Clinical significance of the WHO grades of follicular lymphoma in a population-based cohort of 505 patients with long follow-up times

The value of semiquantitative PET features and end-of-therapy PET in grade 3B follicular lymphoma

Grade 3B follicular lymphoma (G3BFL) is a rare lymphoma thought to sit on a continuum between low-grade FL and diffuse large B-cell lymphoma (DLBCL). The prognostic impact of quantitative positron emission tomography (PET) metrics such as total metabolic tumour volume (TMTV), total lesion glycolysis (TLG), and maximum standard uptake value (SUVmax) have been extensively analysed in FL and DLBCL, but G3BFL data are lacking. Here, we describe PET outcomes and radiomic characteristics in 46 G3BFL cases uniformly treated with R-CHOP (like) chemotherapy. Central semi-automated PET TMTV, TLG, and SUVmax analyses, using MIM software, were correlated with clinical outcomes and compared with published results in low-grade FL and DLBCL. In G3BFL, the end-of-treatment complete metabolic response was associated with improved progression-free survival (PFS; p = 0.002) and overall survival (OS; p = 0.04). G3BFL median TLG (1455) and SUVmax (16.50) sit between published values for low-grade FL (TLG: 1112, SUVmax: 11.3) and DLBCL (TLG: 3004, SUVmax: 24.35). No association between TMTV (>350 cm3) and survival was seen (PFS: p = 0.24; OS: p = 0.40). High SUVmax (>19.2) and TLG (>2760) both conferred inferior PFS but not OS (PFS: SUVmax p = 0.004; TLG p = 0.05). These data support the routine incorporation of PET radiomics at baseline and treatment response for G3BFL.

B-cell non-Hodgkin lymphomas

B-cell lymphomas occur with an incidence of 20 new cases per 100 000 people per year in high-income countries. They can affect any organ and are characterised by heterogeneous clinical presentations and courses, varying from asymptomatic, to indolent, to very aggressive cases. Since the topic of B-cell non-Hodgkin lymphomas was last reviewed in The Lancet in 2017, a deeper understanding of the biological background of this heterogeneous group of malignancies, the availability of new diagnostic methods, and the development and implementation of new targeted and immunotherapeutic approaches have improved our ability to treat patients. This Seminar provides an overview of the pathobiology, classification, and prognostication of B-cell non-Hodgkin lymphomas and summarises the current knowledge and standard of care regarding biology and clinical management of the most common subtypes of mature B-cell non-Hodgkin lymphomas. It also highlights new findings in deciphering the molecular background of disease development and the implementation of new therapeutic approaches, particularly those targeting the immune system.

[New classifications of malignant lymphomas - What changes are relevant for practice?]

An internationally uniform lymphoma classification is of fundamental importance for the comparability of clinical studies. There are currently 2 parallel classifications: the "International Consensus Classification" and the WHO-classification. Follicular lymphoma 3B is classified separately as follicular large cell lymphoma in WHO-HAEM5. The diagnostic criteria of lymphoplasmocytic lymphoma (LPL) have been adjusted, both classifications recommend molecular testing for MYD88 and CXCR4 mutations. There are no significant diagnostic changes in aggressive B-cell lymphomas. The ICC classify NLPBL and THRLBCL into the group of large B-cell lymphomas (LBCL). NLPHL/NLPBL-specific therapy must be considered, which differs greatly from the therapy of DLBCL, especially in the early stages. Peripheral T-cell lymphomas are a group of nodal T-cell lymphomas with a TFH phenotype and frequent mutations; peripheral T-cell lymphoma (NOS) is therefore a diagnosis of exclusion. Indolent T-cell lymphomas/lymphoproliferations of the GI tract are rare but must be differentiated from aggressive T-cell lymphomas. The WHO-HAEM5 also includes reactive/non-neoplastic lymph node lesions classified according to B or T cell predominance.

Fifth Edition of the World Health Classification of Tumors of the Hematopoietic and Lymphoid Tissues: B-cell Neoplasms

We review B-cell neoplasms in the 5th edition of the World Health Organization classification of hematolymphoid tumors (WHO-HEM5). The revised classification is based on a multidisciplinary approach including input from pathologists, clinicians, and other experts. The WHO-HEM5 follows a hierarchical structure allowing the use of family (class)-level definitions when defining diagnostic criteria are partially met or a complete investigational workup is not possible. Disease types and subtypes have expanded compared with the WHO revised 4th edition (WHO-HEM4R), mainly because of the expansion in genomic knowledge of these diseases. In this review, we focus on highlighting changes and updates in the classification of B-cell lymphomas, providing a comparison with WHO-HEM4R, and offering guidance on how the new classification can be applied to the diagnosis of B-cell lymphomas in routine practice.

The pathobiology of follicular lymphoma

Follicular lymphoma is one of the most frequent lymphomas. Histologically, it is characterized by a follicular (nodular) growth pattern of centrocytes and centroblasts; mixed with variable immune microenvironment cells. Clinically, it is characterized by diffuse lymphadenopathy, bone marrow involvement, and splenomegaly. It is biologically and clinically heterogeneous. In most patients it is indolent, but others have a more aggressive evolution with relapses; and transformation to diffuse large B-cell lymphoma. Tumorigenesis includes an asymptomatic preclinical phase in which premalignant B-lymphocytes with the t(14;18) chromosomal translocation acquire additional genetic alterations in the germinal centers, and clonal evolution occurs, although not all the cells progress to the tumor stage. This manuscript reviews the pathobiology and clinicopathological characteristics of follicular lymphoma. It includes a description of the physiology of the germinal center, the genetic alterations of BCL2 and BCL6, the mutational profile, the immune checkpoint, precision medicine, and highlights in the lymphoma classification. In addition, a comment and review on artificial intelligence and machine (deep) learning are made.

Pretreatment CT Texture Parameters as Predictive Biomarkers of Progression-Free Survival in Follicular Lymphoma Treated with Immunochemotherapy and Rituximab Maintenance

The purpose of this study was to determine whether texture analysis features present on pretreatment unenhanced computed tomography (CT) images, derived from 18F-fluorodeoxyglucose positron emission/computed tomography (18-FDG PET/CT), can predict progression-free survival (PFS), progression-free survival at 24 months (PFS 24), time to next treatment (TTNT), and overall survival in patients with high-tumor-burden follicular lymphoma treated with immunochemotherapy and rituximab maintenance. Seventy-two patients with follicular lymphoma were retrospectively included. Texture analysis was performed on unenhanced CT images extracted from 18-FDG PET/CT examinations that were obtained within one month before treatment. Skewness at a fine texture scale (SSF = 2) was an independent predictor of PFS (hazard ratio = 3.72 (95% CI: 1.15, 12.11), p = 0.028), PFS 24 (hazard ratio = 13.38; 95% CI: 1.29, 138.13; p = 0.029), and TTNT (hazard ratio = 5.11; 95% CI: 1.18, 22.13; p = 0.029). Skewness values above -0.015 at SSF = 2 were significantly associated with lower PFS, PFS 24, and TTNT. Kurtosis without filtration was an independent predictor of PFS (SSF = 0; HR = 1.22 (95% CI: 1.04, 1.44), p = 0.013), and TTNT (SSF = 0; hazard ratio = 1.23; 95% CI: 1.04, 1.46; p = 0.013). This study shows that pretreatment unenhanced CT texture analysis-derived tumor skewness and kurtosis may be used as predictive biomarkers of PFS and TTNT in patients with high-tumor-burden follicular lymphoma treated with immunochemotherapy and rituximab maintenance.

Differences in clinical characteristics and outcomes between patients with grade 3a and grades 1-2 follicular lymphoma: a real-world multicenter study

BACKGROUND

The difference between clinical characteristics and outcomes between follicular lymphoma grade 1-2 (FL1-2) and FL3a defined pathologically remains unclear, resulting in uncertainty how to treat FL3a. However, it may be crucial for clinicians to discriminate grade 3a and grade 1-2 for predicting prognosis and thus making treatment decisions.

