Country: Sri Lanka
Responding officers: Dr Gamini de Silva, BDS, FFDRCS, Consultant Oral and Maxillofacial
Surgeon, Chairman Commission on Oral Diseases.
Email: bgsdesilva@gmail.com
Dr A.A.Hemantha Amarasinghe, BDS, MSc, MD. Cancer Epidemiologist &
Consultant in Dental Public Health, Committee member Commission on Oral Diseases.
Email: hemanthaamarasinghe@yahoo.com
Oral cancer scenario in Sri Lanka
Incidence and trend
In Sri Lanka, higher incidence of cancers was reported in females (73.3 per 100,000 population)
compared to male patients (68.1 per 100,000 population). Cancers in the oral cavity, lungs,
oesophagus, colon & rectum and lymphoma are the five most common cancers among males in
2005. Cancers in the breast, cervix, ovary, thyroid, and oesophagus are the five most common
cancers among females in 2005 (Cancer incidence data: Sri Lanka Year 2001 -2005). Oral
cancer is the most common cancer among males and ranks sixth among women, reported to
account for 12% of total malignancies in the country (National Cancer Control Programme Sri
Lanka, 2009). The incidence of cancer of the oral cavity and oro-pharynx in Sri Lanka,
standardized to the world standard population, in the year 2005, was 14.1 and 3.8 per 100,000
in males and females respectively (National Cancer Control Programme Sri Lanka, 2009).
According to the National Cancer Registry, number of new cases of oral cancer reported in Sri
Lanka was shown to be static from year 2000 to 2005 but percentages of oral cancer from all
reported cancers was declining trend in this period (National Cancer Control Programme Sri
Lanka, 2009) (Table 1).
Table 1.1 Leading cancer sites in both sexes in Sri Lanka: 2003 - 2005
2003
Site
2004
2005
No.
Rank
%
No.
Rank
%
No.
Rank
%
1679
1
14.1
1785
1
14.1
1908
1
14.3
1398
2
11.8
1615
2
12.8
1617
2
12.1
Esophagus
983
3
8.2
1015
3
8.0
1022
3
7.6
Cervix uteri
749
5
6.3
816
4
6.5
881
4
6.6
Trachea,
762
4
6.4
795
5
6.3
832
5
6.2
Thyroid
561
7
4.7
705
6
5.6
752
6
5.7
Colon
558
9
4.7
664
7
5.3
741
7
5.6
Lymphoma
473
10
4.0
528
10
4.2
604
8
4.5
Ovary
560
8
4.7
627
8
5.0
596
9
4.4
Leukaemia
568
6
4.8
615
9
4.9
570
10
4.3
69.8
9165
72.5
9523
Breast
Lip,
oral
cavity
&
pharynx
bronchus
&
lungs
&rectum
Top 10
8291
71.2
According to the Sri Lankan National Oral Health Survey 2002/2003, it is estimated that more
than 284,000 people are alive with Oral potentially malignant disorder (OPMD); a prevalence of
3.4% (Ministry of Health Sri Lanka, 2009). In Sri Lanka, the prevalence of oral leukoplakia and of
OSF ( oral submucous fibrosis) is reported as 26.2 and 4.0 per 1000 respectively.(Ministry of
Health Sri Lanka, 2009) Studies in central Sri Lanka estimated the prevalence of all OPMD at
4.2% (Warnakulasuriya et al., 1984), that among tea estate workers at 6.7%.(Ariyawardana et
al., 2007)
According to the recent study conducted in the Sabaragamuwa provice, was reported
prevalence of OPMD as 11% in the rural and estate sector.
Risk factor
According to the study conducted by Dr Kasthuriratne in 2007, showed that betel chewing (OR:
1.94 CI 1.23-3.07) and alcohol drinking (OR: 4.65 CI 2.47- 8.71) were significant risk factors for
development of oral cancer (Kasthurirathne, 2007).
