Country: Taiwan
Responding officers: Dr.Tien-Yu Shieh, DDS, Ph.D, DNM, FICD, Professor/Specialist of Oral and Maxillo-Facial surgery
Professor of Faculty of Dental Hygiene, Kaohsiung Medical University
Director of Global Center of Excellence for Oral Health Research and Development
Email:
Strategies for Prevention and Control of Oral Cancer in Taiwan
Betel quid chewing is common habit in Southeast Asia, Taiwan, India, Sri Lanka, Southern China, the South Pacific Islands, northern and eastern Africa and among immigrants in UK, other parts of Europe, North America and north-western Australia(1). Almost 10％ of the world 's population, about 600 million, chews betel quid. Thus, it is the world 's fourth most frequently used substance after cigarettes, alcohol and caffeine. (1-2). Of the 267,000 new oral cancer cases in the year 2000 worldwide, 48% (128,000) occurred in the South and South-East Asia (2)
The percentage of oral cancer among all cancers in Asia is much higher than that in the Western countries(3-5％). Investigators have obtained histories of chewing betel quid from patients with oral cancer whose chewing habits are significant and high. Some researchers noted that oral cancer generally develops at the places where quid is grown (2). Some others also stated that betel quid consumption is related to serious adverse health outcomes such as aerodigestive tract and liver cancers (3), metabolic syndrome (4), cerebrovascular accidents (5), heart disease (6) and adverse birth defects (7). The International Agency for Research on Cancer (IARC) has confirmed that betel nut is a Category 1 carcinogen; whereby chewing betel quid with or without tobacco is carcinogenic (2). Despite domestic scholars in Taiwan constantly warn that betel quid chewing is the leading cause of oral cancers, approximately 90％ of oral cancer patients still chew betel quid regularly. Therefore, the risk of developing oral cancer from chewing betel quid is higher than that of smoking and excessive alcohol intake. However, the effect of alcohol drinking, betel quid chewing and cigarette smoking on the incidence of oral cancer vs. the sites of occurrence along with the mean age at diagnosis are quite different(8).
It is now clear that betel quid chewing is considered to be the most important risk factor for oral cancer. By stratified analysis incorporating all three major factors simultaneously, relative risks are estimated at around 122.8 for alcohol, betel quid and cigarette factors as compared with participants abstaining from all three habits (Table1) (3). For this reason, the Executive Yuan of Taiwan adopted suggestions from NGOs to set December 3rd (123) as “Betel Quid Chewing Prevention Day” in Taiwan. The rate of oropharyngeal cancer in Taiwan (10.8 per 100.000) is second only to that in India (12.8-23.2 per 100,000) and is much higher than in Thailand, Philippines and Singapore(9). Although oro-pharyngeal cancer in Taiwan has increased every year, but after-justifying from the age-, period- and cohort-specific incidence only oral cancer has increased while pharyngeal cancer has declined(Table2) (10) over recent years. The 2008 cancer registry data in Taiwan showed that newly diagnosed oral cancer cases in that year were 5,781 (5,349 males and 432 females) with a crude incidence rate of 25.09 per 100,000 people (46.01 for males and 3.79 for females) and a standardized incidence rate of 18.57 per 100,000 people (37.57 for males and 2.97 for females) (Table3). This is considered a substantial amount from epidemiological health point. A comparison of the standardized incidences for all cancers between the genders in 2007 shows that males were 1.4 times more likely than females to develop cancer and were 10 times as likely to develop esophagus and oral cancer, as males were more likely to smoke or chew betel quid (11). As a result, according to the standardized incidence rate, the top 10 cancers in 2008 for Taiwanese were (1) female breast cancer (2) colorectal cancer (3) liver cancer (4), lung cancer (5) prostate cancer (6) oral cancer (7) stomach cancer (8) cervical cancer (9) cancer of the uterus and (10) skin cancer (Table4) (11). Further, based on the records of Department of Health statistics on causes of death, 2,370 Taiwanese died of oral cancer in 2010 (2,198 males and 172 females). The crude oral cancer mortality rate was 10.2 per 100,000 people (18.9 for males and 1.3 for females) while the standardized mortality was 7.8 per 100,000 people (14.9 for males and 1.1 for females)(11). The top 10 causes of cancer death in Taiwan for 2010 were: (1) lung cancer (2) liver cancer (3) colorectal cancer (4) breast cancer in women (5) oral cancer (6) stomach cancer (7) prostate cancer (8) esophageal cancer (9) pancreatic cancer and (10) cervical cancer (11).
