OF SYSTEMIC THERAPIES", Pierluigi Porcu, MD, Sidney Kimmel Cancer Center
Article previously published in the Cutaneous Lymphoma Foundation's Forum Spring/Summer 2012 newsletter.