|Year : 2021 | Volume
| Issue : 4 | Page : 266-272
Distribution pattern and prevalence of haematological cancers among adults in Abakaliki, South-Eastern Nigeria
Ngozi Immaculata Ugwu1, Augustine Ejike Okoye1, Collins N Ugwu2, Festus E Iyare3, Felix Osogu Edegbe3, Gabriel Chima Ugwu4, Ejike Felix Chukwurah5, Ikeagwulonu Chinaza Richard6, Davidson Okwudili John7, Ugochukwu Uzodimma Nnadozie8, Emmanuel Uchechukwu Nwokwu9
1 Department of Haematology and Immunology, Faculty of Basic Clinical Sciences, College of Health Sciences, Ebonyi State University, Abakaliki, Nigeria
2 Department of Internal Medicine, Faculty of Clinical Medicine, College of Health Sciences, Ebonyi State University, Abakaliki, Nigeria
3 Department of Morbid Anatomy, Faculty of Basic Clinical Sciences, College of Health Sciences, Ebonyi State University, Abakaliki, Nigeria
4 Department of Haematology and Transfusion Medicine, Alex Ekwueme Federal University Teaching Hospital, Abakaliki, Nigeria
5 Department of Medical Laboratory Science, Faculty of Health Sciences and Technology, Ebonyi State University, Abakaliki, Nigeria
6 Department of Chemical Pathology, Alex Ekwueme Federal Teaching Hospital, Abakaliki, Nigeria
7 Department of Physiotherap, Alex Ekwueme Federal Teaching Hospital, Abakaliki, Nigeria
8 Department of Surgery, Division of Plastic Surgery, Faculty of Clinical Medicine, College of Health Sciences, Ebonyi State University, Abakaliki, Nigeria
9 National Cancer Control Programme, Federal Ministry of Health, Abuja, Nigeria
|Date of Submission||10-Aug-2021|
|Date of Decision||22-Sep-2021|
|Date of Acceptance||25-Sep-2021|
|Date of Web Publication||29-Nov-2021|
Dr. Ngozi Immaculata Ugwu
Department of Haematology and Immunology, Faculty of Basic Clinical Sciences, College of Health Sciences, Ebonyi State University, Abakaliki
Source of Support: None, Conflict of Interest: None
Background: Haematological cancers are clonal diseases of the blood and blood-forming organs, with the distribution pattern not known in our locality. This study aimed to describe the distribution pattern and prevalence of haematological cancers among adults in Abakaliki, Nigeria. Materials and Methods: This was an 8-year retrospective study in which the hospital records/case notes of adult patients diagnosed and managed for haematological cancers from May 2012 to April 2020 were reviewed. Data obtained were analysed with the SPSS software, version 20. Results: One hundred and thirty-five cases of haematological cancers were included in the study, with 72 (53.4%) males and 63 (46.6%) females and male-to-female ratio of 1.1:1. The age range was 18–82 years, with a mean age of 49 ± 17 years. Lymphoid malignancies predominate more than myeloid (101 [74.8%] vs. 34 [25.2%]). The leukaemias were more predominant than the lymphomas and myeloma accounting for 48.2%, 36.3% and 7.4%, respectively. Chronic leukaemias were more common than the acute leukaemias with chronic lymphocytic leukaemia (CLL) being the most common accounting for 24.4% of haematological cancers. In general, non-Hodgkin's lymphoma (NHL) was the most common haematologic cancer accounting for 35 (25.9%), followed by CLL 33 (24.4%), chronic myeloid leukaemia (CML) 17 (12.6%), Hodgkin's lymphoma (HL) 14 (10.4%) and multiple myeloma (MM) 10 (7.4%). Others include acute lymphoblastic leukaemia (ALL) 9 (6.7%) and acute myeloblastic leukaemia (AML) 6 (4.4%). Myelodysplastic syndrome (MDS) and polycythaemia vera (PV), each contributed 3% while myelofibrosis (MF) and essential thrombocythaemia (ET) contributed 1.5% and 0.7%, respectively. Conclusion: This study has shown that haematological cancers are not uncommon in our locality with NHL being the most common, followed by CLL, CML, HL, MM, ALL, AML, MDS, PV. MF and ET in that order. The burden of haematological cancers in Ebonyi State, Nigeria is therefore significant and should be prioritised in health-care policy formulation and management.
