incidence and mortality rate of colorectal cancer in malaysia

INCIDENCE AND MORTALITY RATE OF COLORECTAL CANCER IN MALAYSIA
AUTHORS:
1) Given name: Muhammad Radzi
Family Name: Abu Hassan
Affiliation: Gastroenterologist, Medical Department, Sultanah Bahiyah Hospital
2) Given name: Ibtisam
Family Name: Ismail
Affiliation: Research Officer, Clinical Research Centre, Sultanah Bahiyah Hospital
3) Given name: Mohd Azri
Family name: Mohd Suan
Affiliation: Medical Officer,Clinical Research Centre, Sultanah Bahiyah Hospital
4) Given name:Faizah
Family name:Ahmad
Affiliation: Research Officer, Clinical Research Centre, Sultanah Bahiyah Hospital
5) Given Name: Wan Khamizar
Family name: Wan Khazim
Affiliation: Colorectal Surgeon, Surgical Department, Sultanah Bahiyah Hospital
6) Given name: Zabedah
Family name: Othman
Affiliation: Oncologist, Department of Radiotherapy and Oncology,Hospital Kuala Lumpur,
7) Given name: Rosaida
Family name: Mat Said
Affiliation: Gastroenterologist, Medical Department, Hospital Ampang
8) Given name: Wei Leong
Family name: Tan
Affiliation: Medical Officer, Clinical Research Centre, Sultanah Bahiyah Hospital
9) Given name: Siti Rahmah@Noor Syahireen
Family name: Mohammed
Affiliation: Pharmacist, Clinical Research Centre, Sultanah Bahiyah Hospital
10) Given name: Shahrul Aiman
Family name: Soelar
Affiliation: Research Officer, Clinical Research Centre, Sultanah Bahiyah Hospital
11) Given Name:Nik Raihan
Family name:Nik Mustapha
Address: Pathologist, Pathology Department, Sultanah Bahiyah Hospital
Funding sources: Nil
Corresponding author:
Given name: Muhammad Radzi
Family Name: Abu Hassan
Address: Clinical Research Centre, Sultanah Bahiyah Hospital, KM 6,Jalan Langgar, 05460 Alor
Setar, Kedah, Malaysia
Phone number: +604-7406227
Fax number: +604-7407373
Email: [email protected]
ABSTRACT
Objective:This is the first study in Malaysia that estimates the incidence and mortality rate for
colorectal cancer(CRC) patients by gender and ethnicities.
Method:Utilising National Cancer Patient Registry-Colorectal Cancer (NCPR-CC) data where 4501
patients were selected, patients’ survival status was cross-checked with the National Registration
Department. The analyses were performed with IBM SPSS Statistics. Age standardised rate(ASR) is
the proportion of colorectal cancer cases(incidence) and death(mortality) from 2008-2013, weighted
by the age structure of the population from the Department of Statistics Malaysia and using WHO
world standard population distribution.
Result:Overall incidence rate for CRC was 21.3 cases per 100 000 population. CRC was highest
among Chinese(27.4), as compared to Malay(18.95) and Indian(17.55).The ASR incidence rate of
CRC was 1.33 times higher among male than female (24.16 and 18.14 cases per
100,000,respectively). 2011(44.7%) deaths were recorded. The overall ASR for mortality was 9.8
cases among Chinese (11.85), followed by Malay (9.56) and Indian (7.08). The ASR for mortality was
about 1.42 times higher among male(11.46) compared to female(8.05)
Conclusion: CRC incidence and mortality is higher in male compared to female. Chinese ethnicity has
the highest incidence of CRC followed by Malay and Indian. The same trend was observed for the
mortality ASR rate.
Keywords: Colorectal Cancer, Incidence, Mortality, Ethnicity, Gender, Malaysia
INTRODUCTION
Colorectal cancer (CRC) has become the third most common cancer globally [1] and it has
been considered as one of the leading causes of death particularly in Western countries [2]. In 2014,
it was reported that 136 830 individuals were projected to be newly diagnosed colorectal cancer
patients with 50 310 mortality projection in United States alone [3]. Asian countries are not excluded
from the rise in CRC for the past 20 years [4] and the disease has also become a major health
concern. In Malaysia, CRC was found to be the second most common cancer, based on National
Cancer Registry Report 2007 [5].
Several studies had been conducted in Asian countries such as Japan, Hong Kong and
Singapore to investigate the incidence of CRC. In a study done by Tamara et al, it has been reported
that there was an increase in incidence among Japanese particularly in male compared to female in
all of its cohorts [6]. Similarly, an increase in incidence of CRC was observed from 1983 until 2006 in
Hong Kong [7]. Different ethnicity background has also been postulated to influence the risk of CRC.
Mateka et al studied the trend in incidence and mortality rates of CRC in the USA found that that it
was higher among Black American (66.9 per 10000 population) compared to White American, Asian,
Hispanic and Indian [8].