METHODS

We compared 1403 patients with FL1-2 and 765 patients with FL3a diagnosed between January 2000 and December 2020 from fifteen centers nationwide in China to describe differences in clinical characteristics and outcomes.

RESULTS

Compared with FL1-2 patients, FL3a subgroup had a higher percentage of elderly patients (P = 0.003), and relatively more FL3a patients presented with increased levels of LDH (P < 0.0001) and higher Ki-67 indexs greater than 30% (P < 0.001). More FL3a patients were treated with CHOP ± R (P < 0.0001), and fewer were treated with the watchful-waiting approach (P < 0.0001). The results showed a higher incidence of relapse among FL3a patients, in which more patients underwent histological transformation (HT) when compared to FL1-2 (P = 0.003). 1470 (76.2%) patients of the entire cohort received R-CHOP therapy; survival analysis revealed that FL3a patients had a worse progression-free survival (PFS) rate than FL1-2 patients. Survival of FL3a patients with respect to FLIPI showed an inferior PFS in the intermediate and high-risk groups than FL1-2 patients. FL3a patients had a much worse prognosis than FL1-2 with or without progression of disease within 24 months (POD24). FL3a patients had higher likelihood of lymphoma-related death (LRD, P < 0.05), whereas the rates for non-LRD were comparable.

CONCLUSION

In conclusion, this study demonstrates a marked difference in clinical features and outcomes in FL3a patients compared with FL1-2 patients. The results highlight the need for applying therapeutic approaches distinct from FL1-2 when treating FL3a patients.

Core Needle Biopsy in Lymphoma Diagnosis: The Diagnostic Performance and the Role of the Multidisciplinary Approach in the Optimization of Results

To compare the diagnostic accuracy of core needle biopsies (CNBs) and surgical excisional biopsies (SEBs), samples of lymphoid proliferation from a single institution from 2013 to 2017 (N=476) were divided into groups of CNB (N=218) and SEB (N=258). The diagnostic accuracy of these samples was evaluated as a percentage of conclusive diagnosis, according to the World Health Organization Classification of Tumours of Haematopoietic and Lymphoid Tissues . The contribution of clinical data, the assessment of sample adequacy by a pathologist during the procedure, the number and size of fragments, the needle gauge, the ancillary tests, and the type of lymphoid proliferation were also examined. The diagnostic accuracy of SEB was 97.3% and CNB 91.3% ( P =0.010). Additional factors considered essential for establishing the final diagnosis in some cases were: clinical information (20.6% CNB, 7.4% SEB; P <0.001); immunohistochemistry (96.3% CNB, 91.5% SEB; P =0.024); flow cytometry (12% CNB, 6.8% SEB; P =0.165); and other complementary tests (8.2% CNB, 17.3% SEB; P =0.058). Factors that did not influence performance were the evaluation of sample adequacy during the procedure, the number and size of fragments, and the needle gauge. Increased percentage of nondiagnostic CNB was observed in T-cell lymphomas (30%), followed by classic Hodgkin lymphoma (10.6%). The main limitation of CNB was the evaluation of morphologically heterogenous diseases. CNB is useful and safe in lymphoma diagnosis provided it is carried out by a team of experienced professionals. Having an interventional radiology team engaged with pathology is an essential component to achieve adequate rates of specific diagnoses in CNB specimens.

Follicular lymphoma: 2023 update on diagnosis and management

DISEASE OVERVIEW

Follicular lymphoma (FL) is generally an indolent B cell lymphoproliferative disorder of transformed follicular center B cells. FL is characterized by diffuse lymphadenopathy, bone marrow involvement, and splenomegaly. Extranodal involvement is less common. Cytopenias are relatively common but constitutional symptoms of fever, night sweats, and weight loss are uncommon in the absence of transformation to diffuse large B cell lymphoma.

DIAGNOSIS

The diagnosis is based on histology from a biopsy of a lymph node or other affected tissue. Incisional biopsy is preferred over needle biopsies in order to give adequate tissue to assign grade and assess for transformation. Immunohistochemical staining is positive in virtually all cases for cell surface CD19, CD20, CD10, and monoclonal immunoglobulin, as well as cytoplasmic expression of bcl-2 protein. The overwhelming majority of cases have the characteristic t(14;18) translocation involving the IgH/bcl-2 genes.

RISK STRATIFICATION

The Follicular Lymphoma International Prognostic Index (FLIPI) uses five independent predictors of inferior survival: age >60 years, hemoglobin <12 g/dL, serum LDH > normal, Ann Arbor stage III/IV, number of involved nodal areas >4. The presence of 0-1, 2, and ≥3 adverse factors defines low, intermediate, and high-risk disease. There are other clinical prognostic models but the FLIPI remains the most common. Other factors such as time to relapse of less than 2 years from chemoimmunotherapy and specific gene mutations may also be useful for prognosis. Regardless of the prognostic model used, modern therapies have demonstrably improved prognosis.

RISK-ADAPTED THERAPY

Observation continues to be appropriate for asymptomatic patients with low bulk disease and no cytopenias. There is no overall survival (OS) advantage for early treatment with either chemotherapy or single-agent rituximab. For patients needing therapy, most patients are treated with chemoimmunotherapy, which has improved overall response rates (ORR), DOR, and OS. Randomized studies have shown additional benefits for maintenance of rituximab. Lenalidomide was non-inferior to chemoimmunotherapy in a randomized front-line study and, when combined with rituximab, was superior to rituximab alone in relapsed FL. Kinase inhibitors, stem cell transplantation (SCT), and chimeric antigen receptor T cells (CAR-T) are also considered for recurrent disease.

The impact of histological grade on outcomes in follicular lymphoma: An analysis of patients in the SEER database in the context of evolving disease classification and treatment

Currently, there is no convincing evidence that the grade of follicular lymphoma (FL) impacts patient outcome. We correlated grades in 33 925 patients with nodal FL during 1992-2018 in the SEER database with disease-specific survival (DSS) and overall survival (OS). Patients with FL grade 3 had lower DSS and OS as compared to FL grades 1-2. During 1992-2005, the 10-year DSS for patients with FL grades 3 and grades 1-2 were 68.6%, and 71.4%, respectively, and in 2006-2018, they were 77.7% and 82.6%, respectively. The 10-year OS estimates in 1992-2005 were 49.9% and 54.2% for grade 3 and grades 1-2 respectively, and in 2006-2018, they were 59.1% and 63.5% for grade 3 and grades 1-2, respectively. After adjustment for stage and age, the hazard ratios for death due to FL and death from any cause for patients with FL grade 3 during 1992-2005 were 1.09 (1.02-1.16) and 1.07 (1.02-1.12), respectively, compared to FL grades 1-2; and during 2006-2018, the hazard ratios for death due to FL and death from any cause for patients with FL grade 3 were 1.34 (1.22-1.45) and 1.16 (1.10-1.23), respectively compared to FL grades 1-2. The grade of FL is an important determinant of disease biology.

Clinical characteristics and prognosis of patients with co-existing follicular lymphoma and diffuse large B-cell lymphoma components in rituximab era

PURPOSE

This single-centre study aimed to determine the clinicopathological characteristics and prognosis for patients with co-existing FL and DLBCL components (FL/DLBCL).

METHODS

We retrospectively analysed the clinical characteristics and prognosis of patients diagnosed with FL/DLBCL (n = 56) and with pure FL (n = 260) or de novo DLBCL (n = 812) (controls) between January 2013 and December 2021.

RESULTS

The median age of patients with FL/DLBCL was 52 years. The amount of the DLBCL component ranged from 5 to 95%. Among the 56 FL/DLBCL cases analysed, 67.9% were of germinal centre B-cell (GCB) origin, 26.8% non-GCB origin, and 5.3% were unclassified. The clinical features of patients with FL/DLBCL were intermediate, falling between those of FL and DLBCL. Propensity-score matching was performed for patients with similar baseline characteristics who were receiving the rituximab plus cyclophosphamide, doxorubicin or epirubicin, vindesine, and prednisone (R-CHOP) regimen. Patients with FL/DLBCL showed inferior outcomes compared to those with FL, with a lower complete remission (CR) rate, progression-free survival (PFS), and overall survival (OS). Bone marrow involvement and B symptoms were identified as independent adverse prognostic factors for PFS among patients with FL/DLBCL. Patients with FL/DLBCL presented a lower CR rate and PFS but similar OS to those with DLBCL when receiving the R-CHOP regimen.