In Taiwan, oral cancer risk was the sixth most prevalent cancer in both sexes in 2008 and the fifth highest mortality cancer in both sexes for 2010(11). But in males, oral cancer constituted the fourth most common cancer both in prevalence and mortality rate in 2010. Male oral cancer has become the alarmingly fastest growing cancer in Taiwan with the standardized incidence rate attaining 16% in the past five years (11). Oral cancer is the most common cancer among males between 25 to 44 years old. In 2008, newly diagnosed oral cancer cases already reached 5,781(11), therefore the National Institute of Health Research in Taiwan predicts the incidence of male oral cancer of Taiwan will soon become the top one in the world.
Betel quid chewing not only causes oral cancer but also induces precancerous lesions,the so called oral potentially malignant disorders(OPMDS) (Table5) (12). The OPMDS include hyperkeratosis and epithelial hyperphasia, epithelial dysplasia, erythroplasia and oral submucous fibrosis (OSF), which are the most common oral mucosal disorders in the regions where betel quid chewing is prevalent, such as India, Taiwan, and other Southeast Asia countries. The prevalence of OPMDS show a great variation in an IARC report, the prevalences of leukoplakia and OSF were 0.4-12.9% and 0.0-3.7% respectively(13). In a typical aboriginal community of southern Taiwan, the prevalence of OSF and leukoplakia were 17.6% and 24.4%, respectively (Table6) (12). An oral investigation has shown a more severe public problem than other countries. Meanwhile, there is still a lack of statistics on the country wide prevalence of OPMDs in Taiwan. Since, oral cancer could be preceded by clinically evident OPMDs. It is very important to prevent malignant change in people diagnosed with OPMDs, therefore we must understand the malignant transformation rates of OPMDs; however, the hazard ratios of various OPMDs are not well known at present. From our study, the malignant transformation rate was highest in subjects diagnosed with oral epithelial dysplasia (7.62 per 100 persons/year), followed by verruous hyperplasia (5.21 per 100 persons/year) and in those with hyperkeratosis or epithelia hyperplasia (3.26 per 100 persons/year) (Table7) (14). The hazard rate ratio was 2.41times for tongue lesions when compared with buccal lesions (Table8) (14). In other words, the malignant potential of epithelia dysplasia and verruous hyperplasia are much higher than that of hyperkeratosis or epithelia hyperplasia. Interestingly, finding a lesion located on the tongue appears to be the most important factor affecting malignant transformation of OPMDs.
The prevalence of betel quid chewing among Taiwanese adults from 1996 to 2005 was estimated at 10.9% to 8.47% respectively (males 17.7% to 15.89% and females 1.0% to 0.95%) (Table9); the prevalence of female chewers was much lower than that of males. The number of betel quid users in Taiwan has already topped 1.39 million (11). In 1999 the Betel Quid Association estimated consumption of betel quid of around 80 million grains daily in Taiwan. And they estimated a cost of NT$10 per grain of betel quid, therefore the expenditure of betel quid was approximately $2.7 million daily in Taiwan. While in 2003, the medical expenditure for oral cancer reached high levels and attained an amount of US$90,000,000 (12.3%), which was below the top colorectal cancer (12.7%) (Table10) (15). Betel quid chewing is not only a huge economic burden but also a heavy toll for health insurance expenditure in Taiwan.
In 2005 a national health survey on health risk awareness titled " betel quid itself is carcinogenic", only 47% of interviewed persons answered "agree" (Table11) (16). And for the stage at diagnosis of oral cancer, 40.4% was stage Ⅳ (Table12) (17). It means that people do not appreciate nor realize the danger of oral cancer or oral pre-cancer. Therefore, how to encourage people to detect and mange the lesions of OPMD or to detect an early stage of oral cancer by themselves is far more important than increasing the screening strategy.
Research conducted in India by the WHO showed that visual inspection of the oral mucosa every three years for people over 35 years old who smoke or drink regularly can reduce mortality rates by 43%. While in other studies have reported reductions in oral cancer after conducting projects on quitting tobacco and betel quid chewing (18,19). One study reported that the elimination of betel quid chewing might prevent 62% of leukoplakia and 26% of malignant transformation to oral carcinoma in Taiwan (20). About the factors associated with quitting betel quid chewing, the authors emphasized that education was associated with effort of trying to quit chewing betel quid. Successful quitters of betel quid chewing reported a stronger IHLC (Internal Health Locus of Control scale) (Table13) (21). They also reported that more-educated chewers were more likely to quit than less-educated chewers. Education including both the number of years of schooling completed and supplemental education about the health consequences of chewing betel quid seems to be an important factor for quitting chewing (21).
Most of all, based on those information and data, we have a conclusion that oral health education is very important. Besides the oral cancer screening, we should focus to design an easy method to detect the lesions of OPMD or to detect an early stage of oral cancer for people by themselves.
