Introduction
Cancer is defined as the abnormal division of cells beyond
control, resulting in the invasion of nearby and
distant tissues.[] Globally, it is a leading cause of death
after cardiovascular diseases, responsible for 10 million
deaths in 2020.[] The International Agency for Research
on Cancer (IARC) estimates that globally 1 in 5
people develop cancer during their lifetime.[]
According to IARC, in 2020, there were 19,292,789
new cases worldwide, and 9,958,133 of them died of
cancer.[] Breast cancer is the most frequent cancer
(11.7%), followed by lung (11.4%), colorectal (10.0%),
prostate (7.3%), and stomach (5.6%) in both genders
worldwide.[]
Bahrain is a 717.5 km² archipelago of 33 islands off
the western shores of the Arabian Gulf. With an estimated
population of 1.7 million people, it was reported
as the third most densely populated country in the
world in 2020.[] Overall, the population of Bahrain
comprises 52.6% expatriates and 47.4% local citizens.
In 1994, a Ministerial Decree mandated the notification
of all cancer cases to the Bahrain Cancer Registry
(BCR) at the Ministry of Health.[] In 2007, a cancer
statistic based on 2,405 cases from 1998 to 2002 was
published.[] In this publication, the age-standardized
incidence rates (ASR) were 162.3 and 145.2 per 100,000
for Bahraini males and females, respectively. Generally,
Bahraini men had a higher ASR for most cancer
types, and the most common type of cancer in males
was lung (35.2 per 100,000), followed by bladder (14.5
per 100,000) and prostate (14.3 per 100,000) while in
females it was breast (46.8 per 100,000), followed by
lung (12.2 per 100,000) and ovarian (7.7 per 100,000).
[] Furthermore, the Gulf Center for Cancer Control
and Prevention published a report in 2011, where Bahrain
was reported to be one of the three countries with
the highest incidence in the Gulf.[]
Earlier, cancer treatment was mainly carried out in
the King Hamad University Hospital and Salmaniya
Medical Complex. In February 2019, the 206-bed Bahrain
Oncology Center (BOC) was inaugurated to provide
comprehensive services in the domains of oncology,
hematology, pediatric oncology, and hematopoietic
stem cell transplantation. With the establishment of the
Center, the standard of care and treatment modalities
was significantly upgraded. Furthermore, the National
Tumor Board (NTB) was started several years before
the inauguration of the center, which became a national
platform for healthcare professionals to discuss cancer
cases diagnosed in the whole country and conduct indepth case discussions, fulfilling its aim. The cases documented
carefully within the National Tumor Board platform,
now in a web-based system, from 2016 onwards
are from all over the islands, presented from both public
and private healthcare facilities. The cases discussed
through the NTB represent the majority of the solid
cancer cases in Bahrain and can be used as a database to
conduct further research in the epidemiology of specific
cancers in the future. This will ultimately provide evidence
to quantify types of prevalent cancers, guide future
research, cancer treatment, and resource allocation.
Our aim is to analyze cancer cases presented in
the National Tumor Board in the Kingdom of Bahrain
from 2016 to 2020.
Methods
All the cancer cases submitted to the NTB Office from
both private and public hospitals in Bahrain between
1 February 2016 and 29 February 2020 were collected
and stored in a Microsoft Excel spreadsheet. This
spreadsheet was then further upgraded to include key
demographic, epidemiologic, and clinical parameters.
Before starting the study, approvals from the Bahrain
Oncology Center and King Hamad University Hospital
Research and Ethics Committee (Approval number 20-
354) were obtained. The collected data was reviewed by
the researchers to ensure accuracy. Patients with hematological
cancers were excluded from the final analysis,
and only solid tumor cases were included. The patient
charts with insufficient, deficient, or unreliable information
were excluded. Staging was recorded in line
with the American Joint Committee on Cancer (AJCC)
TNM Staging Edition 8 wherever applicable. Missing
data was labeled as unknown.