CONCLUSION

Patients with FL/DLBCL showed inferior treatment response and survival than those with pure FL and had a lower CR rate and PFS, but similar OS to those with DLBCL in the rituximab era.

Clinical features and outcomes of patients with follicular lymphoma: A real-world study of 926 patients in China

Background

The data about the clinical features and outcomes of Chinese patients with follicular lymphoma (FL) are limited. Here, we conducted a retrospective study to explore the initial treatment strategies and clinical outcomes of Chinese patients with FL in the real world.

Method

This study included FL patients who were newly diagnosed in Tianjin Medical University Cancer Institute and Hospital from March 2002 to August 2020.

Results

A total of 926 FL patients were enrolled. The median age was 54 years old, and the majority of the Chinese FL patients had advanced-stage disease and Eastern Cooperative Oncology Group(ECOG) <1 but less frequently infiltrated bone marrow. After a median of 38-month follow-up, the 5-year progressive-free survival (PFS) and overall survival (OS) of grade1-3a were 57.8% and 88.7%, respectively, which both are similar to those reported in previous Chinese and Western studies. The co-existence at diagnosis of FL and diffuse large B-cell lymphoma (DLBCL) components (FL/DLBCL) was associated with poor outcomes. The FL grades and proportion of DLBCL component in FL/DLBCL did not have an impact on PFS and OS. The most common regimen with great efficacy and risk-benefit was RCHOP-like followed by R maintenance regimen. The 5-year cumulative hazard of histological transformation (HT) was 4.7% (95% CI, 3.5-5.9); median time to transformation was 23.5 months (range, 2-146 months) after diagnosis. Three-year survival following transformation was 55% (95% CI, 40-70). Patients with stage III-IV, elevated β2 microglobulin (β2-MG), and B symptoms seemed to be more prone to progress within 24 months of frontline therapy (POD24). The FLIPI-2 showed the highest specificity to predict POD24, reflecting the prediction of correctly classifying as low-risk patients, but the FLIPI had the highest sensitivity to predict the risk of progression for critical patients.

Conclusions

We revealed the clinical characteristics and outcomes of FL patients in the real world in China, which may provide novel data on prognostic factors and primary treatment of FL, applicable to routine clinical practice.

Serum high-density lipoprotein cholesterol level has a significant prognostic impact on outcomes of follicular lymphoma patients

We investigated the potential of nutritional and inflammatory parameters as prognostic factors for follicular lymphoma (FL), and also examined the predictive value of the early progression of disease within 24 months of first-line chemo-immunotherapy (POD24). We retrospectively analyzed 46 patients with FL admitted to Teikyo University Hospital and treated with chemo-immunotherapy between May 2009 and July 2019. Physical characteristics, blood parameters, and markers or scores for consumptive/inflammatory and nutritional conditions were used as variables. Nine parameters correlated with poor overall survival (OS) in univariate analysis: An Eastern Cooperative Oncology Group (ECOG) scale performance status (PS) ≥2, five or more involved nodal sites, positive bone marrow (BM) involvement, a serum albumin level <3.5 g/dL, CRP >0.5 mg/dL, lactate dehydrogenase (LD) higher than the upper normal limit (UNL), high-density lipoprotein cholesterol (HDL-C) <40 mg/dL, modified Glasgow prognostic score of 1-2, and the geriatric nutritional risk index <82. In multivariate analysis, ECOG PS ≥2, positive BM involvement, and a serum HDL-C level <40 mg/dL remained significant for poor progression-free survival. One-year OS rate after receiving salvage chemotherapy was lower in the POD24 group (50%) and POD24 correlated with ECOG PS ≥2, positive BM involvement, a serum lactate dehydrogenase >UNL, and HDL-C <40 mg/dL by Fisher's exact test. These results indicate that low serum HDL-C levels appear to be important for predicting the risk of POD24 and the worse prognosis of FL.

The 5th edition of the World Health Organization Classification of Haematolymphoid Tumours: Lymphoid Neoplasms

We herein present an overview of the upcoming 5^th edition of the World Health Organization Classification of Haematolymphoid Tumours focussing on lymphoid neoplasms. Myeloid and histiocytic neoplasms will be presented in a separate accompanying article. Besides listing the entities of the classification, we highlight and explain changes from the revised 4^th edition. These include reorganization of entities by a hierarchical system as is adopted throughout the 5^th edition of the WHO classification of tumours of all organ systems, modification of nomenclature for some entities, revision of diagnostic criteria or subtypes, deletion of certain entities, and introduction of new entities, as well as inclusion of tumour-like lesions, mesenchymal lesions specific to lymph node and spleen, and germline predisposition syndromes associated with the lymphoid neoplasms.

Screening of Adverse Prognostic Factors and Construction of Prognostic Index in Previously Untreated Concurrent Follicular Lymphoma and Diffuse Large B-Cell Lymphoma

Objective

Concurrent follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL) (defined as FL/DLBCL) have been considered an important pathological feature in cell lymphoma. However, clinicopathological information and prognostic factors in these cases are scarce. The aim of this study was to construct a prediction index to compare with traditional prognostic models.

Methods

Retrospectively enrolled, previously untreated FL/DLBCL (n = 121) patients, as well as those with pure FL 1-3a (n = 471), were assessed. De novo DLBCL (n = 529) were used as controls. Kaplan-Meier curves were plotted to compare the outcomes among the three groups. Multivariate analysis identified risk factors associated with overall survival (OS) in FL/DLBCL patients. A clinicopathological prognosis index (CPPI) was developed to predict OS based on the Cox proportional hazards model.

Results

The outcomes of FL/DLBCL patients were intermediate between pure FL 1-3a and de novo DLBCL patients, with a 5-year PFS of 70%, 59%, and 48% (P < 0.05) and 5-year OS of 80%, 70% and 60% (P < 0.05), respectively. Cox regression analysis showed that the prognostic factors of OS for FL/DLBCL patients included FL grade, cell of origin, and Ann Arbor stage. A nomogram and clinicopathological prognostic index (CPPI) were developed to predict the OS for FL/DLBCL patients based on these factors. The area under the curve (AUC) of the CPPI for 3- and 5-year OS prediction was 0.782 and 0.860, respectively. This was superior to that of the International Prognostic Index (IPI), Follicular Lymphoma International Prognostic Index (FLIPI), and FLIPI2 in the 0.540-0.819 (P < 0.01) range.

Conclusions

A valid OS estimation in FL/DLBCL patients, using the recommended CPPI, may be useful in routine clinical practice.

Cerebellum/liver index in pretherapeutic 18F-FDG PET/CT as a predictive marker of progression-free survival in follicular lymphoma treated by immunochemotherapy and rituximab maintenance

ABSTRACT

The purpose of this study was to investigate the value of the "cerebellum/ liver index for prognosis" (CLIP) as a new prognostic marker in pretherapeutic 18F-Fluorodeoxyglucose positron emission tomography (18F-FDG PET) in patients with follicular lymphoma treated by immunochemotherapy and rituximab maintenance, focusing on progression-free survival (PFS).Clinicobiological and imaging data from patients with follicular lymphoma between March 2010 and September 2015 were retrospectively collected and 5-year PFS was determined. The conventional PET parameters (maximum standardized uptake value and total metabolic tumor volume) and the CLIP, corresponding to the ratio of the cerebellum maximum standardized uptake value over the liver SUVmean, were extracted from the pretherapeutic 18F-FDG PET.Forty-six patients were included. Eighteen patients (39%) progressed within the 5 years after treatment initiation. Five-year PFS was 78.6% when CLIP was >4.0 and 42.0% when CLIP was <4.0 (P = .04). CLIP was a significant predictor of PFS on univariate analysis (hazard ratio 3.1, P = .049) and was near-significant on multivariate analysis (hazard ratio 2.8, P = .07) with ECOG PS as a cofactor.The CLIP derived from pretherapeutic 18F-FDG PET seems to be an interesting predictive marker of PFS in follicular lymphoma treated by immunochemotherapy and rituximab maintenance. These results should be evaluated prospectively in a larger cohort.

