Standardized response criteria are essential for interpretation of clinical data, comparisons among clinical trials, development of new therapies, and approval of agents by regulatory agencies. In 1999, an International Working Group (IWG) developed recommendations for response assessment for non-Hodgkin’s lymphomas (NHL) that were adopted internationally by study groups and regulatory agencies and, subsequently, by clinical trials groups for Hodgkin lymphoma (HL) as well (

Cheson et al,
J Clin Oncol
,
17
:
1244
,
1999
). Since their publication, several observations compelled a reassessment and, ultimately, revision of those guidelines, e.g., the availability of FDG-PET scans, new insights into lymphoma pathology and biology, the failure of the IWG guidelines to include HL and extranodal NHL, and features of the original guidelines that were found to be unclear as they were implemented into clinical trials. Most notable of these was the interpretation of the response category of Complete Remission unconfirmed (CRu). In the context of the IHP, a group of international lymphoma investigators with expertise in medical hematology/oncology, radiation oncology, nuclear medicine and imaging, pathology, biostatistics, and pediatrics were convened to revise the IWG guidelines. Committees focused on Response Criteria, Pathology/Biology, Endpoints, and Clinical Features, and discussions were initiated to undertake a major revision of the IWG guidelines. The important modifications that will be presented included, but were not limited to, integration of PET according to recent data (
Juweid et al,
J Clin Oncol
,
23
:
4652
,
2005
), to facilitate the distinction between persistent tumor and scar/fibrosis, virtually eliminate the designation of CRu, and improve prediction of outcome. Guidelines were provided for the specific indications where this test can be currently recommended. Other proposals involved the role of flow cytometry and assessment of minimal residual disease. Response criteria for extranodal sites were also incorporated. Adoption of these revised guidelines by study groups will further improve the conduct and interpretation of clinical trials leading to more effective therapies for patients with lymphomas.

Topics:
isolated hepatic perfusion, lymphoma, extranodal disease, hodgkin's disease, cicatrix, complete remission, diagnostic imaging, fibrosis, flow cytometry, fluorodeoxyglucose positron emission tomography

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2005, The American Society of Hematology
2005
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