Extranodal natural killer (NK)/T-cell lymphoma is a rare and aggressive form of non-Hodgkin lymphoma. Staging and classification of this disease is crucial for determining the appropriate treatment and predicting prognosis. The Ann Arbor staging system, with Cotswolds modifications, is commonly used to stage this disease. This system classifies the disease into four stages (I-IV) based on the extent of the disease and the involvement of lymph nodes and other organs.
Understanding the Ann Arbor Staging System
The Ann Arbor staging system classifies the disease as follows:
- Stage I: The cancer is limited to one lymphatic site (extranodal) or to one lymph node region (nodal).
- Stage II: The cancer is in two or more lymph node regions on the same side of the diaphragm or extends locally from one lymph node region into an organ.
- Stage III: The cancer is in lymph node regions on both sides of the diaphragm.
- Stage IV: The cancer has spread widely into multiple organs outside the lymphatic system.
Classification of Extranodal Natural Killer
Extranodal NK/T-cell lymphoma is classified based on the cell type and the location of the disease. The World Health Organization (WHO) classifies this disease into two types: nasal type and non-nasal type. The nasal type is the most common and it originates in the nasal cavity. The non-nasal type can occur in any part of the body outside the nasal cavity.
Phases of Extranodal Natural Killer
The phases of extranodal natural killer (NK)/T-cell lymphoma are not typically referred to as 'phases'. Instead, the progression of the disease is described in terms of stages, as outlined above. The disease may progress from a localized stage (stage I) to a more advanced stage (stage IV) where it has spread to other parts of the body. The speed and pattern of this progression can vary greatly from patient to patient.