Study conducted in the Sabaragamuwa province of Sri Lanka (Amarasinghe et al., 2010b): betelquid chewing and alcohol consumption were significant risk factors for OPMD. Use of betel quid
shows a strong dose-response relation. The adjusted OR for daily-chewers was 10.6 (95% CI, 3.6
– 31.0) after controlling for all other variables. An increasing trend was shown for frequency
(quid per day) and duration (years). The adjusted OR was significant for chewing 3 or more
quids/day, increasing a further 4 fold with 4-5 quids/day (Table 2). A significant increase (2.5fold) of OR was observed for betel chewing more than 20 years compared to 10-20 years.
Moreover, the risk of betel-quid chewing with or without tobacco after adjusting shows an OR
of 5.5 (1.6-19.2) without tobacco and 14.9 (4.5-49.3) with tobacco, compared to the neverchewers. The habit of betel-quid chewing was further analysed for length of time a quid was
customarily kept in the mouth: adjusted OR for presence of an OPMD was 11.4 (3.9-33.3) for
those holding a quid for 1-10 minutes, rising to 25 (6.5-95.8), when chewing for 21-30 minutes.
Table 2 Betel-quid chewing habits and risk of OPMD
Characteristics
Cases
(n= 101)
Controls
Crude OR
Adjusteda OR
(±95%CI)
(±95%CI)
1.0
1.0
(n= 728)
n (%)
n (%)
4 (4.0)
277 (38.0)
Betel-quid chewing
Never
Past
2 (2.0)
36 (4.9)
3.8 (0.7-21..7)
2.4 (0.4-14.5)
Occasionally
3 (3.0)
83 (11.4)
2.5 (0.5-11.4)
2.0 (0.4-9.4)
92 (91.1)
332 (45.6)
19.2 (6.9-52.9)
10.6 (3.6-31.0)
No chewing
4 (4.2)
277 (45.5)
1.0
1.0
1-3
7 (7.3)
125 (20.5)
3.9 (1.1-13.5)
2.6 (0.6-11.4)
4-5
17 (17.7)
96 (15.8)
12.2 (4.0-37.3)
10.2 (2.8-37.0)
6-10
42 (43.8)
88 (14.4)
33.0 (11.5-94.7)
17.7 (5.1-61.3)
>10
26 (27.1)
23 (3.8)
78.3 (25.1-243.6)
75.5 (17.6-324.7)
4 (4.2)
277 (45.8)
1.0
1.0
≤ 18
31 (32.3)
67 (11.1)
32.0 (10.9-93.9)
15.2(4.2-54.2)
>18
61 (63.5)
261 (43.1)
16.2 (5.8-45.1)
9.4(3.0-29.4)
4 (4.2)
277 (45.9)
1.0
1.00
≤ 10 yr
15 (15.8)
87 (14.4)
11.9 (3.8-36.9)
8.1 (2.3-28.5)
>10 - ≤ 20 yr
17 (17.9)
70 (11.6)
16.8 (5.5-51.5)
8.2 (2.2-30.3)
> 20 yr
59 (62.1)
170 (28.1)
24.0 (8.6-67.3)
18.6 (4.9-69.6)
Daily
Frequency of chewing
(Quid per day)b
Age started chewing b
No chewing
Duration of
chewing(yr)b
No chewing
Type of betel
chewingb
No chewing
4 (4.3)
277 (45.8)
1.0
1.0
Without tobacco
13 (14.0)
134 (22.1)
6.7 (2.1-21.0)
5.5 (1.6-19.2)
With tobacco
76 (81.7)
194 (32.1)
27.1 (9.7-75.4)
14.9 (4.5-49.3)
a
OR adjusted for sex, age (continuous), education, occupation and BMI (continuous), β-
carotene containing total fruit & vegetable portions (continuous), status of smoking and alcohol
drinking
b
the sum does not add to the total because past and occasional chewers were excluded from
the analysis.
