Relative frequency of non-Hodgkin lymphoma subtypes in selected centres in North Africa, the middle east and India: a review of 971 cases

Epidemiology and etiology of diffuse large B-cell lymphoma

As the most common non-Hodgkin lymphoma subtype, diffuse large B-cell lymphoma (DLBCL) incidence patterns generally parallel that for NHL overall. Globally, DLBCL accounts for a third of all NHLs, ranging between 20% and 50% by country. Based on United States (U.S.) cancer registry data, age-standardized incidence rate for DLBCL was 7.2 per 100,000. DLBCL incidence rises with age and is generally higher in males than females; in the U.S., incidence is highest among non-Hispanic whites (9.2/100,000). Like NHL incidence, DLBCL incidence rose in the first half of the 20th century but has largely plateaued. However, there is some evidence that incidence rates are rising in areas of historically low rates, such as Asia; there are also estimates for rising DLBCL incidence in the near future due to the changing demographics in developed countries whose aging population is growing. Established risk factors for DLBCL include those that result in severe immune deficiency such as HIV/AIDS, inherited immunodeficiency syndromes, and organ transplant recipients. Factors that lead to chronic immune dysregulations are also established risk factors, and include a number of autoimmune conditions (eg, Sjögren syndrome, systemic lupus erythematosus, rheumatoid arthritis), viral infections (eg, HIV, KSHV/HHV8, HCV, EBV), and obesity. Family history of NHL/DLBCL, personal history of cancer, and multiple genetic susceptibility loci are also well-established risk factors for DLBCL. There is strong evidence for multiple environmental exposures in DLBCL etiology, including exposure to trichloroethylene, benzene, and pesticides and herbicides, with recent associations noted with glyphosate. There is also strong evidence for associations with other viruses, such as HBV. Recent estimates suggest that obesity accounts for nearly a quarter of DLBCLs that develop, but despite recent gains in the understanding of DLBCL etiology, the majority of disease remain unexplained. An understanding of the host and environmental contributions to disease etiology, and concerted efforts to expand our understanding to multiple race/ethnic groups, will be essential for constructing clinically relevant risk prediction models and develop effective strategies for disease prevention.

Oral and para-oral lymphomas: a 10-year multi-center retrospective study in Egypt with time series analysis and forecasting to 2030

BACKGROUND

Little is known about the epidemiology of lymphomas occurring in oral and para-oral sites, especially in developing countries such as Egypt. Hence, the aim of this study was to describe the frequency and time trends of oral and para-oral lymphomas in Cairo governorate from 2010 to 2019, with forecasting to 2030, and to examine relations between age, gender, site and type of lymphoma.

METHODS

Histopathological reports of patients diagnosed with oral and para-oral lymphomas from 2010 to 2019 were retrospectively retrieved from archives of six different centers in Cairo governorate. Data regarding age, gender and site was collected and associations between types of lymphoma and these variables were detected using appropriate statistical methods. The significance level was set at p ≤ 0.05. Time series analysis was used to determine the trend of lymphoma frequency within 10 years of the study and to predict frequency until 2030.

RESULTS

Lymphomas constituted 2.86% of oral and para-oral lesions. Non-Hodgkin lymphoma was more common than Hodgkin lymphoma. Patients with non-Hodgkin lymphoma showed a higher median age than patients with Hodgkin lymphoma (p = 0.001). Non-Hodgkin lymphoma was more prone to occur intra-orally (p = 0.014). No statistical significance was observed in gender distribution between Hodgkin and non-Hodgkin lymphoma. Even though no specific time trend was observed from 2010 to 2019, forecasting for frequency of lymphomas through 10 years (2020 to 2030) showed a predicted increase.

CONCLUSIONS

The findings of this study were consistent with majority of other studies held in various geographic regions. The study revealed that frequency of oral and para-oral lymphomas in Cairo governorate is expected to rise; hence, oral pathologists should be more clinically suspicious and expect to encounter these lesions more in their practice within the upcoming years.

Subtype distribution of lymphomas in northwestern Iran: a retrospective analysis of 659 cases according to World Health Organization classification

Background

The distribution of lymphoma subtypes differs strikingly by geographic variations. However, there is limited information on this research in northern Iran. This study aims to evaluate the incidence, subtype, age, sex, and extranodal distribution of lymphomas diagnosed according to the latest WHO classification in a large referral center in northwest Iran.

