In Hungary, the incidence and mortality from oral cancer is so high, that in the past decades it has attracted international attention. The mortality rates are the highest in Europe. As risk factors, smoking and alcohol drinking have a multiplicative role; in addition, a number of dental factors also play a role. Premalignant conditions and lesions are well known. They should be targeted for early detection and early treatment. The screening tool is simple: inspection and palpation. The physician-patient encounters provide opportunity for screening. This paper looks for the answer to the long debated question: who is responsible for oral screening?
“Oral cancer” is a collective term. The International Classification of Diseases (ICD-O) lists under this heading the tumors of the lips, oral cavity, the pharynx, and the not otherwise specified anatomical sites of the oral cavity (C00-C14), with the exception of the malignant tumors of the parotid gland (C07), major salivary glands (C08), tonsils (C09) the sinuses (C31) and the larynx (C32). In this paper, we are dealing with those tumors that are traditionally referred to as “cancers of the oral cavity”. It is justified to discuss these as the same group of cancers because (*) “oral cancers” arising in mucous membranes of the mouth (i.e. lip. the base of, tongue, gum, floor of mouth and plate, and other unspecified parts of mouth) and pharynx (comprising the oropharynx, hypopharynx and nasophasynx) are squamous cancer of various degrees of differentiation; (*) the same risk factors play a role in their development; (*) they have a lot in common in the natural history and course of these diseases; and (*) due to their anatomical site they are easily accessible for early detection and early treatment, therefore they lend themselves to screening.
In 2012, according to the World Cancer report, 530.000 new oral cancer cases were diagnosed, and 290.000 deaths were registered world-wide. Two-thirds of new cases are reported from the low-, and lower-middle income countries [
Mortality rates show major changes over time. It is most striking in Central and Eastern Europe, where there has been approximately a doubling in death from oral cancer. Dramatic rising trends are reported from Hungary. In this country, the mortality from oral cancer has been the highest in the European countries. According to the Central Statistical Office, between 1948 and 2004 the all cancer mortality increased by 2.8 fold, but the mortality from oral cancer increased by 6.8 fold [
According to the definition of classical epidemiology, the “cause of a disease” is a factor which is necessary and, at the same time, sufficient to develop a disease. As a contrast to the infectious diseases, the causes of cancer, that of the causes of oral cancer, in particular, are not sufficiently understood. Epidemiological evidence, however, has suggested that many different factors are not necessarily causal agents but are associated, individually or in combination, with an increased probability, or risk of the occurrence of these cancers. These factors are named as “risk factors”.
In the case of oral cancers, the majority of risk factors are lifestyle-dependent. In this context, lifestyle is defined as “as a set of personal decisions on which the individual has more or less influence” [
In the development of oral cancers the physical-chemical irritation of tobacco smoking and heavy alcohol consumption are well established risk factors. The most comprehensive sources of epidemiological evidence are available in the IARC publications on the subject [
The evidence relating to certain dietary components and the risk of cancer is inconsistent. Dietary deficiencies or imbalances may also play a causative role as high as 10% - 15% of cases [
Chronic mucosal trauma resulting from sharp teeth, dentures, poor oral hygiene, unhealthy diet, or implants has frequently been associated with the development of oral cancer [
Recently, several studies have investigated the prevalence of HPV in oral cancers. The possible causal role of HPV was first indicated by Gillison and co-workers, [
Oral cancers are more prevalent in lower socioeconomic groups of the population [
In general, “precursor”, or premalignant lesion means a condition preceding the pathological onset of cancer. It has no necessarily causal relationship with cancer; notwithstanding, it is considered as an indicator of the increased risk for cancer development.
In stomatology, precancerous conditions and precancerous lesions are distinguished [
According to the state-of-the-art of medical and other related sciences, the most promising strategy for alleviating the burden of oral cancer are disease prevention in the long run, and screening in short- and medium term.
With regards to primary prevention, there are plenty of opportunities for primary prevention, i.e. for the prevention of cancer from developing, by eliminating the risk factors, most of which are lifestyle-dependent, by means of health education and regulatory measures. Nevertheless, reducing incidence through primary preventive program and by health promoting measures is likely to be a long-term undertaking, and is not promising anyway as “bad habits die hard”. According to educated guesses, in such a way, the incidence of oral cancers might be reduced by some 60% - 80%. When primary prevention fails, early detection through screening and relatively inexpensive treatment can avert most deaths.
