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RESEARCH 

Epidemiology of Prostate Cancer in 
Nigeria: Observations at Lagos State 
University Teaching Hospital 
⃰Emiogun  Festus Edobor, Williams Oluwaseun Olatunde, Obafunwa John Oladapo  

Department of Pathology and Forensic Medicine, Lagos State University Teaching Hospital, 1 – 5 Oba 
Akinjobi Way, Ikeja, Lagos, Nigeria. 

*Corresponding author:  E-mail: edos2infinity@yahoo.com 

ABSTRACT 
Prostate cancer is a leading cause of morbidity and mortality among men, especially of African 
descent. Over the years, there has been relative paucity of research work on the subject of prostate 
cancer in sub-Saharan Africa. The objective of the study is to examine records of prostate cancers 
diagnosed at Mayo Height laboratory, Lagos State University Teaching Hospital, Lagos, Nigeria 
between January 2015 and June 2018, with a view to studying the epidemiological variables and 
pattern seen. Histopathological slides were retrieved and reviewed; relevant data were extracted from 
the Laboratory Information Systems, Laboratory Requisition Forms and the Hospital records where 
necessary. The data were statistically analyzed. 

A total of 333 cases of prostate cancer were diagnosed during the study period, representing 46.4% of 
all prostate specimens received. The median age of the patients at diagnosis was 70 years, with the 
lowest recorded age being 50 years, while the highest age was 90 years. Individuals in the 7th decade 
of life (61-70 years) were the most commonly affected. Overwhelming number of cases (97.3%) were 
diagnosed based on trucut biopsy specimens, compared to open prostatectomy specimen. Majority of 
the cancers were histologically adenocarcinomas (97.3%) and majority of the tumours were of high 
grade (Gleason grade 5) representing 37.5%. Prostate cancer is an obvious scourge in Nigeria. It is 
commonly seen in the 7th decade of life. Majority of the patients had high grade adenocarcinoma. 

KEYWORDS: Prostatic carcinoma, histopathology, epidemiology, Lagos, Nigeria. 
 

Citation: Emiogun FE, Williams OO, Obafunwa JO (2019) Epidemiology of Prostate Cancer in Nigeria: 
Observations at Lagos State University Teaching Hospital. Cancer Health Disparities 4: e1-e-9. 
doi:10.9777/chd.2019.1003 

 
 
 



 
 
 
 
 

 
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INTRODUCTION 

Prostate cancer is rated the second most common 
cancer and sixth leading cause of cancer deaths 
among men globally, making it an important 
cause of morbidity and mortality (Ferlay et al., 
2012). Prostate cancer is the most frequent cancer 
in men in the United States. African American 
ancestry, family history, and increased age are the 
primary risk factors for prostate cancer (Haas et al., 
2008). Prostate cancer is the most common 
urological malignancy affecting black Africans 
(Magoha, 2007 and Baade et al., 2009)   

The incidence of prostate cancer has tripled during 
the past decade, chiefly because of increased 
diagnosis with the widespread use of serum 
Prostate-Specific Antigen (PSA) testing, digital 
rectal examination (DRE), transrectal ultrasound 
and needle biopsy of the prostate (Oluwole, et al., 
2015 and Amin et al., 2005). 

Cancer of the prostate is currently the most 
frequent malignancy of the adult Nigerian male 
with increasing incidence annually. Studies on 
prostate cancer from the Ibadan Cancer Registry 
showed that the relative ratio frequency for 
prostate cancer when compared to other male 
cancers increased from 4.45% to 10.5% over the 
last three decades (Okolo et al., 2008 and 
Ogunbiyi et al., 1999). 

Most cases of prostate cancer occur after the age 
of 50 years and there is an exponential increase in 
incidence which peaks in the 70s. Worldwide, 
about three-quarters of all cases occur in men 
aged 65 or more (WHO, 2004). Various histologic 
studies on prostate specimens taken in different 
centres across Nigeria have shown prostate cancer 
incidences ranging from 22.4% to 37.4% 

(Mohammed et al., 2003, Okeke et al., 2017 and 
Obiorah et al., 2011). 

The incidence of prostate cancer has also been 
shown to vary across various African countries to 
include Gambia 2.5 per 100,000, South Africa 30.8 
per 100,000 and Uganda 35.5 per 100,000 (Bah et 
al., 2001, Baab et al., 2014 and Parkin et al., 2010). 
The low incidence areas globally include the Asia-
Pacific region and North Africa with 3 per 100,000 
and 10.6 per 100,000 respectively (Baade et al., 
2013).  

The most common histologic type of prostate 
cancer type is adenocarcinoma with other 
histologic types being quite rare (Haaa et al., 
2008).  