Methods

In a retrospective study, the medical records of all patients with a diagnosis of lymphoma made between 2018 and 2021 were retrieved from the pathology archive of Imam Reza Medical Center, Tabriz. Lymphoma diagnosis was also made based on the appreciation of morphologic and immunophenotypic features and genetic characteristics in the context of clinical presentation.

Results

This study includes a total of 659 patients with lymphoma diagnosed from 2018 to 2021. The number of lymphoma patients were increased each year, with 51 (7.7%), 96 (14.6%), 244 (40.7%), and 268 (40.7%) reported from 2018 to 2021, respectively. 59% of the patients were men. The participants’ mean age was 50.5 ± 19.8 years, while the mean age at diagnosis was 49.3 ± 19.6 years. 2.1% were precursor lymphoid neoplasm, 61.6% were mature B cell neoplasm, 8.8% were mature T cell neoplasm, and 27.5% were Hodgkin lymphoma. The most prevalent subtype of mature B-cell lymphoma was DLBCL (55.1%), followed by SLL (18.7%). Extranodal involvement was seen in 40.5% of all cases.

Conclusion

The subtype distribution of lymphomas in northwest Iran is reported and compared with studies all over the world and inside Iran.

Epstein-Barr virus prevalence among subtypes of malignant lymphoma in Rwanda, 2012 to 2018

Few data exist on Epstein-Barr virus (EBV) prevalence across the full spectrum of lymphoma subtypes, particularly in sub-Saharan Africa. The objective of our study was to test the presence of EBV in a nationally representative sample of malignant lymphomas diagnosed in the Butaro Cancer Center of Excellence (BCCOE) in Rwanda. Of 102 Hodgkin (HL) and 378 non-Hodgkin lymphomas (NHL) diagnosed in BCCOE between 2012 and 2018, 52 HL and 207 NHL were successfully tested by EBV-encoding RNA in situ hybridization. EBV prevalence was 54% in HL, being detected in all classical HL subtypes: mixed-cellularity (n = 3/8), nodular-sclerosis (n = 7/17) and lymphocyte-rich (n = 2/3). EBV prevalence was 9% in NHL, being 10% among 158 B-cell NHL, 3% among 35 T-cell NHL and the single NK-cell NHL was EBV-positive. Among B-cell NHL, EBV was present in the majority of Burkitt (n = 8/13), and was also rarely detected in follicular (n = 1/4) and acute B-cell lymphoblastic (n = 1/45) lymphomas. Five of the 45 (11%) diffuse large B-cell lymphomas (DLBCLs) were EBV-positive, including three out of five plasmablastic lymphoma (PBL). Of 39 HL and 163 NHL of known human immunodeficiency virus (HIV) status, 2 (5%) and 14 (9%) were HIV-positive, respectively, of which only four were also EBV-positive (2 PBL, 2 HL). In summary, we report rare regional-level data on the association of EBV with classical HL, Burkitt and DLBCLs, and report sporadic detection in other subtypes possibly related to EBV. Such data inform the burden of disease caused by EBV and can help guide application of future advances in EBV-specific prevention and therapeutics.

Circulating long non-coding RNAs HOTAIR, Linc-p21, GAS5 and XIST expression profiles in diffuse large B-cell lymphoma: association with R-CHOP responsiveness

The reliable identification of diffuse large B-cell lymphoma (DLBCL)-specific targets owns huge implications for its diagnosis and treatment. Long non-coding RNAs (lncRNAs) are implicated in DLBCL pathogenesis; however, circulating DLBCL-related lncRNAs are barely investigated. We investigated plasma lncRNAs; HOTAIR, Linc-p21, GAS5 and XIST as biomarkers for DLBCL diagnosis and responsiveness to R-CHOP therapy. Eighty-four DLBCL patients and thirty-three healthy controls were included. Only plasma HOTAIR, XIST and GAS5 were differentially expressed in DLBCL patients compared to controls. Pretreatment plasma HOTAIR was higher, whereas GAS5 was lower in non-responders than responders to R-CHOP. Plasma GAS5 demonstrated superior diagnostic accuracy (AUC = 0.97) whereas a panel of HOTAIR + GAS5 superiorly discriminated responders from non-responders by ROC analysis. In multivariate analysis, HOTAIR was an independent predictor of non-response. Among patients, plasma HOTAIR, Linc-p21 and XIST were correlated. Plasma GAS5 negatively correlated with International Prognostic Index, whereas HOTAIR positively correlated with performance status, denoting their prognostic potential. We constructed the lncRNAs-related protein-protein interaction networks linked to drug response via bioinformatics analysis. In conclusion, we introduce plasma HOTAIR, GAS5 and XIST as potential non-invasive diagnostic tools for DLBCL, and pretreatment HOTAIR and GAS5 as candidates for evaluating therapy response, with HOTAIR as a predictor of R-CHOP failure. We provide novel surrogates for future predictive studies in personalized medicine.

