Canterbury DHB

Diagnosis and Grading

Morphology of the Lymph Node

Morphology still forms the basis of the classification of follicular lymphoma. This is shown in the following table.

Other Laboratory Features

The immunophenotype usually shows surface Ig+, BCL2+, CD10+, CD5^-, CD43^_. The cells express the B cell antigens 19, 20, 22 and 79a. Ig heavy and light chains are rearranged. Most cases of FL have cytogenetic abnormalities; t(14;18) is the commonest at 70-80%. This juxtaposes the BCL-2 gene to the Ig heavy chain gene with resultant over-expression of BCL-2. Other changes include +7 (20%), +18 (20%), 3q 27-28 (15%), 6q 23-26 (15%), 17p (15%). BCL6 may be rearranged.

Management

RCHOP, RBenda, RCVP, Radiation, and Watch and wait are all used depending on circumstances. Autologous transplant as part of second or later line therapy may prolong PFS.

LOW GRADE

• Localised disease Stage I and II: Only 10–15% of follicular lymphoma are detected at the early stages I and II. In these patients radiotherapy is the treatment of choice. This approach results in long-term disease-free survival (DFS) and probable cure in approximately 45–80% of cases.
• Generalised Disease IIB, III, and IV: The remaining patients present with advanced disease which is not curable with conventional therapy. Treatment is usually delayed until the patient is symptomatic ("watch and wait" – see below). Disease control may be achieved with single agent chemotherapy (e.g. chlorambucil) or combined chemotherapy (e.g. CVP or CHOP). Rituximab in combination with chemotherapy has recently been shown to improve DFS and overall survival in advanced follicular lymphoma. Rituximab may be used under Special Authority for the treatment of low grade lymphomas in combination with chemotherapy. The role of transplantation is discussed separately in the Transplant Red Book. Grade 3b follicular lymphoma is usually treated as per diffuse large B-cell lymphoma.
• "Watch and wait": this is the current standard approach for patients with asymptomatic, low-grade non-bulky follicular lymphoma for whom no survival advantage is gained by early chemotherapy. It is recognised that up to a quarter of patients may undergo spontaneous regression and a fifth will not require chemotherapy before 10 years. It is assumed that this approach will lead to an improved quality of life by avoiding the adverse effects of chemotherapy and this is being tested in a randomised, controlled trial.

Further reading

• McNamara C, Montoto S, Eyre TA, et al. The investigation and management of follicular lymphoma. Br J Haematol 2020;191(3):363-381. DOI: 10.1111/bjh.16872.
• Smith S. Transformed lymphoma: what should I do now? Hematology Am Soc Hematol Educ Program 2020;2020(1):306-311. DOI: 10.1182/hematology.2020000115.

Topic Code: 6750