The Gleason score system is the most widespread 
grading tool for prostate cancer. It is the system 
recommended by the 1993 WHO consensus 
conference on prostate cancer diagnosis due to its 
high reproducibility across different institutions 
(Murphy et al., 1994). It is one of the most reliable 
predictors of prostate cancer progression and 
survival (Seyed et al., 2004). The system is based 
on glandular architecture which is used to define 
five histological patterns or grades with decreasing 
differentiation (Gleason, 1966).  

This study aims to examine the pattern of prostate 
cancer seen among men of Nigerian descent. The 
finding in this study will enrich the understanding 
of the characteristics of prostate cancer among 
African men which in turn will guide further effort 
at curbing the scourge.   

MATERIALS AND METHODS 
Laboratory reports on all cases of prostate 
samples (core biopsies and prostatectomy 
submissions) were retrieved from the Laboratory 



 
 
 
 
 

 
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RESEARCH 

Information System at Mayo Heights Laboratory of 
the Lagos State University Teaching Hospital. The 
laboratory receives and process samples from the 
teaching hospital where the department is located. 
Samples are also received from across the General 
Hospitals within Lagos State, and many of the 
private hospitals. 

The formalin-fixed paraffin embedded samples of 
tissues of prostatic origin, and associated 
histological slides were retrieved from storage and 
reviewed independently by the authors to reach a 
consensus as to the diagnosis. Relevant clinical 
data were also retrieved from the requisition 
forms. Data were then specifically extracted for the 
malignant cases. Prostate cancer grading was 
done using the Gleason Score System. 

The data compiled were analysed and also 
where indicated, subjected to statistical analysis, 
utilizing SPSS statistical package software 
version 19. 

RESULTS 

A total of 717 prostate specimens were received in 
Mayo Heights Laboratory, Lagos State University 
Teaching Hospital, over a 42-month period 
between January 2015 and June 2018. Of this 
number, 333 were prostate cancers, representing 
46.4% (Table 1). The lowest age at diagnosis was 
50 years, while 90 years was the highest age 
recorded at diagnosis (Figure 1).  The mean age 
was 69 ± 8.0 years while the median age was 70 
(24 cases). The most frequent age group was 61 – 
70 years (141, 42.3%), followed by 71 – 80 years 
(112, 33.6%) while 26 (7.8%) was recorded for 
patients above 80 years. 

Table 1. Annual Distribution. 
Year Number Percentage 
2015 63 19.0 
2016 114 34.2 
2017 122 36.6 
2018 (6 months) 34 10.2 
Total 333 100 

 

 

Figure 1. Age at Diagnosis. 

0.0%
5.0%

10.0%
15.0%
20.0%
25.0%
30.0%
35.0%
40.0%
45.0%

50 – 60 61 – 70 71 – 80 Above 80 Not
stated

43 (12.9%)

141 (42.3%)

112 (33.6%)

26 (7.8%)
11 (3.4%)

Pe
rc

en
t

Age at Diagnosis



 
 
 
 
 

 
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Majority of the patients were Yorubas (247, 74.2%) 
followed by Ibos (77, 23.1%) while only 9 (2.7%) 
were from other ethnic groups (Table 2). 

Table 2. Ethnic distribution. 
Ethnic group Number of cases Percentage 
Yoruba 247 74.2 
Ibo 77 23.1 
Others 9 2.7 
TOTAL 333 100 

Prostate cancer diagnosis was made on 316 
(94.9%) trucut biopsy specimens, while 17 (5.1%) 
were prostatectomy specimens (Figure 2). 

 

Figure 2. Showing type of tissue for diagnosis. 

Majority (324, 97.3%) were diagnosed as 
adenocarcinoma; papillary carcinoma accounted 
for 7 (2.1%) of the cases, while clear cell carcinoma 
and mucinous carcinoma represented 0.3% each 
(Table 3). 

Table 3. Histological types. 
Type Number Percentage 
Adenocarcinoma 324 97.3 
Papillary carcinoma 7 2.1 
Clear cell carcinoma 1 0.3 
Mucinous carcinoma 1 0.3 

Adenocarcinomas were categorized according to 
the Gleason patterns observed. Figures 3-7 typifies 
Gleason patterns 1 to 5 as seen in this series. Most 
of the prostate cancers diagnosed at our Centre 

were Gleason grade 5 (high grade, Figs. 6 and 7) 
which accounted for 125 (37.5%) of all the 
tumours, while grade 3 (Fig. 4 and 5) was the least 
with 34 (10.2%). Low grade tumour (grade 1) was 
observed in 37 (11.1%) of the cases (Figures 3 and 
4). 

 

Figure 3. Photomicrograph (X 100, H&E) showing 
closely packed glands with little intervening stroma 
Prostatic adenocarcinoma Gleason pattern 1. 

