T-cell lymphoma is a type of blood cancer. It is a form of non-Hodgkin lymphoma that develops from an infection-fighting immune cell called a T cell. People with T-cell lymphoma have too many T cells that don’t work properly. These abnormal T cells crowd out other healthy blood cells. They accumulate in and affect other organs such as the skin, and they fail to effectively fight off infections. Rarely, a lymphoma may develop from a different kind of immune cell called a natural killer (NK) cell. NK-cell lymphomas are usually grouped with T-cell lymphomas, but they behave somewhat differently.

T-cell lymphomas make up about 6 percent to 10 percent of all non-Hodgkin lymphoma cases. About 17,000 people are diagnosed with T-cell lymphoma in the United States each year. The average age at diagnosis is 65 years old. This disease is more likely to affect men than women.

How Does T-Cell Lymphoma Differ From Other Types of Lymphoma?

The term “lymphoma” refers to any cancer that develops from lymphocytes. Lymphocytes are cells involved in the lymphatic system, which is a part of the body’s immune system. Lymphocytes’ main job is to protect the body from infections. There are three primary kinds of lymphocytes:

• B cells (or B lymphocytes) — These cells produce antibodies that help kill germs like bacteria and viruses.
• T cells (or T lymphocytes) — Some T cells also make antibodies, while others directly kill germs or help control other immune cells.
• Natural killer cells — NK cells can fight off cancerous cells and cells infected by viruses.

There are two general types of lymphoma. Hodgkin lymphoma contains large, abnormal cells called Reed-Sternberg cells. Non-Hodgkin lymphoma includes all other subtypes of lymphoma that don’t fall into this first category. Any non-Hodgkin subtype that develops from B cells is considered a B-cell lymphoma, and any subtype that develops from T cells or NK cells is considered a T-cell lymphoma.

Types of T-Cell Lymphoma

There are as many as 85 different subtypes of T-cell lymphoma, according to the World Health Organization. Some of the more common subtypes include:

• Angioimmunoblastic T-cell lymphoma (AITL) — AITL more often affects older adults and usually grows very quickly.
• T-cell lymphoblastic lymphoma (T-LL) — This condition affects males more than females. T-LL is more likely to be diagnosed in teens or young adults. This disease grows quickly but can have a good outlook.
• Cutaneous T-cell lymphoma (CTCL) — Mycosis fungoides, Sezary syndrome, and other CTCL subtypes develop in the skin and usually cause a patchy, itchy rash.
• Anaplastic large cell lymphoma (ALCL) — There are three subtypes of ALCL: Primary cutaneous ALCL primarily affects children and young adults; systemic ALCL is found more often in middle-aged people, and a rare type called breast implant-associated ALCL occurs in women who have had breast implants.
• Peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) — When someone has T-cell lymphoma that doesn’t fit into any other defined lymphoma subtype, they receive a diagnosis of PTCL-NOS.

Each of these subtypes may have different causes, signs, symptoms, and outlooks. Knowing the subtype of T-cell lymphoma you have can also help your doctor better understand how to treat your cancer.

Symptoms of T-Cell Lymphoma

Lymphoma symptoms may vary based on the lymphoma subtype, the location where the cancer developed, and the type of lymphocyte involved. Many types of T-cell lymphoma have symptoms such as:

• Fever
• Night sweats
• Backache
• Unintentional weight loss
• Tiredness
• Frequent infections

Many people with T-cell lymphoma also develop swollen lymph nodes. Lymph nodes are small glands that are found throughout the body, including in your head, neck, armpits, and groin.

Lymphoma may also lead to specific symptoms based on which parts of the body are affected. For example, some subtypes of lymphoma are cutaneous, meaning they develop in the skin. These types of lymphoma often lead to rashes and itching.

How Is T-Cell Lymphoma Diagnosed?

If your doctor thinks you may have lymphoma, they will most likely use a variety of tests that help analyze your blood cells. Some of these tests may include:

• A bone marrow or lymph node biopsy, which allows your doctor to look closely at cells under a microscope using a small tissue sample
• A complete blood count (CBC), which analyzes how many of each type of blood cell you have
• A blood smear, which allows your doctor to closely look at cells from your blood under a microscope
• Flow cytometry, which provides information about which type of lymphocyte has become cancerous
• Genetic tests, which might tell which gene mutations can be found in your cancer cells

You may also need to undergo imaging tests — such as a positron emission tomography (PET) or computed tomography (CT) scan —to determine which parts of your body are affected by the lymphoma.