The target-population of screening is the healthy or apparently healthy persons who consider themselves healthy but, in fact, they are sick for some latent, symptomless disease. The rationale for screening is that oral cancer may be preceded by a clinically detectable potentially malignant lesion (leukoplakia or erythroplakia) or that it may begin as a small, localized, often asymptomatic lesion in the early part of its natural history The target condition of screening is any risk factor that has a role to play in developing a disease, any premalignant lesions that proceed the disease, or an early stage cancer.
The main purpose of screening is to rule out or to raise the probability of some disease. Screening methods are not suitable for establishing a final diagnosis; that is the task of a clinical procedure which needs to follow the screening. Thanks to screening, the treatment might start much earlier than it would have happened without screening. Thus, it is fair to say that screening might improve both the life expectancy and quality of life of those who attend it.
The earlier detection of a disease followed by early treatment might prevent the fatal outcome. Screening of a high risk population might detect of a significant number of oral cancers, most of them still in a stage suitable for treatment [
Thanks to their anatomical location, the pathologies of oral cavity can be seen by the naked eye, and palpated by hands; therefore, the screening tools for oral screening are simple: inspection and palpation [
As is widely known, there are two screening models used in the health care system: organized and opportunistic ones [
Up until now, there is only one properly conducted randomized controlled trial that has used mortality as the primary outcome. This oral cancer screening trial was a community-based cluster-randomized control trial carried out in North Trivandrum, Kerala, India from 1996-2008, where in 7 regions randomizes trials had been carried out, and another 6 regions served as controls. In the screened population, inspection by trained personnel every three years was the screening tool. In the twelve year follow-up, 138 deaths from oral cancer (14.4/100.000) in the screened arm, and 154 cases (17.1/100.000) in the control group was reported [
Several large population screening programs from developing and smaller studies from developed countries had been reported over the years, but all failed to provide evidence of effectiveness, in term of mortality reduction [
Some of the obstacles include the relative rarity of the disease, a lack of knowledge of the natural history of the disease, disagreement over disease management and the lack of evidence on the efficacy and cost-effectiveness of different screening methods [
Opportunistic screening for oral cancer and precancer in general dental practice is a realistic alternative to population screening, as patients attending the practice are representative of the general population, both in terms of lesion prevalence and high risk habits such as smoking and drinking. The study of Lim et al demonstrates that opportunistic screening for oral cancers by general dentists is feasible and worthwhile [
Although the blame for the detection of early oral cancer and its precursors is passed to the general dental practice, experience shows that if every patient attending the dental practice would be carefully screened, the opportunistic oral screening would not bring the desired results, and would not be cost-effective [
Some argue that those persons at highest risk for oral cancers do not seek dental services. In fact, low socioeconomic status is significantly associated with increased oral cancer risk in high and lower income-countries, across the world, and remained so when adjusting for potential behavioral confounders. Inequalities persist but have perhaps been decreasing over recent decades. Oral cancer risk associated with low socioeconomic status is significant and comparable to lifestyle risk factors [
Of all health providers, general dentists are the most logical group to perform screening for these cancers. However, individuals who are at greatest risk rarely visit a dentist; they are more likely to consult general medical practitioners. Therefore, they could have an important role in the early detection of oral cancer. Research has shown that general practitioners do not opportunistically screen high-risk individuals; however, the barriers to screening are poorly understood [
The educational needs of primary care-givers including dentists, and general practitioners must be addressed and the difficulty of reaching high-risk groups is still there [
Oral cancers are an increasing public health problem. At present, most of the oral cancer patient turns to a doctor at a late, advanced, neglected state when the tumor is already incurable [
Several reviews examine whether oral cancer risk is associated with low socio-economic status. In a meta-analysis by Warnakulasuriya, four out of the 37 studies provided data on the association of education with oral cancer risk, and concluded that high educational levels were associated with an increased risk for oral cancer [
Analyses have shown that low socioeconomic status was significantly associated with increased oral cancer risk in high and lower income-countries, across the world, and remained so when adjusting for potential behavioral confounders. Inequalities persist but have perhaps been reduced in recent decades. Oral cancer risk associated with low socioeconomic status is significant and comparable to lifestyle risk factors. The results provide evidence to steer health policy which focus on lifestyles factors toward an integrated approach incorporating measures designed to tackle the root causes of disadvantage [
The association between human behavior patterns and the development of oral cancer is widely recognized. Most oral cancer cases and deaths are due tothe exposure to carcinogens caused by lifestyle behaviors such as tobacco smoking, betel liquid or tobacco chewing, alcohol intake, and micronutrient deficiencies. The purpose of the reviews is to provide insights into the social and behavioral factors associated with the development of oral cancer. These lifestyle factors and behaviors are considered the downstream determinants of oral cancer, while the upstream determinants are those which are common to all cancers such as the community level environmental factors, industrial pollution and contamination, access to the health care system, health insurance, and quality of health care, which are all dependent on the socioeconomic status of the individual. It was concluded that, since the incidence of oral cancer is greatly impacted by behaviors that can be modified, the impact that these behaviors―as well as other social determinants―have on oral cancer and its outcome needs to be addressed by society. The more vulnerable patients seem generally unaware of the risk of oral cancer screening or are reluctant to accept the offered screening; therefore, future awareness and screening effort should be directed at the yearly screening of higher risk, more vulnerable populations [
1) Who is responsible for oral screening?