Keywords: Haematological cancers, leukaemia, lymphoma, myeloma, prevalence
|How to cite this article:|
Ugwu NI, Okoye AE, Ugwu CN, Iyare FE, Edegbe FO, Ugwu GC, Chukwurah EF, Richard IC, John DO, Nnadozie UU, Nwokwu EU. Distribution pattern and prevalence of haematological cancers among adults in Abakaliki, South-Eastern Nigeria. Niger Postgrad Med J 2021;28:266-72
|How to cite this URL:|
Ugwu NI, Okoye AE, Ugwu CN, Iyare FE, Edegbe FO, Ugwu GC, Chukwurah EF, Richard IC, John DO, Nnadozie UU, Nwokwu EU. Distribution pattern and prevalence of haematological cancers among adults in Abakaliki, South-Eastern Nigeria. Niger Postgrad Med J [serial online] 2021 [cited 2022 May 20];28:266-72. Available from: https://www.npmj.org/text.asp?2021/28/4/266/331533
| Introduction|| |
Cancer is a group of diseases which occurs when abnormal cells grow uncontrollably and spread to other tissues and organs. Cancer can develop anywhere in the body and is named for that part of the body where it started, including haematological cancers. Cancer is increasingly being recognised as a public health problem. It has an unfavourable impact on the social and economic well-being of the affected populations, putting enormous burden on the afflicted individuals and their families financially, medically and psychologically as well as on the global scarce health-care resources. Despite the growing burden, cancer is not receiving enough attention by policy makers, particularly in developing countries. This could be due to the lack of awareness about the burden and magnitude of the disease, scarce resources, burden of communicable diseases and other demanding public health issues. It is necessary, therefore, to study the distribution pattern of haematological cancers among adults in our environment.
Haematological malignancies are group of cancers that arise from a malignant transformation of cells of the bone marrow or lymphatic system. They are often associated with chromosomal abnormalities and usually clonal in origin. The cause of haematological cancers and cancers in general is not usually known, but some risk factors have been associated with the development of these cancers including immunosuppression or immunodeficiency states, microbial agents (such as Epstein − Barr virus [EBV], Human T-lymphotrophic virus human immunodeficiency virus and Helicobacter pylori), These immune-related risk factors are thought to contribute to a complex interplay of genetic damage in somatic cells due to mutations, chronic antigenic stimulation, cytokines and other signalling protein dysregulation. Other factors include ionising radiation and chemicals (such as benzene, pesticides, smoking, etc.). Studies of these environmental risk factors and some social behaviours are therefore of immense clinical importance.
Haematological cancers are found globally and can occur at all ages and in both sexes. There is variation in the pattern of clinical presentation, and this depends on the nature and severity of the disease. There are two broad divisions of haematological cancers according to their cell lineage into lymphoid and myeloid cancers. Lymphoid malignancies are sub-grouped into the lymphomas (Hodgkin's and Non-hodgkin's lymphoma [NHL]), chronic lymphocytic leukaemia (CLL), acute lymphoblastic leukaemia (ALL) and multiple myeloma (MM), whereas the myeloid malignancies include the acute myeloblastic leukaemia (AML), myelodysplastic syndrome, chronic myeloid leukaemia (CML) and myeloproliferative neoplasms. Lymphoma and leukaemia are the most common haematological cancers worldwide.
Haematological malignancies make up a fifth of the most commonly occurring cancers and the second leading cause of cancer mortality globally. In Europe and the USA, haematological malignancies comprise the fourth most common cancer. Haematological cancers accounted for 8.7% of cancer cases and 9.9% of cancer-related deaths in sub-Saharan Africa in 2008, with NHL being the 5th most common cancer in the region. Different rates of haematological cancers have been reported in the different parts of Nigeria, with NHL shown to be the third and fifth most common cancer in male and female, respectively. In a study conducted in a cancer registry in Southern Nigeria, haematologic cancers were reported among the five most common cancers with leukaemia contributing 4.3%. Another study conducted in Northern Nigeria reported a prevalence of 12.4%, with male preponderance and NHL as the most common haematologic cancer contributing 20.7%.
Because of the marked disparity in the social and physical environment in the different regions of the world, there may be significant differences in the epidemiology of haematological cancers. Although some studies on the prevalence and distribution pattern of haematological cancers have been done in some parts of Nigeria and abroad, no previous studies have been done on this issue in our locality. Thus, this study was aimed at determining the distribution pattern and prevalence of various haematological cancers, which are encountered among adults in Abakaliki, Nigeria.
| Materials and Methods|| |
Ethical approval for the study was obtained from the Research and Ethics Committee of Alex Ekwueme Federal University Teaching Hospital, Abakaliki with protocol number FETHA/REC/VOL 2/2019/181.