Follicular lymphoma: updates for pathologists

Follicular lymphoma (FL) is the most common indolent B-cell lymphoma and originates from germinal center B-cells (centrocytes and centroblasts) of the lymphoid follicle. Tumorigenesis is believed to initiate early in precursor B-cells in the bone marrow (BM) that acquire the t(14;18)(q32;q21). These cells later migrate to lymph nodes to continue their maturation through the germinal center reaction, at which time they acquire additional genetic and epigeneticabnormalities that promote lymphomagenesis. FLs are heterogeneous in terms of their clinicopathologic features. Most FLs are indolent and clinically characterized by peripheral lymphadenopathy with involvement of the spleen, BM, and peripheral blood in a substantial subset of patients, sometimes accompanied by constitutional symptoms and laboratory abnormalities. Diagnosis is established by the histopathologic identification of a B-cell proliferation usually distributed in an at least partially follicular pattern, typically, but not always, in a lymph node biopsy. The B-cell proliferation is biologically of germinal center cell origin, thus shows an expression of germinal center-associated antigens as detected by immunophenotyping. Although many cases of FLs are typical and histopathologic features are straightforward, the biologic and histopathologic variability of FL is wide, and an accurate diagnosis of FL over this disease spectrum requires knowledge of morphologic variants that can mimic other lymphomas, and rarely non-hematologic malignancies, clinically unique variants, and pitfalls in the interpretation of ancillary studies. The overall survival for most patients is prolonged, but relapses are frequent. The treatment landscape in FL now includes the application of immunotherapy and targeted therapy in addition to chemotherapy.

Follicular lymphoma: is there an optimal way to define risk?

Follicular lymphoma (FL) has a long natural history and typically indolent behavior. In the present era, there are a plethora of prognostic factors combining clinical, biological, and genetic data to determine patient prognosis and help develop treatment strategies over the course of a patient's lifetime. The rapid pace of tumor-specific and clinical advances in FL has created a challenge in the prioritization and implementation of these factors into clinical practice. Developing a comprehensive understanding of existing prognostic markers in FL will help select optimal ways of utilization in the clinical setting and investigate opportunities to define and intervene upon risk at FL diagnosis and disease recurrence.

Follicular Lymphoma in Young Adults: Study from a Regional Cancer Center in South India

Objective Follicular lymphoma (FL) is a disease of the elderly. It is postulated that younger patients have distinct tumor biology and treatment outcomes. Various lymphoma groups across the world have studied this to understand if young adults (YAs) need a different treatment approach. Our study fills the void in data from an Asian country on YA population with FL. Patients and Methods We retrospectively analyzed young patients (age ≤40 years) diagnosed with FL at our center from 2012 to 2018. Their disease characteristics, treatment details, and outcomes were studied to examine any association between various parameters and survival. Results There were 28 young FL patients included in our study that constituted 14.6% of FL cases (males: 53.5% and females: 46.5%). The median age at diagnosis was 36.5 years. Most of the patients presented in an advanced stage, 57% had extranodal involvement, and 39.3% had bone marrow involvement at the time of presentation. The most common chemotherapy regimen used was cyclophosphamide, vincristine, and prednisone. Half of them received chemoimmunotherapy and only 18% continued rituximab as maintenance therapy. The overall response rate was 92.9% ( n = 26), and the remaining two patients had progressive disease while on treatment. The median progression free survival (PFS) was 6.1 years and median overall survival (OS) was not reached. On univariate analysis, extranodal disease was associated with a lower PFS ( p = 0.06) and low hemoglobin showed a significant association with OS ( p = 0.005). On multivariate analysis, none of the factors showed a significant association with survival. Conclusion Most YAs present with advanced disease with a good response to treatment and favorable outcomes.

PET Imaging for Hematologic Malignancies

Hematologic malignancies are a broad category of cancers arising from the lymphoid and myeloid cell lines. The 2016 World Health Organization classification system incorporated molecular markers as part of the diagnostic criteria and includes more than 100 subtypes. This article focuses on the subtypes for which imaging with positron emission tomography/computed tomography (PET/CT) has become an integral component of the patient's evaluation, that is, lymphoma and multiple myeloma. Leukemia and histiocytic and dendritic cell neoplasms are also discussed as these indications for PET/CT are less common, but increasingly seen in clinic.

Relative frequency and clinicopathologic characteristics of MYC-rearranged follicular lymphoma

MYC rearrangement is a relatively rare genetic abnormality in follicular lymphoma (FL). In this study, we evaluated the relative frequency of MYC rearrangement in 522 cases of FL and studied their clinicopathologic, cytogenetic, and molecular characteristics. Fluorescence in situ hybridization studies for MYC (break-apart probe), MYC/IGH, IGH/BCL2, and BCL6 rearrangements were performed on tissue microarrays. Immunohistochemical stains for CD10, BCL2, BCL6, and MYC were performed and scored on MYC-rearranged cases. On 4 FL cases, a custom targeted panel of 356 genes was used for mutation analysis. Ten cases (1.9%) were positive for MYC rearrangement. Histologically, 6 of 10 cases were grade 1-2, and 4 cases were grade 3A. By immunohistochemistry, 9 of 9 tested cases were CD10+, all cases were BCL6+, and 9/10 cases were BCL2+. MYC protein staining was low in all cases tested. IGH/BCL2 rearrangement was detected in 5 of 9 cases, whereas BCL6 rearrangement was detected in 3 of 7 tested cases and 4 of 10 cases showed MYC/IGH rearrangement. The most commonly detected mutations in the MYC-positive cases included HLA-B, TNFRSF14, and KMT2D. MYC and/or B2M abnormalities were detected in 2 cases. In conclusion, MYC rearrangement is uncommon in FL and these cases do not appear to have specific histologic characteristics. Molecular analysis showed abnormalities in genes associated with transformation, namely MYC and B2M. Larger studies are needed to evaluate if MYC-rearrangement in FL has prognostic significance.

Immune infiltrate diversity confers a good prognosis in follicular lymphoma

Background

Follicular lymphoma (FL) prognosis is influenced by the composition of the tumour microenvironment. We tested an automated approach to quantitatively assess the phenotypic and spatial immune infiltrate diversity as a prognostic biomarker for FL patients.

Methods

Diagnostic biopsies were collected from 127 FL patients initially treated with rituximab-based therapy (52%), radiotherapy (28%), or active surveillance (20%). Tissue microarrays were constructed and stained using multiplex immunofluorescence (CD4, CD8, FOXP3, CD21, PD-1, CD68, and DAPI). Subsequently, sections underwent automated cell scoring and analysis of spatial interactions, defined as cells co-occurring within 30 μm. Shannon’s entropy, a metric describing species biodiversity in ecological habitats, was applied to quantify immune infiltrate diversity of cell types and spatial interactions. Immune infiltrate diversity indices were tested in multivariable Cox regression and Kaplan–Meier analysis for overall (OS) and progression-free survival (PFS).

Results

Increased diversity of cell types (HR = 0.19 95% CI 0.06–0.65, p = 0.008) and cell spatial interactions (HR = 0.39, 95% CI 0.20–0.75, p = 0.005) was associated with favourable OS, independent of the Follicular Lymphoma International Prognostic Index. In the rituximab-treated subset, the favourable trend between diversity and PFS did not reach statistical significance.

Conclusion

Multiplex immunofluorescence and Shannon’s entropy can objectively quantify immune infiltrate diversity and generate prognostic information in FL. This automated approach warrants validation in additional FL cohorts, and its applicability as a pre-treatment biomarker to identify high-risk patients should be further explored. The multiplex image dataset generated by this study is shared publicly to encourage further research on the FL microenvironment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00262-021-02945-0.