The Excel data analyzed was transferred to and analyzed
using the Statistical Package for the Social Sciences
(SPSS) software v28. Most of the data were presented
as frequencies and ratios. Ratios were expressed
as percentages (%).
Results
Our data collection included 2,336 patients between
February 2016 and February 2020. Out of these 2,336
patients, 2,061 were histopathologically proven malignant
cases at presentation, 48 were benign cases, and
227 were suspicious of malignancy at presentation.
Therefore, the results and discussion will be based on
the data obtained from the 2,061 cases.
Of the 2,061 malignant cases discussed in the
4-year period, 122 were presented between February
and December 2016, 109 in 2017, 630 in 2018, 988 in
2019, and 212 cases were presented in January and February
2020. Although we were not able to analyze the
whole year 2020 cases, we added the total number of
new cases discussed in the year 2020 to give a sense of
the trend, exceptionally in Figure 1.
Fig. 1: Distribution of cancer diagnosis over the years.
Note: Year 2020 cases were added only graphic
puroses but not analyzed in database.
The median age of all the patients was 56 years
(range: 2?95). There were 1,367 females (66.4%) and
694 males (33.6%) as shown in Figure 2.
Fig. 2: Distribution of cancer in both sexes.
In 1,989 cases, nationality was recorded. Of these,
1,768 (88.9%) were Bahraini and the remaining 221
(11.1%) were of other nationalities. Therefore, our
data is more representative of Bahraini patients,
rather than expatriates.
Of the 2,061 malignant cases, 2,024 (98.2%) were
solid tumor malignancies. 129 cases were diagnosed
prior to 2016, 142 cases in 2016, 200 cases in 2017, 481
cases in 2018, 792 cases in 2019, 81 cases between January
and February 2020, and 199 cases did not have a
documented date of diagnosis on file (Fig. 3).
Fig. 3: Distribution of cancer diagnosis over the years.
Among the 2,024 solid tumor cases, the top 5
cancers were breast cancer (37.1%), colorectal cancer
(11.8%), thyroid cancer (6.5%), prostate cancer
(5.9%), and head & neck cancers (4.8%) in the whole
patient population (Fig. 4). The frequencies of cancer
per gender were variable. In 693 males, the top 5 cancers
were colorectal (19.2%), prostate (17.3%), head
& neck (10.1%), bladder (7.2%), and lung (6.6%). In
1,368 females, the top 5 cancers were breast (55.2%),
colorectal (8.0%), thyroid (7.2%), uterine (6.7%), and
ovarian (3.2%) as shown in Figure 4.
Fig. 4: Cancers in the whole population (a), in females (b) and in males (c) with decreasing
frequencies including hematological cancers.
It was possible to determine the stage of disease
in 1,173 solid tumor cases. 44 cases (3.8%) were stage
0, 198 cases (16.9%) were stage I, 347 cases (29.6%) were stage II, 299 cases (25.5%) were stage III, and
285 cases (24.1%) were stage IV (Fig. 5).
Of the 2,061 malignant cases including hematological
cancers, 41 (2.0%) cases had multiple primaries.
In 1,078 patients, family history was recorded, among
which 409 (19.8%) had a positive family history of cancer
(Table 1).
Fig. 5: Distribution of cancer by stages at diagnosis,
N=1173.
Table 1: Key parameters of patients analyzed
Discussion
After the establishment of the National Tumor Board
in the Kingdom of Bahrain, this is the first publication reporting specific patient demographics, types of cancers,
their relative frequencies, and stage distribution.
We studied 2,061 cases discussed in the National Tumor
Board over a 4-year period. The median age was 56 years, and 66.4% were females. The top 5 cancers were breast
(37.1%), colorectal (11.8%), thyroid (6.5%), prostate
(5.9%), and head & neck (4.8%) in both genders. In males,
the top 5 were colorectal (19.2%), prostate (17.3%), head & neck cancers (10.1%), bladder (7.2%), and lung (6.6%);
whereas in females, they were breast (55.2%), colorectal
(8.0%), thyroid (7.2%), uterine (6.7%), and ovarian
(3.2%). Around 50% were in advanced stages of III or
IV. The number of new cases in 2019 was almost 1,000,
and it was 1,378 in the year 2020 (personal communication
with NTB). Although our data does not come from
a cancer registry, it provides valuable information on statistics,
since the majority of cases diagnosed in Bahrain
are discussed in the National Tumor Board where the
data are recorded in a structured fashion.