Regular alcohol drinking was associated with an increased risk for OPMD, the adjusted OR for
weekly-drinkers being 3.5 (1.6-8.0). However a dose-response relationship was not observed
for frequency of consumption of alcohol. “Kassippu” was associated with a five times higher risk
than “arrack” (Table 3).
Table 3 Alcohol drinking habits and risk of OPMD
Characteristics
Cases
(n= 101)
Controls
Crude OR
Adjusteda OR
(±95%CI)
(±95%CI)
(n= 728)
n (%)
n (%)
No drinking
39 (38.6)
551 (75.7)
1.0
1.0
Ever Drinking
62 (61.4)
177 (24.3)
4.9 (3.2-7.6)
2.1 (1.0-4.4)
Alcohol Drinking
Past
4 (4.0)
29 (4.0)
1.9 (0.6-5.8)
1.2 (0.3-4.4)
2-3 year
11 (10.9)
45 (6.2)
3.4 (1.6-7.2)
1.1 (0.4-2.9)
Monthly
12 (11.9)
40 (5.5)
4.2 (2.1-8.7)
2.0 (0.7-5.3)
Weekly
35 (34.7)
63 (8.7)
7.8 (4.6-13.3)
3.5 (1.6-8.0)
No drinking
39 (53,4)
551 (90.2)
1.0
1.0
1-10 units
23 (31.1)
22 (3.6)
14.8 (7.6-28.8)
7.1 (2.4-21.6)
11-20 units
3 (4.1)
16 (2.6)
2.6 (0.7-9.5)
0.3 (0.03-2.8)
>20
9 (12.2)
23 (3.8)
5.5 (2.4-12.7)
3.2 (0.80-12.7)
No drinking
39 (52.7)
551 (89.9)
1.0
1.0
≤ 18 years
5 (6.8)
12 (2.0)
5.9 (2.0-17.5)
2.6 (0.5-12.8)
>18 years
30 (40.5)
50 (8.2)
8.5 (4.8-14.8)
3.5 (1.3-9.4)
No drinking
39 (52.7)
551 (89.9)
1.0
1.0
1-10 years
3 (4.1)
11 (1.8)
3.8 (1.0-14.4)
0.8 (0.2-4.6)
11-20 years
15 (20.3)
14 (2.3)
15.1 (6.8-33.6)
11.9 (2.9-48.6)
>20
17 (23.0)
37 (6.0)
6.5 (3.3-12.5)
2.3 (0.8-7.1)
Units per weekb
Age started drinkingb
Duration of
drinking(yrs)b
Types of Alcohol
No drinking
39 (52.7)
551 (91.1)
1.0
1.0
Arrack only
14 (18.9)
19 (3.1)
10.4 (4.8-22.3)
3.3 (1.1-10.3)
Kassippu only
7 (9.5)
3 (0.5)
33.0 (8.2-132.5)
17.5 (2.8-110.2)
Two combinationsc
9( 12.2)
16 (2.6)
7.9 (3.3-19.1)
1.9 (0.4-7.7)
Three combinationsc
5 (6.8)
23 (3.8)
3.1 (1.1-8.5)
0.9 (0.2-4.3)
a
OR adjusted for sex, age(continuous), education, occupation and
BMI (continuous), β-
carotene containing total fruits & vegetable portion (continuous), status of smoking and betelquid chewing.
b
the sum does not add to the total because past and occasional drinkers were excluded from
the analysis.
c Combination
drinking habits were analyzed for arrack, kassippu, beer, toddy, wine and whisky
The logistic regression analysis demonstrated a synergistic effect between betel-quid chewing
and alcohol drinking. The risk of OPMD for chewers who also drank alcohol increased from 14.3
to 50.3 fold when compared to abstainers. Moreover, the risk of OPMD for alcohol drinkers
who also chewed betel, increased from 28.7(2.3-361.0) to 50.3(14.8-170.6) fold when
compared with abstainers. The crude OR for combined habits was 50.3(14.8-170.6): dropping
slightly when adjusted for socio-demographic factors to 31.9 (7.2-141.0). Attributable risks (AR)
and population attributable risks (PAR) for daily betel-quid chewing were 90.6% and 84%
respectively: for alcohol consumption 72% and 25% (Amarasinghe et al., 2010b).
