How Doctors Grade Follicular Lymphoma
A cancer grade measures how quickly a cancer is predicted to progress. Doctors typically divide follicular lymphoma into grades 1 to 3 depending on how the cancer cells look under a microscope.
Follicular lymphoma makes up about 30% of all non-Hodgkin’s lymphomas. It develops in B cells, which are a type of white blood cell that produces antibodies.
The outlook for people with follicular lymphoma is usually good since it typically develops slowly, although some follicular lymphomas are more aggressive than others.
People with follicular lymphoma live at least 5 years after diagnosis about 90% as often as people without cancer.
In this article, we look at how doctors determine grades for follicular lymphoma and how these grades influence treatment.
The World Health Organization (WHO) grading system divides follicular lymphoma into grades 1 to 3 depending on how a sample of cancer cells looks under a microscope. This grading system is based on how many enlarged B cells, called centroblasts, are seen.
Research suggests that having more of these large cells is associated with faster cancer progression and a higher chance your lymphoma will progress into a more aggressive type of non-Hodgkin’s lymphoma called diffuse large B-cell lymphoma.
About 25% to 35% of follicular lymphoma cases progress to this type of lymphoma.
Grade 1 follicular lymphoma is the least aggressive type. It’s also called follicular small cleaved cell lymphoma .
Doctors diagnose grade 1 follicular lymphoma if they see 0 to 5 centroblasts per high power field (HPF). An HPF is usually defined as the area doctors can see under a microscope at 400 times magnification.
Grades 1 and 2 follicular lymphoma are considered slow growing. They are generally treated the same way.
Radiation therapy is the primary treatment for lymphoma isolated to one part of your body. Doctors generally use a type of immunotherapy called anti-CD20 antibodies combined with chemotherapy for advanced and symptomatic follicular lymphoma.
Grade 2 follicular lymphoma is also called follicular mixed-cell lymphoma. It’s defined as follicular lymphoma with 6 to 15 centroblasts per HPF.
Treatment for grade 2 follicular lymphoma is generally the same as grade 1.
Doctors diagnose grade 3 follicular lymphoma, or follicular large cell lymphoma, if they see more than 15 centroblasts per HPF.
The WHO divides grade 3 follicular cancer into two subcategories depending on its features:
Grade 3A
The WHO classifies follicular lymphoma as grade 3A if there are centrocytes present in your cancer sample. Centrocytes are small- to medium-sized B cells that have a cleaved nucleus . A cleaved nucleus is a cell that looks divided under a microscope. It occurs with certain types of lymphomas.
R-CHOP chemotherapy usually treats grade 3A follicular lymphomas if there are aggressive clinical features present, such as:
- lymph nodes enlarging over weeks to months
- systemic B symptoms , such as:
- fever
- weight loss
- drenching night sweats
Treatments for grade 3A follicular lymphomas without aggressive clinical features typically involve radiation of localized disease for stage 1 and rituximab (Rituxan) with or without bendamustine (Treanda) chemotherapy for stages 2 through 4.
These treatments help relieve symptoms associated with low blood counts.
Grade 3B
Doctors diagnose grade 3B follicular lymphoma if the cancer sample looks like a solid sheet of centroblasts.
Research suggests that grade 3B follicular lymphoma follows an aggressive course like diffuse large B cell lymphoma.
Doctors usually treat people with grade 3B follicular lymphoma with aggressive chemotherapy regimens, such as R-CHOP.
Is grade 3 follicular lymphoma curable?
Follicular lymphoma is not usually curable. However, treatment can help slow its progression and reduce your symptoms.
A 2022 study found that chemotherapy can sometimes cure follicular lymphoma.