According to the International Agency for Research
on Cancer (IARC) in 2020,[,] breast cancer
was the most frequent cancer (11.7%) followed by lung
(11.4%), colorectal (10.0%), prostate (7.3%), and stomach
cancer (5.6%) in both sexes.[,] In males, the most
frequent cancer is lung cancer (14.3%), followed by
prostate (14.1%), colorectal (10.6%), stomach (7.1%),
and liver cancers (6.3%). In females, the most frequent
cancer is breast cancer (24.5%), followed by colorectal
(9.4%), lung (8.4%), cervical (6.5%), and thyroid cancer
(4.9%).[,] In Bahrain in 2020, according to the IARC
fact sheet, there were 1,215 new cases in a population
of 1,701,583.[] The data was taken from the Bahrain
National Cancer Registry. In both genders, the top 5
cancers were breast (20.0%), colorectal (12.1%), lung
(7.9%), non-Hodgkin's lymphoma (5.8%), and leukemia
(4.6%).[] In males, they were colorectal (14.5%),
lung (11.4%), prostate (8.9%), non-Hodgkin lymphoma
(7.9%), and bladder (7.7%). In females, they were
breast cancer (37.9%), colorectal (10%), ovary (5.9%),
uterine (5.5%), and lung (4.8%).[]
In one study published from Bahrain, where 2,405
cases were analyzed from 1998 to 2002,[] the annual
average number of cases was 481, and the age-standardized
incidence rates (ASR) for Bahraini males and
females were 162.3 and 145.2 per 100,000, respectively.
The most common type of cancer was lung for males
(35.2 per 100,000), followed by bladder (14.5) and
prostate (14.3), and breast for females (46.8), followed
by lung (12.2) and ovarian (7.7). In another report on
GCC (Gulf Cooperation Council) Countries,[] where
4,212 cases were reported from 1998 to 2007 from
Bahrain, the ASR was 158.5 per 100,000 for both males
and females, much higher than the reported 79.3 for
all GCC countries. In this report, the top five cancers
in males were lung (17.8%), colorectal (8.8%), prostate
(8.2%), bladder (7.9%), and leukemia (6.3%), and in
females; breast (37%), colorectal (6.1%), lung (5.7%),
thyroid (5.7%), and ovarian (4.8%).
The previously reported annual number of cases
in Bahrain was around 500,[,] but in our data, the
discussed number of cases per year was almost 1,000
in 2019 and 1,378 in 2020 (personal communication
with NTB) as shown in Figure 1. Although our data
is not epidemiological, it comes from a national body
where the majority of cases are discussed. In Figure 1,
we see that the number of cases increases over time,
which is a reflection of the increasing percentage of
cases discussed in NTB. We assume that the contribution
coming from a true increase must be much
less, but it is from the fact that more of the newly diagnosed
cases have been discussed in NTB over the
years. We believe that our data is a better representation of the current situation. It strongly suggests that
the incidence rate is higher than previous estimations.
The possible reasons could be under-reporting during
the previous studies, different reporting methods, and
a possible increase in cancer incidence. Many Bahraini
patients were treated abroad previously, while
nowadays fewer patients are opting for treatment
abroad after the establishment of the Bahrain Oncology
Center. It was possible that those patients getting
diagnoses and treatment abroad were not captured in
the Bahrain Cancer Registry and GCC report.
In our data, the GCC report, and the Bahrain cancer
registry, the percentage of breast cancer was much
higher than the rest of the world, reaching up to 37.9-
55% in females, compared to 24.5% in the rest of the
world. Another interesting finding in our data is that
thyroid cancer is the 3rd most frequent cancer in both
genders, whereas it is not in the top 5 list in the world
and IARC data in Bahrain. Uterine cancer was the 5th
most frequent cancer in females in our data.