We conducted a retrospective study at the Alex Ekwueme Federal University Teaching Hospital Abakaliki over a period of 8 years (between May 2012 and April 2020). The hospital is a 700-bedded tertiary health institution that renders specialist care to its host community and environs as well as secondary health facilities in the state. It also serves as a referral centre for her neighbouring states such as Cross River, Benue, Abia, Enugu and Imo States.
Case-notes of all adult haematological cancer patients diagnosed and/or managed within the 8-year period were retrieved from the Medical Records and Haematology Department of our hospital. The cancer register of the histopathology department of the hospital was also consulted to include those who were diagnosed but were not managed in the hospital and those who passed on before their histology results were ready.
Adult was defined as ages of 18 years and above. Included in the study were those who had confirmed diagnoses made by either a consultant haematologist or histopathologist through morphology/histology with or without immunophenotyping, cytogenetics or molecular methods and the patients were at least 18 years at the time of diagnosis. Hospital records without definitive diagnosis or with incomplete data were excluded. Information collected from the case notes included age, sex, occupation, marital status and diagnosis.
Data generated from the study were analysed using IBM Statistical Package for the Social Sciences (SPSS) software, version 20 (IBM SPSS Inc. Chicago, IL, USA). Proportion, percentages and mean ± standard deviation were generated using the descriptive statistics. The results were presented in tables and charts.
| Results|| |
One hundred and thirty-five cases met the inclusion criteria and were included in the study. They were made up of 72 (53.4%) males and 63 (46.6%) females, with a male-to-female ratio of 1.1:1. The age range was 18–82 years, with a mean age of 49 ± 17 years. A higher proportion of them were married 97 (71.9%). Most of the patients were traders 40 (30.3%), followed by civil servants 33 (24.2%) and farmers 30 (22.2%) [Table 1].
According to cell lineage, lymphoid malignancies predominate more than myeloid (101 [74.8%] versus 34 [25.2%]) [Figure 1]. Among the three major groups of haematological cancers, the leukaemias were more predominant than the lymphomas and myeloma accounting for 48.1% of haematological cancers [Figure 2]. Among the lymphomas, NHL was more common than the Hodgkin's lymphoma (HL), contributing 25.9% of haematological cancers seen. Among the leukaemias, chronic leukaemias were more common than the acute leukaemias with CLL being the most common accounting for 24.4% of haematological cancers in this study.
In general, the distribution of the various haematological cancers recorded showed that NHL was the most common haematological cancer accounting for 35 (25.9%), followed by CLL 33 (24.4%), CML 17 (12.6%), HL 14 (10.4%), MM 10 (7.4%); AML 6 (4.4%), ALL 9 (6.7%), polycythaemia vera (PV) and Myelodysplastic syndrome (MDS) were 4 (3%) each [Figure 3].
|Figure 3: Distribution of the various haematological cancers. NHL – Non-Hodgkins lymphoma, HL – Hodgkins lymphoma, CLL - Chronic lymphocytic leukaemia, ALL – Acute lymphoblastic leukaemia, CML - Chronic myelocytic leukaemia, AML – Acute myeloblastic leukaemia, MM – Multiple myeloma, PV – polycythaemia vera, MDS – Myelodysplastic syndrome, ET – Essential thrombocythaemia, MF – Myelofibrosis|
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The mean age of distribution for the various haematological cancers is shown in [Table 2]. HL, CML and ALL were found more in young adults, whereas CLL and MM were found mainly in middle age and in the elderly.
|Table 2: Frequency and age distribution of various haematological cancers|
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Sex distribution for the various haematological cancers showed that more males were affected than females. However, when haematological cancers were considered individually, there was marginal female preponderance for CLL, NHL, AML, MM and MDS [Table 3].
|Table 3: Frequency and gender distribution of various haematological cancers|
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| Discussion|| |
This study found that haematological cancers are not uncommon in our locality. According to cell lineage, lymphoid haematological cancers were thrice more common than myeloid malignancies. Previous studies have also reported that lymphoid haematologic cancers are more common than those of myeloid cell lines.,, Among the lymphoid lineage, NHL, CLL and HL were the most common in that order while CML and AML were the most common among cancers of the myeloid cell lines. Similar findings have also been reported by previous studies.,
In general, NHL was found to be the most common haematological cancer accounting for 25.9%. This was in keeping with the findings by Nwannadi et al. and Babatunde et al., who also found NHL as the most common haematological cancer. This was however contrary to the report of the study conducted in Markurdi Nigeria by Onoja et al., who found CLL to be the most common haematological cancer. Another study conducted in Eritrean, East Africa reported acute leukaemia as the most common haematological cancer. The difference in the findings may be due to the differences in the method of diagnosis of the haematological cancers. Bone marrow aspiration was the only method of diagnosis in their studies, whereas our study included haematological cancers diagnosed with both bone marrow aspiration and tissue biopsy.