Your doctor will use the information from these test to assign a stage to your lymphoma. T-cell lymphoma subtypes that only affect the lymph nodes have a lower stage (stage 1 or 2) and are generally referred to as nodal lymphomas. Lymphoma that has spread to other parts of the body is given a higher stage (stage 3 or 4) and is often called extranodal lymphoma. Lymphoma stages are sometimes represented with Roman numerals, such as stage IV instead of stage 4.

Lymphoma may also be classified as indolent, meaning it grows slowly, causes few or no symptoms, and is not aggressive. However, these lymphomas tend to respond less to treatment and are more difficult to cure.

What Causes T-Cell Lymphoma?

Lymphomas are caused by genetic mutations that allow cells to divide and grow in a disorganized way. Some of these mutations may be inherited from your parents and are present in all of your cells when you are born. More commonly, gene mutations are acquired, meaning that they occur after birth and affect only certain cells.

It’s not possible to know what exactly causes each case of lymphoma. However, there are certain risk factors that may increase a person’s chance of developing this condition. Risk factors for all types of non-Hodgkin lymphoma include:

• Older age
• Being white
• Being overweight or obese
• Having a family history of lymphoma
• Being exposed to radiation or certain chemicals
• Having had an organ transplantation
• Having a deficient immune system or certain autoimmune diseases

Some specific types of T-cell lymphoma have been linked with viral infections. One subtype, adult T-cell leukemia/lymphoma (ATLL), is caused by human T-cell lymphotropic virus type 1. ATLL is more common in Japan, Africa, and the Caribbean. Another type, angioimmunoblastic T-cell lymphoma, might be caused by a viral infection, such the Epstein-Barr virus.

Treatments for T-Cell Lymphoma

The lymphoma treatment that is best for you will depend on many factors, such as your age, prognosis (outlook), other health conditions, personal preferences, and subtype of T-cell lymphoma. Many times, T-cell lymphomas are treated with a combination of drugs that goes by the acronym CHOP. CHOP stands for:

• Cyclophosphamide (sold as Cytoxan)
• Doxorubicin (also known as hydroxydaunorubicin and sold as Adriamycin)
• Vincristine (formerly sold as Oncovin)
• Prednisone

You may receive all or some of these drugs. Your doctor also may decide that a different set of medications is more likely to work for you based on your individual needs. Other possible treatments might include radiation, surgery, or stem cell transplantation. In an autologous stem cell transplant, your stem cells are removed from your body, aggressively treated, and returned back to your body. You could also receive new, noncancerous stem cells from a healthy donor through what's called an allogeneic stem cell transplant.

Newer treatments are constantly in development. Some newer therapy options include classes of drugs like histone deacetylase inhibitors, proteasome inhibitors, or immunomodulatory drugs. Monoclonal antibodies are another new option. These antibodies can directly bind to and block cancer cells. One example of a drug in this category is Campath (alemtuzumab). Several new drugs are in development, and chimeric antigen receptor (CAR) T-cell therapies are now approved for cancer that has relapsed (returned) or not responded to other treatments.

If you have a cutaneous subtype of lymphoma (one that affects the skin), you may also be prescribed other treatments. These may include:

• Steroids or other topical (applied directly to the skin) medications
• Topical chemotherapy
• Treatments using ultraviolet (UV) light
• Extracorporeal photopheresis, in which your blood is temporarily removed, treated with medication and UV light, and then returned to your body

How well your treatment works depends on many factors, such as your age and lymphoma subtype. For example, if you have a more aggressive disease, it may be less likely to improve. If your initial treatment doesn’t work, your doctor may switch to a different type of treatment. Your doctor may also use a scoring system to calculate how likely your cancer is to respond to treatment or to relapse.

Across all subtypes of T-cell lymphoma, about two-thirds of people will live for at least five years following their diagnosis. However, a person’s individual outlook may be different based on their age and subtype.

Read more about T-cell lymphoma prognosis and outlook.

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