Follicular lymphoma (FL, previously called follicle center lymphoma) is the second most common type of non-Hodgkin lymphoma (NHL). It is the most common of the indolent NHLs defined as those lymphomas in which survival of the untreated patient is measured in years. (See "Classification of the hematopoietic neoplasms".)
Treatment of FL depends upon the stage of disease at presentation as evaluated by the Ann Arbor Staging system (table 1). Patients with localized (stage I) disease are candidates for radiation therapy, which is curative in a percentage of patients. In contrast, the treatment of advanced (stage III/IV) disease is not curative and focuses largely on symptom control with chemoimmunotherapy with or without radiation therapy. The management of patients with stage II FL is more variable, with some clinicians offering treatment similar to that used for stage I disease and others offering treatment similar to that used for advanced stage disease. (See "Initial treatment of limited stage (I/II) follicular lymphoma", section on 'Bulky stage II FL'.)
The initial treatment of advanced stage (III/IV) FL is discussed here. The initial treatment of limited stage (I/II) FL and the management of relapsed or refractory FL are presented separately, as are the epidemiology, clinical presentation, pathologic features, diagnosis, and pathobiology of FL. Of importance, the recommendations presented here pertain to patients with histologic grade 1, 2, or 3a FL; patients with grade 3b FL are treated as aggressive lymphomas (eg, diffuse large B cell lymphoma). (See "Initial treatment of limited stage (I/II) follicular lymphoma" and "Treatment of relapsed or refractory follicular lymphoma" and "Clinical manifestations, pathologic features, diagnosis, and prognosis of follicular lymphoma" and "Pathobiology of follicular lymphoma", section on 'Introduction' and "Pathobiology of follicular lymphoma".)
The initial evaluation of a patient with non-Hodgkin lymphoma (NHL) must establish the precise histologic subtype, the extent and sites of disease, and the performance status of the patient. These investigations are important for determining the treatment strategy and for predicting outcome with the Follicular Lymphoma International Prognostic Index (FLIPI) or one of its variants. General approaches to the diagnostic work-up and staging of NHL are presented separately (table 1). The pre-treatment evaluation for patients with advanced stage follicular lymphoma (FL) is the same as that of patients with limited stage FL. This is discussed in more detail separately. (See "Initial treatment of limited stage (I/II) follicular lymphoma", section on 'Pre-treatment evaluation' and "Clinical presentation and diagnosis of non-Hodgkin lymphoma" and "Evaluation and staging of non-Hodgkin lymphoma".)
ADVANCED STAGE DISEASE
Therapeutic strategy — Advanced stage disease includes disease on both sides of the diaphragm (stage III) or diffuse involvement of one or more extralymphatic tissues (stage IV) (table 1). Seventy to 85 percent of patients present with advanced stage disease. Survival rates vary and can be estimated for the population using the Follicular Lymphoma International Prognostic Index (FLIPI) score with five- and 10-year overall survival rates ranging from approximately 50 to 90 and 35 to 70 percent, respectively in the pre-rituximab era (table 2).