 

Figure 4. Photomicrograph (X40 H&E) showing 
infiltrating small-sized distinct neoplastic glands 
with appreciable amount of intervening stroma. 
Prostatic adenocarcinoma Gleason pattern 2. 

94.9%

5.1%

Biopsy Prostatectomy



 
 
 
 
 

 
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RESEARCH 

 

Figure 5. Photomicrograph (X40 H&E) showing 
infiltrating, irregular small-sized neoplastic glands. 
Prostatic adenocarcinoma, Gleason pattern 3. 

 

Figure 6. Photomicrograph (X40 H&E) showing 
fused neoplastic glands forming a cribriform 

pattern. Prostatic adenocarcinoma Gleason pattern 
4. 

 

Figure 7. Photomicrograph (X100 H&E) showing 
sheet of neoplastic cells. Prostatic adenocarcinoma 
Gleason pattern 5. 

Grade 1 tumour was most commonly observed in 
the 50-60 years age group (11, 28.2%), while grade 
5 was most frequently seen in the 71-80 years 
group 

This study showed that the commonest number of 
prostate biopsy cores sent to our laboratory by 
Surgeons is 10 (11.2%). In some cases, as few as 2 
cores (2, 3.0%) and as many as 32 cores (1, 0.3%) 
were received (Table 5). 

Table 4. Association between grades and age (P = 0.380). 
 Age group in years (%) 

Gleason Grade 50 – 60 61 – 70 71 – 80 Above 80 
Grade 1 11 (28.2%) 14 (10.6%) 11 (11.7%) 1 (4.5%) 
Grade 2 4 (10.3%) 20 (15.2%) 10 (10.6%) 2 (9.1%) 
Grade 3 4 (10.3%) 16 (12.1%) 10 (10.6%)   3 (13.6%) 
Grade 4 5 (12.8%) 28 (21.2%) 19 (20.2%)   6 (27.3%) 
Grade 5 15 (38.5%) 54 (40.9%) 44 (46.8%) 10 (45.5%) 
Total 39 (100.0%) 132 (100.0%) 94 (100.0%) 22 (100.0%)   
 
Table 5. Frequency of the Number of Cores. 
Number of Cores Frequency Percent 
1-5 30 17.2 
6-10 129 74.1 
11-15 106 60.9 



 
 
 
 
 

 
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16-20 16 9.2 
Above 20 5 2.9 
Not Stated 47 27.0 
Total 174 100.0 

 

DISCUSSION 

This study revealed that prostate cancer accounted 
for 46.4% of all newly diagnosed prostate 
pathologies at our Centre. This is higher than a 
range of 22.4% to 37.4% reported from studies 
from other parts of Nigeria (Mohammed et al., 
2003, Okeke et al., 2017 and Obiorah et al., 2011). 
The higher incidence reported in our study may be 
due to the considerably higher sample size in our 
study as compared to the works done in Kano, 
Port Harcourt and a previous study in Lagos 
(Okeke et al., 2017, Obiorah et al., 2011 and Bah et 
al., 2001). The higher sample size at our Centre 
may also be partly due to the fact that the Lagos 
State Government has in the recent years 
embarked on free prostate cancer screening 
exercise for some elderly citizens which resulted in 
a high turn-out of subjects, some of whom were 
diagnosed with prostate cancer. Besides, Lagos is 
Nigeria’s commercial capital and the most 
populous City in the country. 

The median age of men diagnosed with prostate 
cancer in our series is 70 years, with the lowest age 
being 50 years, while the highest was 90 years. 
This finding is consistent with a WHO report which 
states that majority of cases of cancer of the 
prostate occur after the age of 50 years and its 
incidence peaks in the 70s (WHO, 2004). The 
WHO report further stated that worldwide, about 
three-quarters of all cases occur in men aged 65 
or more.   Studies from other parts of Africa show 
that the incidence of prostate cancer rises from the 
age of 50 years (Bah et al., 2001 and Babb et al., 

2014). Oluwole et al in Zaria, Nigeria, reported that 
prostate cancer was seen in two subjects aged 30 
and 32 years, with a peak age of diagnosis being 
the sixth decade and a mean of 64.5 years. 

Majority of the subjects in this study are of the 
Yoruba ethnic extraction, representing 74.2%. The 
reason for this observation is that the study was 
done in Lagos, which is located in the South-West 
of Nigeria, home to the Yoruba ethnic group. The 
remarkable proportion of non-Yoruba men in this 
study, representing 25.8%, gives credence to the 
fact that Lagos is a cosmopolitan city, where 
people of all ethnic nationalities, including foreign 
nationals in Nigeria live and work. 