The diagnostic and therapeutic challenges of Grade 3B follicular lymphoma

Grade 3B follicular lymphoma (G3B FL) is rare, accounting for only 5-10% of FLs. Not only has it been routinely excluded from clinical trials, but data published on diagnosis, outcomes, choice of therapies and role of imaging are conflicting. With the advent of increasingly diverse treatment options for low-grade (G1-3A) FL, and the molecular subcategorisation of high-grade B-cell lymphomas, characterisation and treatment of G3B FL is ever more important as extrapolation of data becomes more difficult. New data have emerged exploring unique genetic characteristics, specific features on positron emission tomography imaging, choice of therapy, and outcomes of G3B FL in the current era. The present review will summarise and appraise these new data, and offer recommendations based on current evidence.

Novel Therapy Approaches to Follicular Lymphoma

Follicular lymphoma (FL) is the most common form of indolent non-Hodgkin lymphoma. It is a disease characterised by a long median overall survival and high response rates to currently available chemotherapy and anti-CD20 monoclonal antibody therapy combinations. However, for a sub-group of patients the disease behaves aggressively, fails to respond adequately to initial therapy or relapses early. For others, the disease becomes resistant following multiple lines of therapy, and despite recent advances the main cause of death for patients with FL remains their lymphoma. A wide landscape of novel therapies is emerging and the role of individual agents in the FL treatment paradigm is still being established. Some agents, including the cereblon modulator lenalidomide, the phosphatidylinositol 3-kinase inhibitors idelalisib, copanlisib and duvelisib, and the EZH2 inhibitor tazemetostat have received regulatory approval in the USA or European Union and have entered clinical practice for relapsed FL. Other developments, such as the emergence of immunotherapies including CAR-T cell therapy and bispecific antibodies, are expected to fundamentally change the approach to FL treatment in the future.

Prognostic significance of histologic grade and Ki-67 proliferation index in follicular lymphoma

The prognostic value of histologic grading and the Ki-67 proliferation index in follicular lymphoma (FL) is controversial. This study investigated the clinical usefulness of these two factors in Asian FL patients. Four hundred and thirty-three patients diagnosed with FL were retrospectively reviewed with a median follow-up time of 47.0 months (range, 24.0-168.0). The 10-year overall survival (OS) rate and progression-free survival (PFS) rate were 91.0% and 47.1%, respectively. Grade 3B and grade 3B with diffuse large B cell lymphoma (DLBCL) showed a better PFS than grade 1-3A (P < 0.001), and similar findings were noted in patients who received rituximab-containing regimens (P = 0.002). In contrast, no significant differences in terms of OS or PFS were observed between grades 1-2 and 3A. In addition, patients with Ki-67 ≥ 30% had a significantly better PFS than patients with Ki-67 < 30% (P = 0.014), although the difference was eliminated in the multivariate analysis. Both grade and Ki-67 index had no impact on prognosis in patients who did not receive rituximab treatment. In conclusion, grade 3A is closely related to grade 1-2, as reflected by a similar indolent clinical course and a lower PFS rate than grade 3B/3B + DLBCL. In addition, a higher Ki-67 index seems to have a positive effect on PFS in FL patients.

Clinical and Biological Prognostic Factors in Follicular Lymphoma

Follicular lymphoma comprises approximately 20-30% of all cases of B-cell lymphomas. Median survival has improved significantly in the modern era. Prognostic factors include histologic grade, cytogenetics, molecular mutations, the tumor microenvironment, and tumor burden. Clinical prognostic indices are available and increasingly incorporate genetic information. Prognostic factors also arise during the course of treatment. Early progression within 24 months of initial chemoimmunotherapy is an adverse prognostic marker of inferior survival. Other high-risk populations include those with double refractory disease or those with high risk of transformation to diffuse large B-cell lymphoma.

Follicular lymphoma: 2020 update on diagnosis and management

DISEASE OVERVIEW

Follicular lymphoma (FL) is generally an indolent B cell lymphoproliferative disorder of transformed follicular center B cells. Follicular lymphoma is characterized by diffuse lymphadenopathy, bone marrow involvement, and splenomegaly. Extranodal involvement is less common. Cytopenias are relatively common but constitutional symptoms of fever, night sweats, and weight loss are uncommon in the absence of transformation to diffuse large B cell lymphoma.

DIAGNOSIS

The diagnosis is based on histology from a biopsy of a lymph node or other affected tissue. Incisional biopsy is preferred over needle biopsies in order to give adequate tissue to assign grade and assess for transformation. Immunohistochemical staining is positive in virtually all cases for cell surface CD19, CD20, CD10 and monoclonal immunoglobulin, as well as cytoplasmic expression of bcl-2 protein. The overwhelming majority of cases have the characteristic t(14;18) translocation involving the IgH/bcl-2 genes.

RISK STRATIFICATION

The Follicular Lymphoma International Prognostic Index (FLIPI) uses five independent predictors of inferior survival: age > 60 years, hemoglobin <12 g/dL, serum LDH > normal, Ann Arbor stage III/IV, number of involved nodal areas >4. The presence of 0-1, 2, and ≥ 3 adverse factors defines low, intermediate, and high-risk disease. There are other clinical prognostic models but the FLIPI remains the most common. Other factors such as time to relapse of less than 2 years from chemoimmunotherapy and specific gene mutations may also be useful for prognosis. Regardless of the prognostic model used, modern therapies have demonstrably improved prognosis.

RISK-ADAPTED THERAPY

Observation continues to be appropriate for asymptomatic patients with low bulk disease and no cytopenias. There is no overall survival advantage for early treatment with either chemotherapy or single agent rituximab. For patients needing therapy, most patients are treated with chemoimmunotherapy, which has improved response rates, duration of response and overall survival (OS). Randomized studies have shown additional benefit for maintenance rituximab. Lenalidomide was non-inferior to chemoimmunotherapy in a randomized front-line study and, when combined with rituximab, was superior to rituximab alone in relapsed FL. Kinase inhibitors, other immunotherapies, and stem cell transplantation (SCT) are also considered for recurrent disease.

Long-term outcome comparing histological grades of follicular lymphoma patients treated with immunochemotherapy as first-line therapy: A retrospective analysis from two institutions

OBJECTIVES

To clarify the impact of histological grades in follicular lymphoma.

METHODS

We retrospectively analysed 250 patients diagnosed with FL treated with chemoimmunotherapy: 188 patients were grades 1-2 and 62 grade 3A.

RESULTS

In our series, grade 3A FL patients were older, higher proportion of localised disease and lower bone marrow infiltration at diagnosis comparing grades 1-2 FL patients. Estimated six-year progression-free survival and time to progression showed no differences between both groups [grade 3A: 56% (95%CI: 39%-73%) and 51% (95%CI: 41%-61%) vs grades 1-2:55% (95%CI: 46%-63%) and 57% (95%CI: 49%-65%), P = .782 and P = .521, respectively]. Estimated six-year overall survival was lower, 76% (95%CI: 64%-88%) for the grade 3A group than grades 1-2 83% (95%CI: 77%-89%); P = .044. In addition to that, cumulative incidence curves of death not related to lymphoma at 10 years between groups were as follows: [0.26 (95%CI: 0.25-0.27) and 0.05 (95%CI: 0.04-0.06) for G3AFL and G1-2FL, respectively], P = .010. Grade 3A FL showed in PFS curve no relapses after 6 years. These results were absolutely reproduced in 199 patients receiving R-CHOP regimen as induction.

CONCLUSIONS

Our results indicate similar long-term outcomes in terms of progression-free survival and time to progression in grades 1-2 and 3A. No relapses were observed in G3AFL group after 6 years.