Located at the heart of South East Asia, Malaysia is a country with diverging ethnic groups
and cultural system. With more than 26 million population [9], Malaysia is a unique country which
comprised of three major ethnicities i.e Malay, Chinese and Indian that become our focus in this
study. To our knowledge, this is the first study in Malaysia that estimates the incidence and mortality
rate for CRC patients by gender and ethnicities.
METHODOLOGY
This study utilised secondary data from the National Cancer Patient Registry-Colorectal Cancer
(NCPR-CC). NCPR-CC is a national clinical database which aims to systematically collect data on
important aspects of colorectal cancer relevant to its prevention and treatment to enable healthcare
planning, implementation and evaluation in a defined population in Malaysia. Source Data Providers
(SDP) represent different regions of Malaysia i.e. the peninsular (north, central, south and east
coast), as well as, east Malaysia (Sabah and Sarawak). In our study, there were 34 participating
centres with at least one representative hospital from each 14 states of Malaysia. These SDP
comprised mainly of major referral public hospitals treating colorectal cancer. Clinical Research
Centre, Hospital Sultanah Bahiyah is the coordinating centre that manages the registry. All colorectal
cancer cases diagnosed from January 2008 until December 2013 were included.
All data are stored in a secure database with restricted access to authorised persons only. For the
purpose of this study, database of the registry was locked on 30 April 2014. This study utilised data
from 34 participating centres that were entered until 30 April 2014. Initially, 7287 data were
captured. Following data cleaning (namely exclusion of duplicated entry, anal cancers and metastatic
lesions to the colorectum), a total of 4501 patients were identified and included in this study.
Patients’ survival status was confirmed through checking their medical records, as well as, with the
National Registration Department, Ministry of Home Affairs. This study was registered with National
Medical Research Registry and approved by Medical Research Ethical Committee (NMRR-07-49-242).
Data analyses were performed using IBM SPSS Statistics for Window software version 20.0 [10].
Descriptive statistics were utilized to present the frequency and percentage for age groups, gender,
ethnicity, primary cancer site and patient status. Cross tabulation was used to get the number of age
category among gender and ethnic by patient status. Results of cross tabulation were copied and
pasted into Microsoft Excels 2007 to calculate the age standardised rate (ASR). Age standardised
rate (ASR) was needed to compare the cancer incidence and mortality with adjusted age-specific
between the different gender and ethnic in Malaysia, as well as, international comparisons. Age
standardised rate (ASR) is defined as the rate of colorectal cancer cases (incidence) and death
(mortality) per 100,000 population with a standard age structure. Age standardised rate (ASR) was
calculated by the direct approach given by the following equation:
𝑛
ASR =∑ 𝑟𝑖 (∑ 𝑛𝑖𝑠 )
𝑖𝑠
where 𝑟𝑖 is the weight from the WHO world standard population in the ith age class [11] and 𝑛𝑖𝑠 is
the weight from the ith age class of the population from the Department of Statistics (DOS) [9],
Malaysia.
RESULTS
There were 4501 cases of colorectal cancer reported in the National Cancer Patient RegistryColorectal Cancer (NCPR-CC) within the period of 2008-2013. Table I showed that out of 4501, 55.9%
were male and 42.9% were female (Table I). In term of ethnicity, Malay ethnic was the majority
(42.7%) followed by Chinese (40.3) and Indian (5.8%).
Table II shows that the age standardised incidence rate of colorectal cancer per 100,000 populations
was highest among Chinese (27.4) as compared to Malay and Indian (18.95 and 17.55 cases per 100
000 respectively). In addition, the age standardised incidence rate of colorectal cancer was about
1.33 times higher among male than female (24.16 and 18.14 cases per 100,000 respectively. There
were 2011 (44.7%) deaths recorded out of 4501 colorectal cancer patients during the six years
period (Table I). The mortality rate per 100,000 population was also highest among Chinese (11.85),
followed by Malay (9.56) and Indian (7.08). The age standardised mortality rate of colorectal cancer
was about 1.42 times higher among male compared to female (11.46 and 8.05 cases per 100,000
respectively).
DISCUSSION
As a multiethnic country, it is of our interest to study the incidence and mortality rate of CRC in
Malaysian population particularly amongst the three main ethnicities i.e Malays, Chinese, and
Indians. The result showed that the overall age standardised incidence rate for colorectal cancer in
Malaysia was highest amongst Chinese (27.35 per 100 000 populations), followed by Malay and
Indian (18.95 and 17.55 per 100 000 populations, respectively). Similar finding was reported from
population-based Singapore cancer registry report (2008-2012). In their report, age standardised
incidence rate for CRC Chinese ethnicity was 35.1 per 100 000 population, as compared to Malay
and Indian ( 24.6 and 17.1 per 100 000 population, respectively) [12].
Our study also compared the incidence of CRC between male and female. The age standardised
incidence of CRC is 1.33 times higher in male than female (24.2 and 18.1 cases per 100,000
respectively). Despite of geographical variation, similar finding was observed worldwide. Incidence
rate was found to vary ten-fold in male and female where the highest estimated rate of CRC being in
Australia/New Zealand with 44.8 and 32.2 per 100 000 populations in male and female, respectively.
