How Is T-Cell Lymphoma Staged And Classified?

T-cell Lymphoma is staged and classified using the Ann Arbor staging system, which is the most commonly used system for lymphomas. This system classifies the disease into four stages (I-IV) based on the number of lymph nodes involved and the parts of the body affected. The stages are further divided into A and B categories, where 'A' indicates absence of symptoms like fever, weight loss, and night sweats, and 'B' indicates their presence.

Classification of T-Cell Lymphoma

T-cell lymphomas are classified based on their cell of origin, the appearance of the cells under a microscope, and the presence of certain proteins on the cell surface. The World Health Organization (WHO) has classified T-cell lymphomas into several types, including Peripheral T-cell lymphoma (PTCL), Anaplastic large cell lymphoma (ALCL), and Cutaneous T-cell lymphoma (CTCL). Each type has a different prognosis and treatment approach.

Phases of T-Cell Lymphoma

The phases of T-cell lymphoma are typically referred to as stages. Here is a brief overview of the stages:

• Stage I: The cancer is found in one lymph node region or one organ outside the lymph nodes.
• Stage II: The cancer is found in two or more lymph node regions on the same side of the diaphragm, or it extends from a single lymph node region into a nearby organ.
• Stage III: The cancer is found in lymph node regions on both sides of the diaphragm.
• Stage IV: The cancer has spread widely into multiple organs outside the lymphatic system.

T-cell lymphomas are a diverse group of cancers that develop from T-cells, a type of white blood cell responsible for protecting the body against infections. These lymphomas fall under the broader category of non-Hodgkin lymphomas and can be challenging to diagnose and treat due to their complex nature. In this article, you will learn the different types of T-cell lymphomas, how they are classified, and the significance of staging in managing this condition.

What are the Types of T-cell Lymphoma?

The World Health Organization (WHO) divides T-cell lymphomas into different groups based on their origin and behavior, including precursor T-cell lymphoma, natural killer (NK) cell lymphoma, and mature T-cell lymphoma.  Each type presents unique characteristics, influencing how doctors approach treatment. 

1. Precursor T-cell lymphoma: non-Hodgkin lymphoma in which too many T-cell lymphoblasts (immature white blood cells) are found in the lymph nodes and spleen.
2. NK-cell lymphoma: short for natural killer T-cell lymphoma (NKTL), is a subtype of Epstein–Barr virus (EBV)- related non-Hodgkin lymphomas that are common in Asia and Latin America but rare elsewhere.
3. Mature T-cell lymphoma: this is a rare group of diverse and typically aggressive abnormal T-cell overgrowth 

The mature T-cell lymphomas are further divided into four groups:

• Leukemic (in the blood)
• Nodal (in the lymph nodes)
• Extranodal (outside the lymph nodes, such as in organs)
• Cutaneous (in the skin)

Other types of T-cell lymphomas include:

• Mycosis fungoides (MF) and Sézary syndrome (SS): These are the main types of cutaneous T-cell lymphoma, affect the skin and cause skin lesions 
• Peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS): The most common peripheral T-cell lymphoma type.
• Anaplastic large cell lymphoma (ALCL) and Angioimmunoblastic T-cell lymphoma (AITL).

How is T-Cell Lymphoma Staged?

The Lugano classification is a staging system used for all lymphoma types, including Hodgkin lymphoma and non-Hodgkin lymphoma. It is divided into limited vs. advanced, depending on the location and number of affected lymph nodes.  

Limited

• I: Involvement: One node or a group of adjacent nodes.  Extranodal status: Single extranodal lesions without nodal involvement.

• II: Involvement: Two or more nodal groups on the same side of the diaphragm. Extranodal status: Stage I or II by nodal extent with limited contiguous extranodal involvement.

Advanced

• III: Involvement: Nodes on both sides of the diaphragm; nodes above the diaphragm with spleen involvement.

• IV: Involvement: Additional noncontiguous extra lymphatic involvement.

Does T-Cell Lymphoma Have Phases? 

The phases of T-cell lymphoma are typically referred to as stages, which helps doctors understand the extent of the lymphoma and the best treatment strategy at the moment of diagnosis. 

• Stage I: The cancer is found in one lymph node region or one organ outside the lymph nodes.
• Stage II: The cancer is found in two or more lymph node regions on the same side of the diaphragm, or it extends from a single lymph node region into a nearby organ.
• Stage III: The cancer is found in lymph node regions on both sides of the diaphragm.
• Stage IV: The cancer has spread widely into multiple organs outside the lymphatic system.

Each stage can also be sub-classified depending on the symptoms and organs it is affecting, this gives a letter that indicates which symptom or organ a patient presents, for example:

• A: asymptomatic (no symptoms)
• B: presence of B symptoms (including fever, night sweats and weight loss of ≥10% of body weight over 6 months)
• E: extranodal site (outside the lymph nodes), close or next to a known lymph node (stages I to III only for one extranodal site; more than two sites is stage IV)
• S: there is spleen involvement
• X: bulky nodal disease: nodal mass >1/3 of intrathoracic diameter or 10 cm in dimension

With the aid of staging systems, doctors can tailor treatment plans to each patient's needs, based on the lymphoma extent at the moment of diagnosis, as well as following up during and after treatment. Despite the aggressive nature of some T-cell lymphomas, understanding how they develop and where they tend to be located is improving patient outcomes. By staying informed about the types and stages of T-cell lymphoma, patients and their loved ones can play an active role in the treatment process and make empowered decisions.

To learn more about signs and symptoms of T-cell lymphoma, you can visit our comprehensive 101 pages. 

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Sources:

• https://www.ncbi.nlm.nih.gov/books/NBK564354/
• https://seer.cancer.gov/seerstat/variables/seer/ajcc-stage/ann-arbor/