Following are some strategies and proceedings for prevention and control of oral cancer in Taiwan, and our further researches for quitting of betel quid.
Strategies for prevention and control of oral cancer in Taiwan
1). Objectives
Our objectives are increasing “awareness” to 60%; increasing percentage of screened chewers to 45%; decreasing prevalence of adult chewers to 14% in 2012.
Items 2005 2012
Awareness 47％ 60％
Prevalence
12-18 y/o prevalence 3.2％ 2.9％
18+ y/o prevalence 16％ 14％
Screening
% of screened chewers or smokers 26％ 45％
2). Proceedings
1997-2001
Scheme of the management for betel quid problems
Improve awareness and the reshape/reframe the social norm（continuing）
Create supportive environment（continuing）
2002-2004
Community oral cancer screening program
Provide screening services on a much larger population scale（continuing）
2005-2009
National cancer prevention and control initiatives
Help chewers to quit
Oral cancer prevention and control
Regulations and legislation
Strategies to help chewers quit
1) In conjunct with Association of Oral and Maxillofacial Surgery in Taiwan, a guide book on how to diagnose oral precancerous and oral cancer and what should be assessed for further evaluation will be published.
2) According to the guide book, the Taiwan Dentist Association should provide adequate training to dentists, family physicians and public health nurses for oral cancer screening.
3) Establish a national oral cancer surveillance system.
4) Establish an oral health self-examining activity (include oral cancer examination) such as a new ’333’ activity:
the first ‘3’－oral health self examining ’3’ minutes after teeth brushing in every morning.
the second ‘3’－everyday practice ’3’ minutes of oral health exercise including gnashing teeth, tongue movement, gum massage
the third ’3’－every ’3’ months visiting dental clinic for oral examination
5) Taxation
The Bureau of Health Promotion of the Department of Health would consider planning the possible procedures to include tax from betel-quid chewers. With taxation, the chewers might think to quit the chewing habit for economical reasons. Consequently, chewers’ additional medical expenditure can be avoided.
Further Researches for Oral Cancer Prevention
Topic 1: The epidemiology survey of betel quid related oral lesions
•Specific Aims
(1) A large-scale random sampling survey will be designed to investigate the pattern of betel quid (BQ) use (such as: the prevalence rate of BQ chewing, the type of BQ use and the habits of BQ chewing, etc.) and its related epidemiology analysis
(2) Large-scale epidemiology investigation on the prevalence and risk factors of oral lesion (such as oral submucosa fibrosis (OSF), and leukoplakia)
(3) The development of gene chip (such as: MAO-A, CYP26B1, KLK and ACE genes, etc.) will be applied on the screen prevention of high BQ exposures.
(4) Oral self-examination and health education will facilitate early diagnosis of oral lesions
Topic 2: Development of Betel Quid Dependence Scale; BQDS
•Specific Aims
(1) To estimate the psychometric properties of BQDS applied to the current users, such as OSF patients, taxi drivers.
(2) To investigate the patterns of betel quid/tobacco/alcohol use, and the risk factors of betel quid dependence.
(3) To estimate the prevalence of betel quid dependence, and explore the relationship between betel quid dependence and oral cancer/precancerous lesions.
(4) To design, promote and popularize a self-examination for oral precancerous lesions, and promote the awareness of oral cancer/precancerous lesions among betel quid users.
(5) To design an intervention program for heavy betel quid chewers.
(6) International comparison between Taiwan, India, Sri Lanka and Mainland China.
References:
1. Strickland SS. Anthropological perspectives on use of the areca nut. Addict Biol 2002 Jan; 7:185-97.
2. IARC. Betel-quid and areca-nut chewing and some areca-nut derived nitrosamines. International Agency for Research on Cancer, Geneva, Monograph; 2004; 85.
3. Ko YC, Huang YL, Lee CH, Chen MJ, Lin LM, Tsai CC. Betel quid chewing, cigarette smoking and alcohol consumption related to oral cancer in Taiwan. J Oral Pathol Med. 1995 Nov; 24:450-3.
4. Guh JY, Chuang LY, Chen HC. Betel-quid use is associated with the risk of the metabolic syndrome in adults. Am J Clin Nutr. 2006 Jun; 83:1313-20.
5. Lan TY, Chang WC, Tsai YJ, Chuang YL, Lin HS, Tai TY. Areca nut chewing and mortality in an elderly cohort study. Am J Epidemiol. 2007; 165:677-83. .
6. Guh JY, Chen HC, Tsai JF, Chuang LY. Betel-quid use is associated with heart disease in women. Am J Clin Nutr. 2007; 85:1229-35.