The same scenario was observed in Western Africa with male (4.5 per 100 000 population)
compared to female with ( 3.8 per 100 000 population) [1].
There were 2011 (44.7%) deaths out of 4501 colorectal cancer patients recorded during the six-year
period. The mortality rate per 100,000 population, it mirrors the trend in CRC incidence, in which
Chinese ethnicity had the highest mortality (11.9), followed by Malay (9.6) and Indian (7.1).
Meanwhile, age standardised mortality rate in male was 1.42 times higher than female (11.46 and
8.05 per 100 000, respectively). A study by Jemal et al on global cancer statistics showed that
developed nations had age standardised mortality rate of 15.1 per 100,000. As for South East Asia,
age standardised mortality rate was 15.2 per 100,000 for male and 12.9 per 100,000 for female [13].
Based on the report from GLOBOCAN project, it was demonstrated that in the South East Asia
Region, the overall incidence of CRC in Malaysia was the third highest (18.3 per 100 000 population)
when compared with other country particularly its neighbouring country such as Singapore (33.7 per
100 000 population), Brunei (250.0 per 100 000 population), Phillipines (13.1 per 100 000
population), Indonesia (12.8 per 100 000 population) and Thailand (12.4 per 100 000 population). As
for the mortality rate, Brunei exhibited the highest mortality rate (12.0 per 100 000 population)
followed by Singapore, Malaysia, Indonesia, Philipines and Thailand (11.8,9.4,8.6,7.8, and 7.3 per
100 000 population, respectively) [1].
According to Parkin (2009), it is important for a registry database to review their data completeness
index where only a high degree of completeness will ensure the incidence and survival rate are close
to their true value [14, 15]. It was suggested that one of the possible ways to report the overall data
completeness of the registry is by calculating the mortality per incidence (M: I) ratio. In our dataset,
we demonstrated the index of completeness by assessing the M:I ratio, where we compared the
number of deaths, which were obtained from National Registration Department, Ministry of Home
Affairs, a source independent of the registry against the number of cases reported for the period of
time (2008-2013).
To our knowledge, this study is the most representative data reported so far which investigated the
incidence and mortality of CRC in different ethnicities in Malaysia, comparing between males and
females. In our study, out of 34 centres that contributed to the data, there was at least one
representative hospital from each 14 states of Malaysia where most of the centres are the major
referral public hospitals treating colorectal cancer.
In conclusion, we have demonstrated that the overall incidence of CRC in Malaysia was 21.3 cases
per 100 000 population where it was highest amongst Chinese ethnicity compared to Malay and
Indian. Similarly, Chinese ethnicity showed the highest mortality rate compared to other ethnicity.
Incidence and mortality rate were both higher in males as compared to females. These findings
illustrate the overall incidence and mortality rate of CRC in Malaysia as well as highlighting the
differences between different ethnicity and gender. It is our hope that these findings will help the
policy maker to strategies and improve CRC disease control plan in Malaysia.
ACKNOWLEDGEMENTS
The authors would like thank Director General of Health Malaysia for permission to publish this
paper. The authors would also like to thank all participating centres that contribute to the successful
of this registry.
CONFLICT OF INTEREST
The authors have no conflicts of interest to declare for this study.
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Table I. Descriptive statistics of colorectal cancer cases in National Cancer Patient Registry-Colorectal
Cancer, Malaysia, 2008-2013
Variables
Age Groups
<19years
20-24years
25-29years
30-34years
35-39years
40-44years
45-49years
50-54years
55-59years
60-64years
65-69years
70-74years
>75years
Not reported
Gender
Male
Female
Not reported
Ethnic
Malay
Chinese
Indian
Others
Not reported
Primary Cancer Site
Left sided
Right sided
Not reported
Patient Status
Alive
Dead
n (%)
11
17
47
65
112
194
328
465
627
713
650
616
613
43
(0.2)
(0.4)
(1.0)
(1.4)
(2.5)
(4.3)
(7.3)
(10.3)
(13.9)
(15.8)
(14.4)
(13.7)
(13.6)
(1.0)
2518 (55.9)
1933 (42.9)
50 (1.1)
1922
1814
259
484
22
(42.7)
(40.3)
(5.8)
(10.8)
(0.5)
3480 (77.3)
770 (17.1)
251 (5.6)
2490 (55.3)
2011 (44.7)
Table II. The incidence and mortality of patients in the NCPR-Colorectal Cancer, 2008-2013
Incidence
Mortality
Characteristics
Overall
Male
Female
Overall
Male
Overall
Ethnic
Malay
Chinese
Indian
Mortality/Incidence Ratio
Female
Overall
Male
Female
21.32
24.16
18.14
9.79
11.46
8.05
0.46
0.47
0.44
18.95
27.35
17.55
21.79
30.77
21.43
16.09
23.22
13.71
9.56
11.85
7.08
11.56
13.47
9.63
7.57
10.07
4.78
0.50
0.43
0.40
0.53
0.44
0.45
0.47
0.43
0.35