Anaplastic large cell lymphoma (ALCL) is classified and staged using several different systems depending on the subtype of ALCL a person has.
The Ann Arbor Staging System
This is the most commonly used system for staging lymphomas. It is used to evaluate the extent of disease in patients with systemic ALCL. It uses Roman numerals I through IV to indicate the extent of the disease.
- Stage I indicates that the cancer is limited to one lymph node region or organ
- Stage II indicates that the cancer is in two or more lymph node regions on the same side of the diaphragm
- Stage III indicates that the cancer is in lymph node regions on both sides of the diaphragm
- Stage IV indicates that the cancer has spread to multiple organs or tissues.
In addition to the stage, the Ann Arbor staging system may include further notations to describe specific situations:
- E (extranodal): This notation is added when the lymphoma involves an extra lymphatic site
- S (splenic): This notation is added when the lymphoma involves the spleen
- B (bulky disease): Bulky disease refers to the presence of a large mass of lymphoma tissue, often defined as a mass with a diameter greater than 10 centimeters
The TNM (Tumor, Node, Metastasis) Staging System
This system is used to stage primary cutaneous ALCL and breast implant-associated ALCL. It describes the extent and spread of the cancer. The TNM staging system includes the following components:
- T Stage (Tumor): The T stage describes the characteristics of the primary skin lesion or tumor. It is further divided into categories based on the size and extent of the tumor:
- T1: Solitary lesion less than or equal to 5 centimeters in diameter
- T2: Solitary lesion more than 5 centimeters in diameter
- T3: Regional disease involving multiple lesions
- T4: Diffuse or disseminated disease involving distant skin sites.
- N Stage (Node): The N stage indicates whether regional lymph nodes are involved:
- N0: No regional lymph node involvement
- N1: Regional lymph node involvement
- M Stage (Metastasis): The M stage indicates whether distant metastasis (spread to distant organs or tissues) is present or absent:
- M0: No distant metastasis
- M1: Distant metastasis
The ALK Gene
In addition to these staging systems, ALCL is also classified based on the presence or absence of a genetic abnormality involving the anaplastic lymphoma kinase (ALK) gene. ALK-positive ALCL is typically associated with a better prognosis than ALK-negative ALCL. The subtype of ALCL is also important for classification. There are three main subtypes: systemic ALCL, primary cutaneous ALCL, and breast implant-associated ALCL. Systemic ALCL can be either ALK-positive or ALK-negative, while primary cutaneous ALCL and breast implant-associated ALCL are typically ALK-negative.
The staging and classification of ALCL are important for determining the appropriate treatment approach and predicting patient prognosis. Treatment options may include chemotherapy, radiation therapy, targeted therapy, and stem cell transplant, depending on the stage and subtype of the disease.