Country: Sri Lanka Responding officers: Dr Gamini de Silva, bds, ffdrcs



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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).

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): betel-quid 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 (2.5-fold) 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 never-chewers. 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)

n (%)

Controls

(n= 728)

n (%)

Crude OR

(±95%CI)

Adjusteda OR (±95%CI)

Betel-quid chewing













Never

4 (4.0)

277 (38.0)

1.0

1.0

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)

Daily

92 (91.1)

332 (45.6)

19.2 (6.9-52.9)

10.6 (3.6-31.0)

Frequency of chewing (Quid per day)b













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)

Age started chewing b













No chewing

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)

Duration of chewing(yr)b













No chewing

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)

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)

n (%)

Controls

(n= 728)

n (%)

Crude OR

(±95%CI)

Adjusteda OR

(±95%CI)

Alcohol Drinking













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)

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)

Units per weekb













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)

Age started drinkingb













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)

Duration of drinking(yrs)b













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)



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 betel-quid 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 betel-quid 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 only

Both oral cancer and OPMD

Awareness of Symptoms


70.4

20.1

9.4

Awareness of risk factors

Betel-quid chewing

31.8

57.8

10.2

Smoking

64.8

28.8

6.2

Alcohol

81.4

14.7

3.8

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 non-consumers.

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. Development of guidelines for management of oral cancer and OPMD.

  2. Establishment of an island wide surveillance system for oral cancer and OPMD.

  3. Utilization of risk factor model for early detection of oral cancer

  4. Strengthening the ongoing early detection programmes

References

AMARASINGHE, A. A. H. K. (2007) Early detection of oral cancer in the estate sector and the urban areas in the Kalutara district of Sri Lanka: A comparison of utilization of health staff and health volunteers Sri Lanka Dental Journal, 37, 93-98.

AMARASINGHE, A. A. H. K. (2008) The prevalence of risk factors and the level of public awareness of oral potentially malignant disorders in the Sabaragamuwa province of Sri Lanka. MD thesis, Post Graduate Institute of Medicine, Sri Lanka.

AMARASINGHE, H. K., JOHNSON, N. W., LALLOO, R., KUMARAARACHCHI, M. & WARNAKULASURIYA, S. (2010a) Derivation and validation of a risk-factor model for detection of oral potentially malignant disorders in populations with high prevalence. Br J Cancer, 103, 303-9.

AMARASINGHE, H. K., USGODAARACHCHI, U. S., JOHNSON, N. W., LALLOO, R. & WARNAKULASURIYA, S. (2010b) Betel-quid chewing with or without tobacco is a major risk factor for oral potentially malignant disorders in Sri Lanka: a case-control study. Oral Oncol, 46, 297-301.

AMARASINGHE, H. K., USGODAARACHCHI, U. S., JOHNSON, N. W., LALLOO, R. & WARNAKULASURIYA, S. (2010c) Public awareness of oral cancer, of oral potentially malignant disorders and of their risk factors in some rural populations in Sri Lanka. Community Dent Oral Epidemiol, 38, 540-8.

ARIYAWARDANA, A., ATHUKORALA, A. D. & ARULANANDAM, A. (2006) Effect of betel chewing, tobacco smoking and alcohol consumption on oral submucous fibrosis: a case-control study in Sri Lanka. J Oral Pathol Med, 35, 197-201.

ARIYAWARDANA, A., SITHEEQUE, M. A., RANASINGHE, A. W., PERERA, I., TILAKARATNE, W. M., AMARATUNGA, E. A., YANG, Y. H. & WARNAKULASURIYA, S. (2007) Prevalence of oral cancer and pre-cancer and associated risk factors among tea estate workers in the central Sri Lanka. J Oral Pathol Med, 36, 581-7.

ARIYAWARDANA, A. & VITHANAARACHCHI, N. (2005) Awareness of oral cancer and precancer among patients attending a hospital in Sri Lanka. Asian Pac J Cancer Prev, 6, 58-61.

KASTHURIRATHNE, D. A. (2007) Prognostic factors and risk factors for oral cancer. MD thesis, Post Graduate Institute of Medicine, Sri Lanka., .

MINISTRY OF HEALTH SRI LANKA (1990) National Health Policy of Sri Lanka. Colombo.

MINISTRY OF HEALTH SRI LANKA (2009) National Oral Health Survey, Sri Lanka (2002/2003). Colombo, 3rd publication.

NATIONAL CANCER CONTROL PROGRAMME SRI LANKA (2009) Cancer Incidence Data: Sri Lanka Year 2001-2005. Colombo: NCCP. 7th Publication

PETERSON, P. E. (2005) Strengthening the prevention of oral cancer: the WHO perspective. Community Dent Oral Epidemiol, 33, 397-99.



SANKARANARAYANAN, R., RAMADAS, K., THOMAS, G., MUWONGE, R., THARA, S., MATHEW, B. & RAJAN, B. (2005) Effect of screening on oral cancer mortality in Kerala, India: a cluster-randomised controlled trial. Lancet, 365, 1927-33.

WARNAKULASURIYA, K. A., EKANAYAKE, A. N., SIVAYOHAM, S., STJERNSWARD, J., PINDBORG, J. J., SOBIN, L. H. & PERERA, K. S. (1984) Utilization of primary health care workers for early detection of oral cancer and precancer cases in Sri Lanka. Bull World Health Organ, 62, 243-50.


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