The question to be answered: who is responsible for oral screening, and whose task is it? No doubt, primarily, oral screening should be the task of general dental practices, but most of the dentists do not pay sufficient attention to the prevention of the oral precancer (leukoplakia, erythroplakia) and cancers, and to their detection in a complaint-free state―in spite of the fact that, in most countries, there are regulations making the stomato-oncological screening of their patients mandatory [
Most general dental practitioners were adequately aware of oral screening and biopsy procedures but felt reluctant to perform them, which suggests that dental education programmes are needed for them in oral pre-cancer/cancer detection as well as screening and diagnostic procedures.
The dental hygienist is a primary resource for oral cancer screening and prevention. In more and more countries, there is regular education and training for “dental hygienists” or “oral hygienists” through dental schools or universities [
Primary care physicians are well suited to providing examinations of oral cancer, and to screening for the presence of suspicious oral lesions, and referral of suspicious patients to specialists for biopsy could be expected from them. However, they generally do not regard oral screening as their task.
In a study investigating the symptoms associated with cancer of the oral cavity and exploring the role of general practitioners in the identification and referral of patients, a questionnaire was sent to 200 patients on the route to diagnosis, symptoms, delay in presentation, and outcomes of consultations with their general practitioner. Of 161 respondents, over half (56%) had been referred to secondary care by their general practitioner, and one-third (32%) by their dentist. The most commonly reported symptoms were a mouth ulcer (32%), a lump in the face or neck (28%), and pain or soreness in the mouth or throat (27%). Fifteen per cent delayed presentation for more than 3 months. After consultation with a general practitioner, (n = 109), 53% were referred to a specialist, 22% were referred for tests, 12% were told that their symptom was not serious, and 12% were treated for another condition. General practitioners have an important role in the identification and referral of people with oral cancer, and the clearly recognized symptoms identified in this study can be used to aid assessment and decision-making. Interventions to promote the prompt identification of oral cancer in general practice such as the opportunistic screening of high-risk patients may help to improve the poor survival rates [
2) Attempts to screen
In Hungary, the burden of the disease is high, the highest in Europe, therefore screening for oral cancer is a major issue. During the past decades, zealousstomatologists conducted several opportunistic stomato-oncological screening campaigns; the summary of these was published Bánóczy et al. Out of some 20.000 examinations 0.12% oral cancer and 2.63% precancerous lesions were detected [
Unfortunately, the target population of oral screening is not “regular” for either the dental or the general practitioner’ office. It is estimated that about half of the population regularly visit a general dental practice, most of them only in case of toothache; three-fourth of patients with leukoplakia go to the doctor, but only with complaints [
1) The average population is unaware of the risk factors and early signs of oral cancer, therefore health care personnel’s task is to provide all information, and to encourage people to see a doctor if they have any complaints indicating any oral disorders. This is a challenge for health education. In the message of health education, the information on the importance and availability of oral screening, as well as the possible role of HPV in the development of the oral cancer, all needs to receive greater emphasis.
2) One must strive for an annual screening of high-risk individuals. In order to reach them, cooperation has to be established with those authorities and non-governmental (civil) organizations whose task is to take care of the disadvantaged persons.
3) In undergraduate and postgraduate education and training of dentists, dental hygienist, physicians, and general practitioners, in particular, a major emphasis has to be given to the risk factors and early signs, the prevention and screening of oral cancer.
Oral cancer―due to its frequency and role in cancer mortality―is a major public health problem. The majority of oral cancers are discovered at an advanced stage; the ratio of advanced cases has not decreased in the last 40 years. The knowledge and opportunities of primary prevention and early detection or screening is not sufficiently applied; this is one of the “plague-spots” of health care in most countries; something must be done about it. If those in the general dental practice and primary care would apply themselves to the task more, the decrease of the burden of oral cancer on society would become a realistic goal.
Döbrőssy, L. and Lapis, K. (2018) Screening for Oral Cancer 2018. Journal of Cancer Therapy, 9, 465-479. https://doi.org/10.4236/jct.2018.96039