The staging classification used for Hodgkin lymphoma was adopted at the Ann Arbor Conference held in 1971  and revised in 1989.
Subclassification of stage
Hodgkin lymphoma can be subclassified into A and B categories: A is for those patients who are asymptomatic, and B is for those patients with any of the following specific symptoms:
- Unexplained loss of more than 10% of body weight in the 6 months before diagnosis.
- Unexplained fever with temperatures above 38� C for more than 3 days.
- Drenching night sweats.
Extralymphatic disease resulting from direct extension of an involved lymph node region is designated E. Extralymphatic disease can cause confusion in staging. For example, the designation E is not appropriate for cases of widespread disease or diffuse extralymphatic disease (e.g., large pleural effusion that is cytologically positive for Hodgkin lymphoma), which should be considered stage IV. If pathologic proof of noncontiguous involvement of one or more extralymphatic sites has been documented, the symbol for the site of involvement, followed by a plus sign (+), is listed. Current practice is to assign a clinical stage on the basis of findings of the clinical evaluation; however, pathologic confirmation of noncontiguous extralymphatic involvement is strongly suggested for assignment to stage IV.
Involvement of a single lymph node region or, in the case of stage I(E), direct extension from that node to an adjacent extralymphatic region.
Involvement of two or more lymph node regions (number to be stated) on the same side of the diaphragm, or extension from any one of these lymph nodes to an extralymphatic adjacent organ, or stage II(E).
Involvement of lymph node regions on both sides of the diaphragm, which may also be accompanied by extension to an adjacent extralymphatic organ, (stage III[E]), involvement of the spleen (stage III[S+]), or both (stage III[E+S]).
Noncontiguous involvement of one or more extralymphatic organs or tissues with or without associated lymph node involvement.
Early Chemotherapy Response Assessment
Early response assessment can be based on volume reduction of disease, functional imaging status, or both. Significant reduction in disease volume and PET negativity at an early stage (after one or two cycles of chemotherapy) is associated with a favorable outcome. Use of early response assessment to alter therapy remains investigational.
End of Chemotherapy Reevaluation
Restaging is carried out at the end of chemotherapy. The purpose of restaging is to assess the degree of response to initial chemotherapy. Although complete response can be defined as absence of disease by clinical examination and/or imaging studies, complete response in Hodgkin lymphoma trials is often defined by greater than a 70% to 80% reduction of disease and a change from initial positivity to negativity on either gallium or PET scanning. This definition is necessary in Hodgkin lymphoma because fibrotic residual is common, particularly in the mediastinum. In some studies such patients are designated as having an unconfirmed complete response.