Diffuse large B-cell lymphoma: An institutional analysis

Introduction:

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin's lymphoma. We conducted a retrospective study to analyze the clinicopathological characteristics, cell of origin, response to therapy, and the outcome of patients with DLBCL.

Materials and Methods:

This was a retrospective study which included all patients with DLBCL registered at our center, between May 1, 2013, and July 31, 2015. The data regarding demography, clinical presentation, histopathology, stage, prognostic index, treatment, and treatment-related outcome were collected from prospectively maintained clinical case records of the patients.

Results:

In the study, we included 267 patients. The median age is 49 (20–81) years with male: female ratio of 2:1. B symptoms were seen in 124 (45%) of patients. Early Stages (I and II) were seen in 130 (52%) patients, while advanced Stages (III and 1V) were seen in 119 (48%) patients. Bulky disease (>7.5 cm) was seen in 30% of cases, and bone marrow was involved in 12%. Extranodal involvement is present in 35% of cases. Cell of origin data was available in 160 (60%) of cases, of which 88 (55%) were germinal center and 72 (45%) were activated B cell in origin. The distribution according to the international prognostic index (IPI) was as follows: low risk 40%, intermediate risk 45%, and high risk in 15%. Rituximab was used in 45% of cases. The overall response rate was 84% with a complete response (CR) rate of 70.5%. The CR rates were better with RCHOP compared with CHOP (77% vs. 61.5%, P = 0.001) and good-risk IPI (83.3% vs. 65.2%, P < 0.001) compared with intermediate- and high-risk IPI. Median follow-up period was 24 months, and 2-year event-free survival (EFS) was 70%. The presence of B symptoms, high IPI, failure to attain CR, poor PS, and nonrituximab-based chemotherapy were significantly associated with lower EFS.

Conclusions:

This is the first study from India, which investigated the impact of chemotherapy with or without rituximab in context of cell of origin. Adding rituximab to CHOP showed better response rate and EFS irrespective of cell of origin.

Extranodal lymphoma arising within the maxillary alveolus: a systematic review

Objectives

Extranodal lymphomas affecting the head and neck infrequently arise within the jaw bones. Although clinical examination and conventional radiography may initially suffice for such lesions arising within the mandible, those arising within the maxillary alveolus generally require cross-sectional imaging because of the complex anatomy of this region. This study was performed to determine the prevalence, demographic characteristics, and clinical presentations of these lesions and the imaging modalities used for their diagnosis.

Study design

A systematic review (SR) on case series and another SR on case reports were performed to investigate the demographic, clinical, and radiological features of extranodal lymphomas arising within the maxillary alveolus.

Results

Most case series were derived from just four nations, whereas the case reports were derived from a wider range of ethnicities. The more detailed case reports significantly reported at least one imaging modality. Most patients were aware of their lesions for nearly 2 months before presentation. The most frequent symptom was swelling. Most case reports included a provisional diagnosis, the most frequent of which was dental infection followed by squamous cell carcinoma.

Discussion

Extranodal lymphomas arising within the maxillary alveolus were sufficiently frequent in four communities to be reported in two or more case series, and the occasional single case report indicated that such lesions are more widespread globally. Although the SR on case series revealed differences in the relative period prevalence and maxillary/mandibular ratio, the SR on case reports revealed details of the clinical presentation and imaging modalities used.

Spectrum of lymphoma in Bahrain. A retrospective analysis according to the World Health Organization classification

Objectives:

To determine the spectrum of various types of lymphoma in Bahrain according to the latest World Health Organization classification criteria.

Methods:

A retrospective review was conducted for all new lymphoma cases diagnosed at Salmaniya Medical Complex, Manama, Bahrain during the period from January 2010 to December 2015.

