Patterns of lymphoma in Misan city, Iraq: A retrospective observational study

Introduction

The term lymphoma refers to a heterogeneous group of neoplasms that originate from lymphoid cells. The majority (85%) of lymphomas originate from mature B-cells, and 15% derive from the T-cell lineage¹. Historically and clinically, lymphomas have been divided into two groups, Hodgkin’s lymphoma (HL) and non-Hodgkin’s lymphoma (NHL). HL is characterized by the presence of Reed–Sternberg cells, which arise in a single lymph node or chain of lymph nodes and typically spread in a stepwise fashion to anatomically contiguous nodes¹. The crude incidence of HL among Europeans is 2.3 per 100,000 individuals². Young adults aged 20 to 40 years are most commonly affected¹. Histologically, classical HL accounts for 95% of all HL cases¹. The subtypes of classical lymphomas include nodular sclerosis (the most common subtype, comprising 60–65% of cases), mixed cellularity (15–30%), lymphocyte-rich (5%), and lymphocyte-depleted (1%)^1,3. HL patients present with peripheral lymphadenopathy, with nodes that are not tender, and with no overlying skin changes^1,2. NHL are neoplastic transformations of mature B-, T-, or natural killer cells¹. In children, diffuse large B-cell lymphoma (DLBCL), Burkitt’s lymphoma, and lymphoblastic lymphoma are most common^2–4. DLBCL is the most common histological subtype in adults⁴. The incidence increases with age, while a family history of lymphoma, autoimmune disease, human immunodeficiency virus infection, hepatitis C virus seropositivity, and a high body-mass as a young adult have all been identified as risk factors of DLBCL^4,5.

Here, we describe a study designed to show patterns of lymphoma among patients in Misan who presented at our center. Since this group of neoplasms are curable diseases, we need to obtain more information about them to get a significant and timely picture about the current lymphoma situation in Iraq, and in Misan in particular.

Methods

Setting

The study was conducted at Al-Shifaa Oncology Center, Al-Sadder Teaching Hospital, Faculty of Medicine, Misan University, Misan city, Iraq, from 1 April 2016 to 30 April, 2018 (Figure 1). The recruitment dates began on the tenth day of each month and continued to the thirtieth day of that month. The period from the first day of the month until the ninth day was the time of patient follow-up. Data were collected on the last day of each month of the study.

Figure 1. Al-Shifaa Oncology Center, Al-Sadder Teaching Hospital at the Faculty of Medicine.

Imagery ©2019 Maxar Technologies.

Results

All 80 participants included in this study were examined for eligibility and completion of follow-up. The mean age (±SD) of participants was 36±12.8 years. Half of the participants were in the 31–60 year age group, 24 (30%) of participants were aged >60 years, and just 16 (20%) belonged to the 10–30 year age group. Most participants (53; 67.5%) lived in rural areas, while 27 (32.5%) lived in urban regions. The majority of patients were employed (58; 72.5%). The male to female ratio was 1.5:1 (48 males and 32 females).

NHL was three-times more prevalent than HL, with 60 (75%) and 20 (25%) cases, respectively. Participants most frequently presented with stage IV, in 34 (42.5%) of cases, followed by stage III in 24 (32.5%), stage II in 12 (15%), and stage I in 8 (10%) cases. The classical subtypes of HL were most common, occurring in 14 (70%) cases compared with 6 (30%) cases who had nodular subtypes. The DLBCL subtype was most common among NHL subtypes, being recorded in 44 (73.3%) of cases. Classical HL was subdivided into nodular sclerosis (2; 14.3%), lymphatic-rich subtype (4; 28.6%), and mixed cellularity (8; 57.1%) (Table 1).

Discussion

In our study, HL and NHL were recorded in 25% and 75% of cases, respectively, which is consistent with the results of a study conducted in Erbil city, in the north of Iraq⁶. The majority of HL cases presented as the classical subtype (70%), while 30% of cases encountered were of the nodular subtype (30%). The subtypes of classical HL included the nodular sclerosis (NS) subtype (14.3%) and the lymphocyte-rich subtype (28.6%), although the majority of cases comprised the mixed cellularity subtype (57.1%). The most frequent histological subtype of HL was mixed cellularity, which differs from earlier reports from the north of Iraq^5,6, but is consistent with earlier reports from nearby countries and India^7–17. This changing pattern differs from more recent reports from Saudi Arabia, Jordan, United Arab Emirates (UAE), and Kuwait, where higher relative rates of NS HL were reported, approaching levels seen in the USA and in European countries^12–17.

With regard to NHL subtypes, we found that the majority comprised DLBCL, followed by mantle cell, follicular cell, peripheral T-cell, and Burkitt’s lymphoma. According to WHO classifications, DLBCL was also the most common diagnosis worldwide, at 52.2%, followed by T-cell rich lymphoma¹². The relative proportion of DLBCL seen in the current study is almost twice the proportion seen in the USA and Europe, and is much higher than the proportion reported in India^2,4,17,18, but is closer to figures reported from UAE¹⁴, Kuwait¹⁵, Jordan¹³, and Turkey¹⁹.

We found that the majority of lymphoma cases occurred in those aged 31 to 60 years, which was the same as findings in the USA and other countries^15,18–20.

The majority of cases in our study presented at stage III or stage IV. Stage IV comprised 42.5% of cases and stage III 32.5%, while the remainder were stage II (15%) and stage I (10%). These results are in agreement with the results of a study by Robert et al.²¹.

Limitations of this study include that it was a single-centre study, with a small number of participants, and the participants represent residents of the Misan government administrative area only.

Conclusions

This study showed that in Misan city, Iraq, lymphoma occurs most frequently among males. NHL is more common than HL, and the most common histopathology of HL is mixed cellularity, while DLBCL is the most common histopathology for NHL. Most cases presented with stage III or IV, which reflects delays in diagnosis, and decreases the chance of complete recovery, reflecting a more aggressive course and behavior of the disease.

Data availability

Zenodo: Lymphoma diseases patients patterns in Misan Government, http://doi.org/10.5281/zenodo.3458806²².