In Bahrain, lung cancer was one of the least frequent
cancers in our data, which does not match
with previous publications,[,] compared to the
world where it is the 2nd most common in the whole
population and the most common in males. This is
noteworthy and perhaps requires further attention
and explanation.
The difference from the rest of the world is difficult
to explain. One important factor to consider
could be the differing methodologies, as our data is
not from a registry. However, it is expected to match
a registry, since the majority of cases are discussed
in the National Tumor Board, and we believe that we
cover 70?95% of cases diagnosed. Looking at Saudi
Arabia, which is very close to Bahrain and culturally
similar, lung cancer (12.2%) is the most common,
followed by breast (11.4%), colorectal (10.2%), stomach
(6.6%), and prostate (6.2%) in the whole population,
whereas in females, breast cancer was the most
common with a frequency of 24%, and in males, the
most common cancer was lung cancer (15.4%).[]
In Qatar, the pattern was similar to Saudi Arabia.[]
One explanation might be the population structure.
Although 52.6% of 1.64 million people are expatriates,
only 14% of cases discussed were of other nationalities
in our data, while 85.8% of the cases discussed
were Bahraini nationals, which accounts for
1,768 cases out of a population of 777,360 (0.23%).
This likely reflects the fact that expatriates tend to return
to their home countries to receive a diagnosis or
start treatment for several reasons, including but not limited to, avoiding the cost of treatment in Bahrain,
being near family and loved ones, etc. Likewise, IARC
uses the whole population of Bahrain while making
estimations, which might not reflect what is happening
in Bahrain. Furthermore, Bahrain is a country of
islands, naturally restricting population movements.
This might have created the difference through the
accumulation of certain genetic factors. Marriage
among relatives is a common practice as well. Factors
like obesity, sedentary lifestyle, diet patterns, smoking
patterns, or differences in data capture methods
might explain the difference. As per the Global Obesity
Observatory, obesity among women is 42% and
the category of overweight is around 70% in Bahrain,[] while smoking seems to be less prevalent in
Bahrain (28% in males, 6% in females) compared to
the average in the world (36.7% of all men and 7.8%
of the world's women).[]
We also analyzed the stage at presentation. It was
available in 63% of the cases. Of the patients staged,
25.5% were at stage III, and 24.1% at stage IV (Fig. 5),
indicating that 50% of the patients were diagnosed at
an advanced stage, in contrast to the United States of
America, where most patients are diagnosed at early
stages.[] This could be explained by many factors,
from cultural to religious to healthcare system. Whatever
the reason, it highlights the need for a nationwide
intervention, from education to awareness and
to screening programs.
Similarly, only 20% of the cases had a recorded family
history, despite the strong prevalence of cancer on
the island.
Conclusion
In this study, the number of cases, more than 2,000, is
high enough to draw conclusions. It covers the great
majority of cases diagnosed in Bahrain. Therefore, its
results help us understand some fundamental parameters
pertaining to cancer in Bahrain. It reveals some
unique features. However, it must be kept in mind that
this is not a formal registry.
In conclusion, our study shows that the National
Tumor Board is becoming increasingly pivotal. The
frequency distribution of cancer may differ from the
rest of the world, with a much higher number of cases
of breast and thyroid cancers, and fewer lung cancers.
The cases are presenting at late stages. We believe that
there is a need to focus on prevention and early detection
of cancer in Bahrain.
Acknowledgment: The authors would like to acknowledge
the commendable efforts of Dr. Yusuf Alawadhi.
Peer-review: Externally peer-reviewed.
Conflict of Interest: All authors declared no conflict of interest.
Ethics Committee Approval: The study was approved by
the Bahrain Oncology Center and King Hamad University
Hospital Institutional Review Board (no: 20-354, date:
21/07/2020).
Financial Support: None declared.
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