Follicular lymphoma

Follicular lymphoma is confirmed with a biopsy. Most often a surgeon removes a whole lymph node or a piece of one, because a needle sample may be too small to name the exact type. A lab doctor looks at the pattern of the cells. Special stains and a cell-sorting test (flow cytometry) check for B-cell markers.

Gene and chromosome tests, such as FISH, often look for a swap between chromosomes 14 and 18. This swap joins the BCL2 gene to an antibody gene. The U.S. National Cancer Institute (NCI) says a BCL2 rearrangement is found in more than 90% of people with follicular lymphoma. Since 2022, the World Health Organization no longer requires a grade for the common form (classic follicular lymphoma). What used to be called grade 3B is now mostly called follicular large B-cell lymphoma.

The care team then orders staging tests. These often include a PET-CT scan, blood counts and an LDH level, and sometimes a bone marrow biopsy. FISH results usually come back within a couple of days. Full chromosome tests can take a week or more.

Active monitoring is appropriate for selected people without symptoms or a high disease burden. Localized disease may be treated with radiotherapy, sometimes with curative intent. When systemic treatment is needed, options include anti-CD20 antibodies, chemotherapy combinations and targeted medicines.

At relapse, the duration of the previous response, symptoms, biopsy findings and prior treatment guide the next choice. Bispecific antibodies and CAR-T therapy are important options for eligible previously treated patients.

An own-cell (autologous) transplant may be considered after a relapse that responds to treatment. European transplant guidance (EBMT, 2025) says it should be considered for people whose lymphoma came back within 2 years of first chemotherapy with antibody treatment (called POD24), and for people in a second or later remission whose lymphoma has not changed into a faster-growing type. Allogeneic transplantation can provide durable control in selected heavily treated patients, but its risks often make other treatments preferable. Neither transplant is routine for every newly diagnosed patient.

Many people live with follicular lymphoma for many years. Early-stage disease is treated with the goal of cure. Advanced-stage disease is not cured with current treatments, but it usually grows slowly.

Doctors often use a score called FLIPI to describe risk. It counts five things: age over 60, a high LDH level, stage III or IV, a low hemoglobin level, and more than four lymph node areas involved. More factors mean a higher risk. NCI notes that the score cannot tell whether someone needs treatment yet.

Two events shape the outlook most. One is when the lymphoma comes back within 2 years of first chemotherapy with antibody treatment (called POD24). In studies NCI summarizes, about half of those people were alive 5 years later. The other is change into a faster-growing lymphoma. In one large study, this happened in 14% of 2,652 people followed for a median of 6.8 years. U.S. transplant guidance lists both as times to consult a transplant team.