Changing trends in lymphoid neoplasm distribution in South Korea: analysis of 8615 cases from a single institute, 1997-2016: An observational study

The purpose of this study was to evaluate changes in the proportion of lymphoid neoplasm subtypes in South Korea. A total of 8615 cases of lymphoid neoplasms diagnosed in 1997-2016 at Samsung Medical Center in South Korea were classified according to the 2008 World Health Organization system. The total number and proportion of lymphoid neoplasms were compared between these two decades, with data from nationwide studies, and with other countries. To evaluate changes in the proportion of subtypes, crude rate of each subtype per 100 lymphoma patients during each decade and age adjusted rate were calculated. There were 3024 patients with lymphoid neoplasm in 1997-2006, and 5591 in 2007-2016, which represents an average increase of 1.85 times over the 20-year study period. Crude rate and age adjusted rate were increased in Hodgkin's lymphoma and mature B cell lymphoma while precursor lymphoid neoplasms and mature T cell lymphoma were decreased. Among B cell neoplasms, age adjusted rate of plasma cell neoplasm, follicular lymphoma, mantle cell lymphoma increased while there was no significant change in extranodal marginal zone lymphoma and Burkitt lymphoma. The increase in follicular lymphoma was due to the increases in nodal follicular lymphoma of low grade and duodenal-type follicular lymphoma. These results are consistent with the dynamics of causative factors, including socioeconomic factors, in Korea.

[Follicular lymphoma: first - line selection criteria of treatment]

Follicular lymphoma (FL) is a tumor that develops from the B cells of the germinal center; characterized by recurrent and remitting course of the disease, the transformation of a tumor into diffuse large B-cell lymphoma (DLBCL) is possible. In generalized lesions and progression of FL, the most commonly used courses are R-CHOP and R-B. The choice of therapy for different cytological types, clinical and laboratory parameters remains disputable.

AIM

To analyze the clinical, laboratory, morphological parameters of patients with FL, who got R-B and R-CHOP therapy; determine the criteria for selecting induction therapy.

MATERIALS AND METHODS

The study included 203 patients with FL from 2000 to 2018. R-CHOP treatment was initiated in 126 patients, 14 of whom later received high - dose therapy (HDT) (R-DHAP: rituximab, dexamethasone, cisplatin, cytarabine) without autologous stem cell transplantation (autoSCT), 21 - HDT with autoSCT; treatment of 89 patients was limited to courses of R-CHOP and maintenance therapy with rituximab, two patients (in whom the disease progressed, despite R-CHOP therapy) were assigned the mNHL-BFM-90 program. The efficacy of treatment on various treatment regimens was evaluated primarily by overall survival.

RESULTS AND DISCUSSION

R-B. 77 patients received R-B therapy. Complete remission of the disease was achieved in 47/77 (61%) patients (3 of them later developed a relapse of the disease), partial remission was achieved in 15/77 (19%) patients, in 13/77 (17%) cases progression was recorded tumors. 70 patients had 1-2 cytological type of tumor, 6 patients - 3A cytological type. In cases of progression, 3 of 13 patients (46%) were diagnosed with 3A cytological type FL. Median observation (at the time of analysis) - 34 months. R-CHOP. 89 patients with FL received high - dose therapy with R-CHOP (6-8 courses) and maintenance therapy with rituximab. In 39 (44%) patients, the disease remained in remission, and in 50 (56%), a relapse of the disease developed. 50 patients had 1-2 cytological types, 39 - 3 cytological types. In cases of recurrence of FL, a 3A cytologic type (36%) was diagnosed in 18/50 patients. Median observation - 93 months. R-CHOP + HDT and autoSCT. 21 patients after the R-CHOP courses continued (due to insufficient antitumor response) high - dose chemotherapy (HDT) and auto-SCT were performed. In 18/21 (86%) cases, complete remission of the disease was achieved and maintained, in 3 (14%) cases relapse developed. 16 patients had 1-2 cytological types, 5 - 3 cytological types. Median observation - 81 months. R-CHOP + HDT without autoSCT. 14 patients started therapy under the R-CHOP program as induction therapy, but then (due to insufficient antitumor response), the treatment was continued according to the HDT without autoSCT. 11 (79%) patients are currently in remission of the disease, in 3 (21%) - there was a relapse. 10 patients had 2 cytological types of PL, 4 - 3 cytological types. 11 (79%) patients are currently in remission of the disease, in 3 (21%) - there was a relapse. Median observation - 80 months. 7-year OS of patients with FL on RB therapy was 89% (95% CI 75-99), on R-CHOP therapy - 85% (95% CI 73-90), on R-CHOP + HDT and autoSCT - 87% (95% CI 57-100), on R-CHOP + HDT without autoSCT - 82%. 7-year PFS of FL patients on RB therapy was 70% (95% CI 75-99), on R-CHOP therapy - 44% (95% CI 73-90), on R-CHOP + HDT and autoSCT - 74% (95% CI 57-100), on R-CHOP + HDT without autoSCT - 80%.

CONCLUSION

The R-B is most effective in FL 1 and 2 cytological types. The cytological type does not correspond to the type of tumor growth: at 3A and 3A + 3B cytological types, nodular / nodular - diffuse and diffuse types of growth are found. When choosing an induction course, one should look at the cytological type of FL. A high proliferative activity index (according to Ki67) is a predictor of resistance to R-B therapy. The absence of an interfollicular T-cell reaction in tumor tissue FL is associated with tumor chemoresistance. The presence of the bulky factor is associated (in most patients) with the FLIPI index with values from 3 to 5, and is a predictor of a poor response to therapy. Patients with bulky, high (more than 35%) Ki67 index and FLIPI from 3 to 5 in the debut of the disease as the first line therapy, it is preferable to choose the R-CHOP mode, and in the absence of (after 4-6 courses) to complete or partial remission to continue conducting the HDT.

Primary non-ampullary duodenal follicular lymphoma presenting with obstructive jaundice

Primary gastrointestinal follicular lymphoma is a rare disease. Follicular lymphoma does not cause any typical symptoms, although it usually shows the presence of multiple white granules on endoscopy. Few patients with follicular lymphoma present with the initial symptom of jaundice, which is usually associated with follicular lymphomas located in the papilla of Vater. Herein, we present the first case of a duodenal follicular lymphoma that presented with obstructive jaundice despite not being located in the ampulla, and it did not demonstrate the typical endoscopic findings of multiple white granules. A 72-year-old Japanese man with jaundice was referred to our hospital. Imaging revealed a hypovascular lesion extending into the second part of the duodenum and the pancreatic head, and the common bile duct was dilated upstream of the lesion. Biopsy of the lesion was negative for malignancy. Finally, we suspected the lesion as a pancreatic adenosquamous carcinoma, and not a typical pancreatic ductal carcinoma, because the lesion showed no pancreatic duct dilation and had a partially hyperechoic part within. Therefore, we performed pancreaticoduodenectomy. The final diagnosis was a duodenal follicular lymphoma. The findings of this case may assist in distinguishing between atypical follicular lymphoma and jaundice from pancreatic cancer.

Predictive Value of Interim and End-of-Therapy 18F-FDG PET/CT in Patients with Follicular Lymphoma

PURPOSE

18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is the standard imaging modality for response evaluation in FDG-avid lymphoma, but the prognostic value is not established in follicular lymphoma (FL). This study investigated the prognostic value of Deauville 5-point scale (D5PS) from paired interim PET/CT (PETInterim) and end-of-induction therapy PET/CT (PETEOI) in patients with FL.

METHODS

FL staging and response assessment PET/CT images from 2013 to 2015 were retrospectively reviewed. PETInterim was performed 3 or 4 cycles after chemotherapy and PETEOI after 6 or 8 cycles. D5PS scores of 1, 2, and 3 were considered as negative (-), and scores 4 and 5 were considered as positive (+). Statistical analysis was done using Cox regression analysis, Kaplan-Meier survival analysis, and the log-rank test.

RESULTS

Thirty-three patients with set of baseline, interim, and end-of-induction therapy PET/CT studies were included. Ten patients (30.3%) had progression. The median progression-free survival (PFS) was 38.8 months (range 3.5-72.7 months). On PETInterim, 23 patients were negative and 10 were positive. On PETEOI scans, 29 patients were negative, and 4 were positive. On multivariate analysis, PETEOI(-) was associated with longer PFS. PETInterim(+) and PETEOI(+) patients had a significantly shorter PFS than PETInterim(-) patients (39.9 months, 95% confidence interval [CI] 23.0-56.9, versus 55.5 months, 95% CI 49.7-61.2, p = 0.005) and PETEOI(-) patients (14.2 months, 95% CI 8.5-19.8, versus 60.5 months, 95% CI 52.1-69.0, p < 0.001).

