Targeted Oncology
Targeted Oncology
Targeted Oncology

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How to Refine Treatment Choice in Follicular Lymphoma

Peter A. Riedell, MD and Brad S. Kahl, MD
Published Online: Mar 08,2017

From Low-Tumor Burden to High-Risk Follicular Lymphoma

Abstract

Follicular lymphoma (FL) is the most common subtype of indolent non-Hodgkin lymphoma in the Western world and has an excellent prognosis with current therapies. Management of FL has traditionally included a watch-and-wait approach or chemotherapy. In the past decade, this treatment paradigm has been challenged with the introduction of the anti-CD20 monoclonal antibody rituximab. In FL, numerous treatment options exist, making therapeutic decision-making challenging. Furthermore, given the disease heterogeneity, there is no standard front-line approach. When making therapeutic decisions in FL, it is crucial for practitioners to assess a number of patient-specific factors including age, disease burden, comorbidities, and coping style. In this review, we examine the various front-line treatment options in FL and outline an algorithm for approaching patients with newly diagnosed FL.


Introduction

Follicular lymphoma (FL) is the most common subtype of indolent non-Hodgkin lymphoma (NHL) in the Western Hemisphere.1 With current therapy options, prognosis is favorable, with median overall survival (OS) exceeding 12 years.2 Recent advances in disease management and our understanding of the biology of FL have led to a dramatic change in the treatment landscape. Despite this progress, FL remains incurable with standard therapies. Therefore, it is critical to design treatment strategies focused on controlling symptoms while considering such factors as age, comorbidities, patient preference, and disease-specific risk factors. Herein, we briefly review the evolving treatment strategies in FL.
 

Assigning Risk in FL

FL is a heterogeneous disease with varying prognosis based on a combination of clinical, laboratory, and disease parameters.

The following metrics have been developed to help guide therapeutic decision-making and determine appropriate candidates for a watch-and-wait (W/W) approach, single agent rituximab, or combination immunochemotherapy.
 

Tumor Grade

Tumor grade is used to classify FL based on the number of centroblasts per high-power field (HPF). In general, cases harboring a greater number of centroblasts behave more aggressively and are associated with a higher risk of transformation to diffuse large B cell lymphoma (DLBCL). Grade 1 (<5 centroblasts/ HPF) and grade 2 (6-15 centroblasts/HPF) FL are combined in the WHO classification given their similar clinical behavior.3 Grade 3 FL can be further subdivided into 3A and 3B, with the latter distinguished by a lack of centrocytes. Despite a higher tumor grade, FL grade 3A behaves like grade 1-2 FL and as such should be approached in a similar fashion.4 FL grade 3B represents a distinct entity characterized by a diffuse architectural pattern, frequent loss of CD10 expression, and absence of t(14;18). Consequently, its clinical course and treatment mirror that of DLBCL.4,5
 

Prognostic Index


 

The Follicular Lymphoma International Prognostic Index (FLIPI) was derived from a cohort of greater than 4000 FL patients diagnosed in the pre-rituximab era and is used to predict OS. The index, as outlined in Table 1, stratifies patients into three risk groups, low-risk (0-1 factors), intermediate risk (2 factors), and high risk (≥3 factors) with 10-year OS rates of 71%, 51%, and 36%, respectively. Similarly, the FLIPI-2 score was developed to predict progression-free survival (PFS) in the rituximab era and incorporates five clinical and laboratory parameters including β2-microglobulin.6 Though these scoring systems aid in determining long-term prognosis, neither provides guidance regarding when to initiate therapy.




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How to Refine Treatment Choice in Follicular Lymphoma
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