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Staging and grading fNHL
- Staging for fNHL is generally based on the Ann Arbor staging classification (Table 3)
- This staging system was originally proposed for Hodgkin's lymphoma and has been routinely applied to NHL14
- It is primarily based on the distribution of lymphatic involvement with respect to the diaphragm and the presence of extralymphatic organ involvement14
- The Ann Arbor system does not reflect the extent of disease spread in NHL nor does it discriminate between stage III and IV intermediate-grade disease. The classification also fails to account for tumor bulk or the number of extranodal sites14
Table 3. Ann Arbor staging system.14,19
WHO classification of histological grades
- Use of a grading system divides patients into subgroups and influences both the timing of therapy as well as treatment decisions5,20
- The WHO classification of fNHL recommends that grading be carried out according to the counting method proposed by Mann and Berard to define 3 grades20 (Table 4)
- This system describes 3 grades (grades 1 to 3) based on the absolute number of centroblasts (large or small) per 40x high-power field4,20
- The vast majority (80% to 90%) of fNHLs are grades 1 to 220
- A classification of fNHL grade 3 suggests that the patient is at high-risk for disease progression20
- fNHL grade 3 is divided into grades 3A and 3B based on the presence of centrocytes20
- fNHL grade 3B is commonly treated according to DLBCL treatment guidelines. For more information, please refer to the Transformed fNHL section under DLBCL13