According to the study in the estate sector in central Sri Lanka (Ariyawardana et al., 2007), the
subjects showing risk of OPMD, smoked (OR=2.2, 95% CI:1.7-2.7), alcohol drank(OR=1.4,95%CI,
1.2-1.7) and chewed betel (OR=3.0,95%CI, 2.2-4.0) Which were significantly higher than
abstainers. Adjusted odds ratios computed from a logistic regression model were
overestimated because it did not consider socio-demographic variables like age, sex,
occupation and diet which are statistically very important.
Ariyawardana & Vithanaarachchi (2006), conducted a case control study to evaluate the effects
of betel chewers, tobacco smoking and alcohol consumers on oral submucous fibrosis in Sri
Lanka. A total of 74 patients with OSMF and 74 controls who consecutively attended the oral
medicine clinic at the Dental Hospital (teaching) Faculty of Dental Sciences, University of
Peradeniya, Sri Lanka, were included in the study. Betel chewing was the only significantly
associated factor in the etiology of OSMF (OR = 171.83, 95% CI: 36.35 – 812.25) (Ariyawardana
et al., 2006).
Prevention programmes
A pioneer study conducted in Sri Lanka in the early 1980’s using Primary Health Care (PHC) staff
in detection of OPMD and oral cancer reported a sensitivity of 89% (Warnakulasuriya et al.,
1984). As a result, this approach has been included in the National Health Policy of Sri Lanka
since 1990 (Ministry of Health Sri Lanka, 1990). In spite of this, no sustainable screening
programmes have been implemented and Sri Lankan hospitals are reporting an increased
proportion of patients with oral cancer presenting with advanced, often incurable, disease. This
is most unfortunate in light of the evidence from the extensive Trivandrum Oral Cancer
Screening [TOCS] study which shows that deaths can be prevented in high risk communities by
such programmes (Sankaranarayanan et al., 2005).
We have determined that the main obstacles to effective oral cancer screening over the
intervening three decades include: the lack of adequate guidelines for PHC staff, particularly
concerning which individuals should be examined; an excessive workload, including their duties
with mothers and babies, and with immunisation programmes; devolution of all vertical
preventive programmes to the provincial level; and lack of quality continuing education and
assessment systems for health workers (Amarasinghe, 2007). As a possible solution to these
problems, we have developed a model designed to identify, in advance, individuals at high risk
for oral cancer and for OPMD who can then be targeted for oral examination and for focused
preventive measures (Amarasinghe et al., 2010a). Our approach is consonant with the Crete
Declaration on Oral Cancer Prevention (Peterson, 2005).
Public awareness
The level of awareness of oral cancer and OPMD among dental outpatients was assessed in a
hospital-based study in Sri Lanka; this revealed that 95% of the respondents were aware of the
possibility of the occurrence of cancer in the mouth but only 45% were aware of the possibility
of precursor lesions, while 80% were aware of a causal relationship between the habit of betelquid chewing and oral cancer (Ariyawardana and Vithanaarachchi, 2005). In spite of this, a
recent study in a rural population of Sri Lanka revealed that 47% of those questioned chewed
betel quid (which contains betel leaf, areca nut and lime) with tobacco, and 15.7% betel quid
without tobacco (Amarasinghe, 2008).