CONCLUSION

For patients with FL, PETInterim and PETEOI response is predictive of PFS, and PETEOI(+) is an independent prognostic factor for progression of FL.

The Utility of Phosphohistone H3 (PHH3) in Follicular Lymphoma Grading: A Comparative Study With Ki-67 and H&E Mitotic Count

OBJECTIVES

To determine the utility of phosphohistone H3 (PHH3) mitotic count (MC) in grading follicular lymphoma (FL).

METHODS

FL cases were identified (2005-2017). Three hematopathologists recorded their average Ki-67 proliferation index, MC/high-power field (hpf) using PHH3 and H&E stains, and number of centroblasts/hpf. Results were assessed for correlations and interobserver variability.

RESULTS

Forty-three cases of FL were studied. PHH3 MC resulted in the strongest correlation to grade (r = 0.701, P < .0001) compared with Ki-67 proliferation index (PI) (r = 0.681, P < .0001) and H&E MC (r = 0.536, P = .0002) and the strongest linear relationship to centroblast count (R2 = 0.453). Agreement among pathologists was strongest for PHH3 (intraclass correlation coefficient [ICC] = 0.86) followed by Ki-67 PI (ICC = 0.85) and H&E MC (ICC = 0.78).

CONCLUSIONS

PHH3 correlates best to histologic grade and has less interobserver variability compared with Ki-67 PI and H&E MC. These results support using PHH3 as an adjunct in FL grading.

Limited stage grade 3 follicular lymphoma patients can experience favorable outcomes with combined modality therapy

Controversy exists regarding the optimal management of limited stage grade 3 follicular lymphoma (FL3). We assessed the treatment outcomes of 190 consecutive patients with stage I-II FL. Fifty two patients had FL3 disease, in whom the median age was 55 years. At a median follow-up of 65 months, 5-year progression-free survival (PFS) and overall survival (OS) rates were 76.6% and 87.6%, respectively. Patients receiving systemic therapy followed by radiation therapy (RT) had a significantly better PFS (p=.003) than those treated with RT alone, but similar OS (p = .476). Patients treated with RT had 100% local control. Compared to 132 patients with grade 1-2 FL, those with FL3 had similar PFS (p = .493) and OS (p  =  .330). Patients with FL3 can experience favorable outcomes when treated with a combination of systemic therapy and RT, comparable to low grade FL.

[Prognostic study of 229 follicular lymphoma patients treated with rituximab combined with chemotherapy]

Objective: To explore the clinical characteristics of follicular lymphoma (FL) in the era of rituximab combined with chemotherapy and the prognostic significance of the follicular lymphoma international prognostic index (FLIPI), follicular lymphoma international prognostic index 2 (FLIPI2), international prognostic index (IPI), revised international prognostic index (R-IPI), National Comprehensive Cancer Network international prognostic index (NCCN-IPI) among Chinese patients. Methods: 229 FL patients who were treated initially with rituximab combined with CHOP-like (cyclophosphamide, doxorubicin, vincristine and prednisone) chemotherapy from November 2008 to April 2018 were analyzed retrospectively and all were scored by the above clinical index. Univariate and multivariate survival analysis were performed on 201 patients who completed the treatment and were followed regularly. Results: In the univariate survival analysis, age>60 years, hemoglobin<120 g/L, elevated serumβ(2)- macroglobulin, involvement of bone marrow and elevated CRP were the risk prognostic factors for overall survival (OS) and progression free survival (PFS). Moreover, the analysis of the OS and PFS between rituximab (R) maintenance (RM) group and non-maintenance (non-RM) group showed that the OS and PFS of RM group were better than those of non-RM. In the multivariate analysis of OS, hemoglobin<120 g/L, involvement of bone marrow, elevated CRP and non-RM were independent prognostic factors. In the multivariate analysis of PFS, hemoglobin<120 g/L, CRP and non-RM were independent prognostic factors. When FLIPI2 was included in the multivariate analysis, CRP and FLIPI2 were independent prognostic factors in both OS and PFS, and non-RM was independent prognostic factors in PFS. Conclusion: FLIPI2 is the better risk stratification in FL patients in the era of rituximab.

Six versus eight doses of rituximab in patients with aggressive B cell lymphoma receiving six cycles of CHOP: results from the "Positron Emission Tomography-Guided Therapy of Aggressive Non-Hodgkin Lymphomas" (PETAL) trial

Standard first-line treatment of aggressive B cell lymphoma comprises six or eight cycles of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) plus eight doses of rituximab (R). Whether adding two doses of rituximab to six cycles of R-CHOP is of therapeutic benefit has not been systematically investigated. The Positron Emission Tomography-Guided Therapy of Aggressive Non-Hodgkin Lymphomas (PETAL) trial investigated the ability of [¹⁸F]-fluorodesoxyglucose PET scanning to guide treatment in aggressive non-Hodgkin lymphomas. Patients with B cell lymphomas and a negative interim scan received six cycles of R-CHOP with or without two extra doses of rituximab. For reasons related to trial design, only about a third underwent randomization between the two options. Combining randomized and non-randomized patients enabled subgroup analyses for diffuse large B cell lymphoma (DLBCL; n = 544), primary mediastinal B cell lymphoma (PMBCL; n = 37), and follicular lymphoma (FL) grade 3 (n = 35). With a median follow-up of 52 months, increasing the number of rituximab administrations failed to improve outcome. A non-significant trend for improved event-free survival was seen in DLBCL high-risk patients, as defined by the International Prognostic Index, while inferior survival was observed in female patients below the age of 60 years. Long-term outcome in PMBCL was excellent. Differences between FL grade 3a and FL grade 3b were not apparent. The results were confirmed in a Cox proportional hazard regression model and a propensity score matching analysis. In conclusion, adding two doses of rituximab to six cycles of R-CHOP did not improve outcome in patients with aggressive B cell lymphomas and a fast metabolic treatment response.

Multicenter Analysis of Advanced Stage Grade 3A Follicular Lymphoma Outcomes by Frontline Treatment Regimen

BACKGROUND

Follicular lymphoma (FL) is a common form of non-Hodgkin lymphoma with a wide spectrum of presentation. While grade 1/2 FL is considered low grade and grade 3B FL is approached as an aggressive lymphoma, the management of grade 3A FL remains controversial.

PATIENTS AND METHODS

We performed a retrospective, multicenter analysis of patients aged ≥ 18 years with advanced stage 3/4 grade 3A FL diagnosed between January 2006 and July 2016. Patients were stratified by frontline chemotherapy regimen: anthracycline based (ATC), bendamustine (BD), and cyclophosphamide, vincristine, and prednisone (CVP). A total of 103 patients were identified from 6 contributing centers: 65 patients received ATC chemotherapy, 30 BD, and 8 CVP. The primary outcome was time to progression (TTP). Secondary outcomes included progression-free survival, overall survival, complete response rates, large cell transformation, and impact of standardized maximum uptake value on positron emission tomography/computed tomography with outcomes. Patient characteristics were similar among the 3 treatment groups.

RESULTS

For TTP at 24 months from initiation of treatment, 72% of ATC, 79% of BD, and 50% of CVP patients had not experienced disease progression (P = .01). Multivariate analysis demonstrated a TTP benefit for ATC compared to CVP (hazard ratio 3.22; 95% confidence interval, 1.26-8.25; P = .01) but no difference when compared to BD. Similar findings were seen with progression-free survival. While overall survival was similar among the 3 arms, there was a higher risk of large cell transformation following BD and CVP. Last, standardized maximum uptake value on positron emission tomography/computed tomography did not affect TTP when comparing BD- and ATC-treated patients.

CONCLUSION

Although ATC was superior to CVP, clinical outcomes (TTP, progression-free survival, and overall survival) were similar compared to BD chemotherapy for patients with grade 3A FL.