CLL was the next in the frequency to NHL in this study, accounting for 24.4% of haematological cancers seen. This was followed by CML accounting for 12.6%. This is in parity with previous findings in the different parts of Nigeria., However, contrary findings have been reported by a study conducted in Pakistan, where AML was reported as the commonest haematological cancer, followed by ALL and CLL. In addition, Sant et al. in a study conducted in Europe found plasma cell neoplasms as the most common haematological cancers, followed by NHL and HL. Variation in the distribution pattern of haematological cancers at different geographical regions may be due to the differences in environmental exposure to risk factors such as agricultural use of pesticides, weed killers and other chemicals. It may also be due to variation in health-seeking behaviour of people from different regions where patients present to the hospital for medical care with prompt diagnosis in some places.
Among the three main groups of haematologic cancers, leukaemias were found to predominate more than lymphomas and myeloma. Among the leukaemias, chronic leukaemias were found to be more prevalent than acute leukaemias with CLL and CML, contributing 24.4% and 12.6%, respectively. This collaborates with the findings from previous studies which also reported preponderance of chronic leukaemias compared to acute leukaemias.,, The reason may be because chronic leukaemias are usually gradual in onset so it usually give the patient enough time to have presented to the hospital while acute leukaemias are usually sudden in onset and may not give the patient the opportunity to present to the hospital. Moreover, some patients with acute leukaemias may have succumbed to the disease before presenting to the hospital for specialist management. Among the chronic leukaemias, CLL was found to be more prevalent than CML contributing almost double the cases of CML seen within the period. This collaborates with the observations of previous studies which also reported CLL to be the most common type of leukaemia., Conversely, Babatunde et al. in a study conducted in Ilorin, North-western Nigeria reported that the prevalence of CML was more than that of CLL. This brings to mind the issues of social and ethnic/racial paradigm of the disease. However, reports from Europe also stated that CLL is the most common type of leukaemia in Western countries.
For the acute leukaemias, ALL was more prevalent than AML, contributing 6.7% while AML accounted for 4.4%. This finding was similar to what has been reported by previous studies., However, the observation is at variance with equal percentages of the leukaemias that was reported in a study at Ilorin North-west Nigeria.
For the lymphomas, NHL was found to predominate more than the HL and accounted for almost three times the cases of HL seen. Previous studies have also reported NHL to be more common than HL., HL was found to affect mainly the young adults with the highest peak at 18–29 years. This is at variance with the findings of previous studies which reported bimodal peak at 20–29 years and second peak at 40–49 years., The differences may be due to variation in exposure to infection with EBV. Association of HL with malaria endemicity may also contribute to the differences in the epidemiological pattern.
This study also found that MM contributed 7.4% of haematological cancers. This value is similar to the report of Nwagu et al., in Ekpoma South-South Nigeria, and Hasan et al., in Senegal but higher value has been reported by Akaba et al., in Calabar Nigeria. Lower prevalence has also been reported in Maiduguri, Northern Nigeria. Differences in the values of MM reported by authors in different geographic areas among different populations may be related to environmental and genetic factors.
Myelodysplastic syndrome (MDS) contributed 3% of haematologic cancers seen in this study. MDS is usually a diagnosis of exclusion and so high index of suspicion is required for its diagnosis as it commonly presents as refractory anaemia which may be mistaken for other causes of chronic anaemia. Similar prevalence of MDS has also been reported by previous studies., Lower prevalence has been reported by Otu and Ejikeme and Kagu, et al. The lower prevalence recorded in their studies may be due to the fact that their study populations included all patients with haematologic cancers both adult and children while this study included only adult patients. Onoja et al. and Belai et al. recorded higher prevalence which may be due to their method of diagnosis. Their study included only haematologic cancers diagnosed with bone marrow aspiration while this study included haematologic cancers diagnosed with both bone marrow aspiration and tissue biopsy.