Public awareness of oral cancer, OPMD and risk factors were assessed in the study conducted in
the Sabaragamuwa province of Sri Lanka in the year 2007-2008 which revealed that Of the
study subjects, 84% were aware of oral cancer but only 22.7% were aware of OPMD, when
weighted for over sampling of the estate sector (Amarasinghe et al., 2010c). Seventy percent of
the subjects were not aware of the three main symptoms of oral cancer and OPMD (white
patch, red patch, and persistent ulcer). Thirty two percent of the study subjects were not aware
that the chewing of betel quid is a high risk behaviour for oral cancer and OPMD. Questions
were also asked about the risks associated with the components of betel quid . Forty six
percent were not aware of the carcinogenic potential of tobacco in betel quid. Though the
knowledge on betel-quid chewing as a risk behaviour was known to two-thirds; an important
finding was that the danger of chewing areca nut in any form were not recognized by 75.8%
subjects. Almost two thirds (64.8%) were not aware of smoking risks and 81.4% were not aware
of the risks associated with the heavy consumption of alcohol. This study also investigated the
awareness of micronutrient deficiencies and poor oral hygiene as risk factors for oral cancer
and OPMD. Almost all (97.7%) were not aware of the implications of micronutrient deficiency
and 88.6% were not aware of the risks associated with poor oral hygiene (Table 4).
Table 4: Awareness of symptoms and risk factors of oral cancer and OPMD
Awareness
% not awarea
% Awarea
Oral cancer
Both oral cancer
only
and OPMD
70.4
20.1
9.4
Betel-quid chewing
31.8
57.8
10.2
Smoking
64.8
28.8
6.2
Alcohol
81.4
14.7
3.8
Awareness of Symptoms
Awareness of risk factors
Micronutrient deficiency
97.7
1.2
0.2
Poor oral hygiene
88.6
9.0
2.3
Awareness of oral cancer potential by ingredients in the betel quid
Betel leaves
82.4
15.6
2.0
Tobacco (added)
46.1
47.8
6.1
Areca nut
75.8
20.3
3.9
Lime
61.8
33.3
4.8
All above ingredients
91.3
7.9
0.8
a
Weighted for over-sampling of the estate sector
The majority of smokers, betel-quid chewers and alcohol consumers were not aware of the risk
of oral cancer/OPMD associated with the habit(s) they were practicing. “Ever” betel chewers
were 2.8 times more likely not to be aware of the risk of oral cancer/OPMD conferred by the
habit of betel-quid chewing compared to ‘never’ chewers. Subjects consuming alcohol were 1.9
times more likely not to be aware of the risk of the habit they practiced compared to nonconsumers.
In relation to the awareness of the magnitude, fatality and measures of prevention of oral
cancer, only 22.9% were aware that oral cancer was more common in Sri Lanka than lung
cancer. Moreover, 63.9% agreed that oral cancer is often fatal and 54.8% agreed that early
detection could save lives.
People who were aware of oral cancer and OPMD were further questioned about their sources
of information. Overall, mass media, family members and friends were the main sources of
information. Only 14.5% acquired relevant knowledge from health personnel. The majority of
subjects in villages derived knowledge about cancer through the mass media, predominantly
TV/Radio (41.2%) and newspapers (21.8%). However in the estate sector the main source of
information was through family members and friends (44.2%), and the mass media accounting
for 31% (Table 5).
Table 5: Sources of information about oral cancer and OPMD according to the area of residence
Sources
Village (%)
Estate (%)
Total (%)
Health personnel
14.1
16.3
14.5
Newspapers
21.8
13.2
20.2
TV/Radio
41.2
17.8
36.9
Family members/friends
15.1
44.2
20.5
Other
7.7
8.5
7.9
Future activities
National Cancer Control Programme has developed 10 year plan to reduce the burden of oral
cancer by 15% by the year 2020. The following key activities are included in the 10 year plan.
1.
2.
3.
4.
Development of guidelines for management of oral cancer and OPMD.
Establishment of an island wide surveillance system for oral cancer and OPMD.
Utilization of risk factor model for early detection of oral cancer
Strengthening the ongoing early detection programmes
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