Most of the cancer diagnoses in this study were 
made on trucut prostate biopsy specimens (94.9%) 
as against prostatectomy specimens which 
represent only 5.1%. This is similar to the report in 
a study done in Port Harcourt, Nigeria by (Obiorah 
et al., 2011) which also shows a much higher 
proportion of cancer diagnosis on trucut biopsy 
specimens (82.8%) compared to prostatectomy 
specimen (17.2%). On the other hand, a study in 
Zaria (Oluwole et al., 2015) revealed a much lower 
proportion of cancer diagnosis in trucut biopsies 
(57%) as compared to open prostatectomy (43%). 
Cases of carcinoma in prostatectomy specimen 
tend to be an incidental finding, as most 
prostatectomies are done on the grounds of an 
impression of benign prostate disease. This 
observation draws attention to the need for 
thorough histological examination of 



 
 
 
 
 

 
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RESEARCH 

prostatectomy specimens considering the 
possibility of finding a focus of cancer. 

An important highlight of the present study is the 
fact that majority of the prostate cancer were 
adenocarcinoma (97.8%). This is similar to the 
observation of authors of similar studies both 
locally and around the world (Haas et al., 2008, 
Oluwole et al., 2015, Obiorah et al., 2011, Odedina 
et al., Gueye et al 2003, Elen et al., 1991 and 
Anunobi et al., 2011). 

Our study shows that grade 5 prostate cancer is 
the most commonly diagnosed at our Centre 
(37.5%). This is followed by grade 3 disease, seen 
in 10.2% of cases. This is in contrast to the finding 
in Ibadan, Nigeria where it was observed that the 
commonest Gleason grade was 3 (Okolo et al., 
2008).  On the other hand, the study in Port 
Harcourt, south-south Nigeria, (Obiorah et al., 
2011)  shows that the majority of the cases in that 
series were of Gleason score of 8 (grade 4) which 
is similar to findings in Zaria (Oluwole et al., 2015)  

and another study in Lagos (Anunobi et al., 2011). 
However, a study in the United States shows that 
the commonest Gleason grade is 3 with an overall 
decline in scores from 8-10 to less than 6 in recent 
years (Gueye et al., 2003). A plausible explanation 
for the higher proportion of high grade cancers 
diagnosed at our Centre is that most of the 
patients present late to the hospital and already 
have advanced disease at diagnosis. The decline 
noted in the US study is as a result of improved 
early detection and diagnosis of prostate cancer in 
that country (Harget et al., 2016). Grade 1 tumour 
was most commonly observed in the 50-60 years 
age group (11, 28.2%). Conversely, high grade 
tumour (grade 5) was most frequently seen in the 
71-80 years group. It is pertinent to note that 

grade is not statistically dependent on age at 
diagnosis (P>0.05).   

Our study shows that the most frequent number 
of prostate biopsy cores sent to our laboratory is 
10 (11.2%), with some surgeons rarely sending as 
few as 2 cores and as many as 32. Or observation 
is consistent with the finding in an Asian study 
which revealed that 6 to 12 cores of prostate 
biopsy provide similar efficacy as more biopsy 
cores (Tanaka et al., 2015). These authors also 
opined that the number of cores to be taken 
should be determined by the prostate volume. 
They further suggested that increasing the number 
of cores increases the rate of cancer detection; 
however, the optimal number of prostate cores to 
obtain is still an open question.  

CONCLUSION 

This study shows that most of the prostate cancer 
diagnoses made in the Mayo Height Laboratory, 
Lagos State University Teaching Hospital were on 
trucut biopsy specimen. Prostate cancer is more 
commonly seen in men in the 7th decade of life 
(61-70 years) with a median age of 70 years. 
Majority of these patients already have high grade 
adenocarcinoma at diagnosis. This observation 
calls for the need for early detection so as to 
reduce mortality from the disease. Public 
awareness on prostate cancer will enable men to 
recognize early symptoms and seek medical help 
before the disease advances. The need for routine 
screening for early detection is also very crucial. 
This study also shows that surgeons frequently 
sent between 6 to 10 prostate biopsy cores to our 
Centre. This number is shown to be adequate for 
diagnosis. The observation that carcinoma was 
diagnosed in some prostatectomy specimen which 
were believed to be benign, draws attention to the 



 
 
 
 
 

 
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RESEARCH 

need for Pathologists to thoroughly examine 
prostatectomy tissues as foci of cancer may 
present. 

Acknowledgements 
The authors want to acknowledge the assistance 
rendered by the Management of Mayo Heights 
Laboratory in extracting relevant data from the 
laboratory information system. 

Conflict of interest 
The authors confirm that there is no conflict of 
interest and no funding was received for this work. 

Authors’ contributions 
Emiogun EF, was responsible for study 
conceptualization, design and literature search. 
Williams OO, performed literature search and data 
collation. Obafunwa JO was involved in study 
conceptualization, data analysis and editing of final 
draft. 

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