Results:

Two hundred and twenty-one new cases of lymphoma in Bahraini patients were diagnosed in the study period. Eighty patients had Hodgkin lymphoma, 140 had non-Hodgkin lymphoma, and one patient had composite lymphoma. In the Hodgkin lymphoma group, nodular sclerosis type was the most frequent type (48.75%), followed by mixed-cellularity type (27.5%), and nodular-lymphocyte predominant type (16.25%). In the non-Hodgkin lymphoma group, 124 (88.6%) cases were B-cell lymphomas, while the remaining were T-cell lymphomas. Diffuse large B-cell lymphoma was the most frequent type of non-Hodgkin B-cell type lymphoma (55.7%), followed by follicular lymphoma (10%).

Conclusion:

The distribution of lymphoma in Bahrain is similar to neighboring Middle East countries with a predominance of Hodgkin lymphoma and diffuse large B-cell lymphoma.

The utility of bone marrow sampling in the diagnosis and staging of lymphoma in South Africa

INTRODUCTION

The bone marrow biopsy (BMB) is a diagnostic and staging tool in lymphoma that remains practically useful and relevant in resource-constrained settings, despite restricted applications in international staging guidelines, which favour less invasive nuclear medicine techniques.

METHODS

Retrospective laboratory data review of BMBs in adult lymphoma patients from 2005 to 2010 to determine subtypes, rates of bone marrow involvement (BMI), human immunodeficiency virus (HIV) seroprevalence and CD4 counts, trephine length and additional findings.

RESULTS

A total of 1215 BMBs reported in lymphoma included 759 newly diagnosed patients, with BMI in 43.6% of non-Hodgkin lymphoma (NHL) overall, 28.9% of high-grade B subtypes and 35.7% of Hodgkin lymphoma (HL). HIV seroprevalence was 38.8%, 53.0% and 33.9% in the 3 respective groups. There was a statistical association between BMI and HIV seropositivity in Burkitt lymphoma and HL, and BMI and CD4 count in HIV-related HL. Over 10% (n = 79) of new lymphoma cases were diagnosed by BMB with ancillary tests. Occasional histological discordance and transformation were reported in NHL. Focal/unilateral BMI was uncommon. Bilateral BMB and biopsy length exceeding 26 mm did not improve BMI detection.

CONCLUSION

In the South African public sector, high HIV prevalence leads to a different lymphoma pathology profile from the developed world. High BMI rates are encountered. Here, and in similar resource-constrained settings, international lymphoma staging guidelines can be logistically challenging and unaffordable. BMB remains useful in the staging and diagnosis of lymphoma. Unilateral sampling with a processed trephine length of at least 26 mm is recommended.

Non-Hodgkin lymphoma in the developing world: review of 4539 cases from the International Non-Hodgkin Lymphoma Classification Project

The distribution of non-Hodgkin lymphoma subtypes varies around the world, but a large systematic comparative study has never been done. In this study, we evaluated the clinical features and relative frequencies of non-Hodgkin lymphoma subtypes in five developing regions of the world and compared the findings to the developed world. Five expert hematopathologists classified 4848 consecutive cases of lymphoma from 26 centers in 24 countries using the World Health Organization classification, and 4539 (93.6%) were confirmed to be non-Hodgkin lymphoma, with a significantly greater number of males than females in the developing regions compared to the developed world (P<0.05). The median age at diagnosis was significantly lower for both low- and high-grade B-cell lymphoma in the developing regions. The developing regions had a significantly lower frequency of B-cell lymphoma (86.6%) and a higher frequency of T- and natural killer-cell lymphoma (13.4%) compared to the developed world (90.7% and 9.3%, respectively). Also, the developing regions had significantly more cases of high-grade B-cell lymphoma (59.6%) and fewer cases of low-grade B-cell lymphoma (22.7%) compared to the developed world (39.2% and 32.7%, respectively). Among the B-cell lymphomas, diffuse large B-cell lymphoma was the most common subtype (42.5%) in the developing regions. Burkitt lymphoma (2.2%), precursor B- and T-lymphoblastic leukemia/lymphoma (1.1% and 2.9%, respectively) and extranodal natural killer/T-cell lymphoma (2.2%) were also significantly increased in the developing regions. These findings suggest that differences in etiologic and host risk factors are likely responsible, and more detailed epidemiological studies are needed to better understand these differences.