PV contributed 3% of the haematologic cancers seen in this study. Similar findings were also reported by Otu and Ejikeme in Abuja, Northern Nigeria and Khan, et al. in Pakistan while lower values were reported by Nwagu, et al. in Southern Nigeria. This study also found that essential thrombocythaemia (ET) contributed 0.7% while myelofibrosis (MF) contributed 1.5%. Previous studies have also reported that these cancers contributed a small percentage to the overall haematological cancers seen.,, Although a study in Pakistan reported slightly higher values for MF, another study in Nepal also reported a higher value for ET. Variation in the prevalence of these cancers at different geographical locations may be due to environmental factors.
Majority of the patients in this study were married. This is not surprising considering the fact that our study population was adults and the mean age at diagnosis was 49 ± 17 years. This is expected because people get married as their age advances. Again, most of the malignancies occurred in people that were 40 years and above, although the age range was 18–82 years, with individual cancers having varying peak ages. This corroborates with the findings of previous studies, and is biologically explainable due to the multiple hit theory, which suggests that the cumulative effect of genetic assault manifest over time.
This study also found that most of our patients were gainfully employed and were mainly traders and civil servants. These are people who can afford the cost of treatment for hospital care and specialist management. In Nigeria, many patients pay out-of-pocket for medical care as only a few have been captured by the health insurance scheme. Therefore, the unemployed and the poor would not be able to afford the cost of medical care., They would rather manage themselves at home and would not present to the hospital for proper care.
Different types of haematological cancers were observed to occur more commonly in particular age groups, with different cancers showing different mean ages. NHL was found to affect mainly patients that were of middle age and elderly while HL affected people of the younger age group (<30 years). CLL, MDS, MF and MM were also found to affect mainly the middle aged and the elderly while CML, AML and ALL affected people of the middle age and young age groups. These observations are similar to the pattern that had been reported from other studies in Africa.,, However, CML and HL have been shown to be common in middle aged and elderly people in the United States of America.
In this study, more males were observed to be affected more than females generally. Although there was slight female preponderance for MM, CLL, AML and MDS when haematological cancers were considered individually, as also reported by Akaba, et al. in Calabar, Southern Nigeria but at variance with the report from the UK which showed male preponderance even in those haematologic cancers individually. Previous studies have also reported that many haematological cancers occur more in males than females,,,, although Nwagu et al. in Southern Nigeria reported slight female predominance. The higher prevalence of haematological cancers among males could be attributed to the fact that males are more exposed to occupational agents that predispose to the development of haematological cancers. Male preponderance could also be related to lifestyle as a result of excessive alcohol consumption and smoking.
Limitations for the study
The strength of this study lies in the fact that it was the very first step in understanding the distribution pattern and prevalence of haematologic cancers among adults in Ebonyi State, Nigeria. However, limitations of the study include the fact that it was a retrospective study and therefore information bias is inevitable. A few cases may have been missed out due to the lack of proper documentation, missing data and improper record keeping. In addition, the diagnosis of haematologic cancers in our centre was made mainly with morphology. The absence of other diagnostic methods such as cytogenetic studies or flow cytometry was also important limitations of the study as some cancers may have been wrongly diagnosed and classified.
| Conclusion|| |
This study has shown that haematological cancers are not uncommon in our locality with NHL being the most common, followed by CLL, CML, HL, MM, ALL, AML, MDS, PV, MF and ET in that order. All age groups were affected by haematologic cancer with a mean age of 49 years. Haematological cancers of the lymphoid lineage predominate more than the myeloid cell lines and contributed about three quarter (74.8%) of haematological cancers seen. Among lymphomas, NHL was found to be more common than the HL, contributing 25.9% of haematological cancers. Among the three major groups of haematologic cancers, leukaemias were more common than the lymphomas and myelomas. Among leukaemias, chronic leukaemias were more common than the acute leukaemias with CLL being the most common, contributing 24.4% of haematological cancers in this study. Overall, males were more affected with haematological cancers than females. This study has shown that the burden of haematological cancers in Ebonyi State, Nigeria is significant and should be prioritised in health-care policy formulation and management. It would also serve as a tool for raising awareness on the disease burden as well as a baseline for further studies.
We wish to acknowledge the support and assistance of the staff in the Departments of Medical Records, Haematology and Morbid Anatomy, Alex Ekwueme Federal University Teaching Hospital, Abakaliki Nigeria, during this study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]