Follicular Lymphoma Diagnostic Caveats and Updates

CONTEXT.—

Follicular lymphoma is a common small B-cell lymphoma, likely to be encountered by any practicing pathologist, regardless of specialty. Although the features of typical follicular lymphoma are well known and in most instances easily identifiable, there are lesser-appreciated morphologic appearances that can raise alternative diagnostic possibilities. The limited tissue available in core needle biopsies can make it additionally challenging to thoroughly evaluate those features in the context of architecture. Furthermore, ancillary testing including immunohistochemistry and molecular/genetic analysis do not always show classic findings and may pose additional challenges to interpretation.

OBJECTIVES.—

To review the morphologic features of follicular lymphoma with a discussion of morphologic variants and mimics; to discuss pitfalls of ancillary testing and provide the practicing pathologist with an appropriate context for interpretation of immunohistochemical and molecular/genetic studies when follicular lymphoma is part of the differential diagnosis; and to propose diagnostic strategies when there is limited tissue for evaluation.

DATA SOURCES.—

We used examples of follicular lymphoma from our institution as well as a review of the literature, with a focus on the diagnostic aspects that are broadly relevant to a general pathology practice.

CONCLUSIONS.—

Follicular lymphoma can occasionally present with atypical morphologic, immunohistochemical, or molecular/genetic features. In particular, those findings can be difficult to interpret in the setting of a limited tissue sample. Awareness of those possibilities will help guide the pathologist to a more accurate and precise diagnosis.

[Clinical characteristics and survival analysis of de novo grade 3 or transformed follicular lymphoma patients]

Objective: To evaluate the clinical characteristics and survival outcomes of patients with de novo grade 3 or transformed follicular lymphoma (FL). Methods: Fifty-two patients treated at Peking University Cancer Hospital between January 2009 and September 2017 were assessed, including 28 patients with FL 3A grade, 13 patients with FL 3B grade, 11 patients with transformed FL. Baseline characteristics, survival and prognostic factors were analyzed. Results: ① Twenty-six male and 26 female patients were enrolled, including 28 patients with FL 3A grade, 13 patients with FL 3B grade, 11 patients with transformed FL. ②The 3-year progression-free survival (PFS) and overall survival (OS) for the entire cohort were 56.0% and 80.6%, respectively. Patients with international prognostic index (IPI) score 0-1 demonstrated significantly better 3-year PFS (80.3% vs 20.1%; t=18.902, P<0.001) and OS (95.7% vs 57.0%; t=10.406, P<0.001) than patients with IPI score 2-3. Three-year PFS (94.1% vs 37.2% vs 25.2%; P=0.002) and OS (100.0% vs 76.0% vs 59.8%; P=0.020) were also significantly different among patients with FLIPI 1 score 0-1, 2, ≥3. FLIPI 2 score was also identified as a prognostic factor for 3-year PFS (68.4%, 0, 0; P=0.001) and OS(87.5%, 76.2%, 0; P=0.003). ③Multivariate analysis indicated a significant association of PFS (HR=3.536, P=0.015) and OS (HR=15.713, P=0.015) with IPI. FLIPI 2 was associated with OS (score 0-1, HR=0.078, P=0.007; score 2, HR=0.080, P=0.022). Conclusion: De novo grade 3 or transformed FL might be a group of curable disease with current treatment strategies. IPI is still a prognostic tool in this scenario.

Efficacy of Idelalisib as Bridge to Allogeneic Stem Cell Transplant in Relapsed Follicular Lymphoma: A Case Report

Purpose

A large number of new therapeutic agents have been studied for patients with relapsed/refractory follicular lymphoma (FL). Among new therapies, idelalisib, a novel PI3K inhibitor, shows promising results in the management of this disease.

Case report

We describe the case of a 39-year-old patient with a diagnosis of grade 3a FL and a Follicular Lymphoma International Prognostic Index score of 2, who underwent several lines of therapy (including autologous stem cell transplant) with transient responses or no response at all. The patient was subsequently treated with 5 courses of idelalisib monotherapy, achieving a partial response. No relevant toxicities occurred. The patient underwent allogeneic stem cell transplant (allo-SCT) from an unrelated donor and obtained a complete response, which was confirmed after 3, 6, 9, and 12 months, and is still ongoing.

Conclusions

As previously reported, the achievement of a good response is predictive for a better outcome after allo-SCT: idelalisib represents an effective treatment option for patients with relapsed/refractory FL, which can also be adopted as a bridge to allo-SCT.

Rituximab maintenance therapy of follicular lymphoma in clinical practice

Standard of care for patients with symptomatic, advanced‐stage follicular lymphoma (FL) is rituximab‐containing chemoimmunotherapy followed by rituximab maintenance. This prospective, multicenter, noninterventional study analyzed how efficacy and safety data from randomized controlled trials translate into clinical practice in Germany. Both treatment‐naïve and relapsed/refractory patients with FL, who responded to rituximab‐containing induction and were scheduled for rituximab maintenance, were observed for 24 months. Effectiveness was measured by response and Kaplan‐Meier survival analysis. In addition, treatment patterns of induction and maintenance, as well as adverse events, were documented. The evaluable study population consisted of 310 first‐line patients and 173 relapsed/refractory patients, including 116 patients with initial Ann‐Arbor stage I/II and 20 patients with FL grade 3B. Regarding first‐line induction, a shift from R‐CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone) to R‐bendamustine was observed over time, as well as a decline in radiotherapy. 2‐year progression‐free survival rates were 88.3% (95% confidence interval [CI] 84.0‐92.6) for first‐line patients and 76.0% (95% CI: 68.8‐83.3) for relapsed/refractory patients. Conversion from partial to complete remission (PR, CR) occurred in 53.4% of analyzed first‐line patients with PR, resulting in 69.4% CRs at study end (relapsed/refractory: conversion in 42.9%, final CRs 57.9%). Safety results were consistent with the known safety profile of rituximab in this setting. Both treatment‐naïve and relapsed/refractory patients with FL show favorable 2‐year PFS rates and improvements in the remission status with postinduction rituximab monotherapy as maintenance and consolidation therapy.

Characteristics of follicular and mantle cell lymphoma in Brazil: prognostic impact of clinical parameters and treatment conditions in two hospitals

Objective

Follicular and mantle cell lymphoma are low-grade B-cell malignancies that lack good responses to chemoimmunotherapy. This study aimed to assess retrospectively clinicopathological features and to determine independent prognostic factors for follicular and mantle cell lymphoma patients treated at two Brazilian medical centers: the Hematology and Hemotherapy Center of the Universidade Estadual de Campinas (Unicamp), a public university hospital, and AC. Camargo Cancer Center, a specialized cancer center.

Methods

Two hundred and twenty-seven follicular and 112 mantle cell lymphoma cases were diagnosed between 1999 and 2016. Archived paraffin blocks were retrieved and reviewed. Corresponding demographics and clinical data were recovered from medical charts. Outcome analyses considered both overall and event-free survival.

Results

For follicular lymphoma treated with the R-CHOP (rituximab, cyclophosphamide, doxorubicin hydrochloride, vincristine sulfate, prednisone) and R-CVP (rituximab, cyclophosphamide, vincristine sulfate, prednisone) regimens, both B-symptoms (p-value < 0.01 for overall and event-free survival) and high-risk Follicular Lymphoma International Prognostic Index (p-value < 0.01 for overall survival) were independently associated to worse prognosis. Maintenance with rituximab improved the prognosis (p-value < 0.01 for overall survival). For mantle cell lymphoma, B-symptoms (p-value = 0.03 for overall survival and event-free survival) and bone marrow infiltration (p-value = 0.01 for overall survival) independently predicted reduced survival, and rituximab at induction increased both event-free and overall survival (p-value < 0.01 in both analyses). Combinations of these deleterious features could identify extremely poor prognostic subgroups. The administration of rituximab was more frequent in the AC. Camargo Cancer Center, which was the institution associated with better overall survival for both neoplasias.

Conclusion

This study represents the largest cohort of follicular and mantle cell lymphoma in South America thus far. Some easily assessable clinical variables were able to predict prognosis and should be considered in low-income centers. In addition, the underuse of rituximab in the Brazilian public health system should be reconsidered in future health policies.