Which stage of Non-Hodgkin lymphoma indicates localized disease?

Stage 1 of Non-Hodgkin lymphoma represents localized disease because it indicates that the cancer is confined to a single lymph node region or a single organ outside of the lymphatic system. This stage is characterized by the absence of widespread involvement, which means that surrounding tissues and other lymph nodes are not affected at this point. In clinical staging for lymphomas, localization is a crucial factor for determining treatment options and prognosis. As the stage progresses to 2, 3, and 4, the involvement becomes more extensive, indicating either multiple regions affected or systemic spread, which significantly influences the management and expected outcomes for the patient.