Introduction
Oral cavity and oropharyngeal cancers are the seventh
most common cancers and iconcerning mortality,
the ninth most lethal in the world.[] Annually, the
forecast number of new cases of oral cancer surpass
300.000 cases[] and this disease accounts for about
130.000 global deaths per year.[] Oral cancer is a public health concern, and it is more prevalent in developing
countries than in developed countries.[] With
the exception of skin and thyroid cancers, oral cavity
cancer is the second-most prevalent disease in Turkey
head and neck cancers, after larynx carcinoma.[]
According to the latest data from GLOBOCAN, 1,910
new oral cancer cases were diagnosed and 792 deaths
occurred in Turkey in 2012.[] It was stated that the tongue is the most prevalent oral cancer area in the oral
cavity in Turkey.[] In the literature, however, there is
scant research on oral cancer in Turkey.
Tobacco use, chewing, use of snuff, smoking and
drinking alcohol are the main risk factors related to
oral cancer.[,] Human papillomavirus(HPV16 and
18 infections), immune defects, nutrition and diet,
and socioeconomic background are other risk factors.
[-] Almost 95% of oral cancers occur in people
over the age of 40.[] Although oral cancer may occur
in all locations of the oral cavity, it primarily affects the
language and mouth floor. Oral cancer occurs predominantly
in the form of squamous cell carcinoma. Early
diagnosis of suspected oral lesions, including erythroplakia
and leucoplakia, is the most effective means of
decreasing oral cancer mortality and morbidity.[]
The probability of survival is remarkably higher if diagnosis
in an advanced phase is diagnosed early.[]
The World Health Organization (WHO) Global
Oral Health Programs contains two approaches for
preventing oral cancer: reduction of exposure to risk
factors and early detection through screening.[] In
2007, the WHO's global oral health strategy underlined
that oral health practitioners are involved as part of the
national cancer management program's early detection,
diagnosis, and treatment programs.[] Dentists
and other members of the dental team play a vital role
in decreasing the occurrence of oral cancer by early detection
of the lesions of high-risk patients" oral cancer.
[] While there are various studies worldwide to determine
the understanding and actions of dentists in
oral cancer,[-] there is no comprehensive study
that evaluates the knowledge and attitudes of Turkish
dentists regarding oral cancers. This cross-sectional
study aims to evaluate knowledge and awareness of
oral cancer among dentists in Ankara, Turkey.
Methods
This cross-sectional study was approved by the ethics
committee of the Faculty of Medicine, Afyonkarahisar
Health Sciences University (2019/3-55). Permission was
obtained from the Ministry of Health, Ankara Provincial
Health Directorate, for this study (May 27, 2019-
E.7790). In addition, permission and approval were obtained
from the administration of seven of the nine oral
and dental health centres in Ankara. Two centres were
excluded from this study because they did not approve
the research, and this study was carried out in seven oral
and dental health centres. This study was conducted in
accordance with the Helsinki Declaration principles.
A questionnaire was designed consisting of dentists"
demographic characteristics, knowledge, attitudes,
and practices of oral cancer. Knowledge questions of
the survey were formulated to investigate a dentist"s
awareness of oral cancer epidemiology, risk factors,
symptoms, specific sites and general features of oral lesions.
The validity and reliability of the questions were
confirmed using a pre-test method with a pilot group
of 25 dentists. Dentists working in the oral and dental
health centres were visited and their consent was obtained
for the survey. The questionnaires were applied
to 350 dentists working in seven oral and dental health
centres. Statistical analyses were performed using Statistical
Package for the Social Sciences (SPSS) software
(version 22.0, SPSS, Inc., Chicago, IL). Data were expressed
by frequencies and percentages.
Results
Two hundred ninety-four valid questionnaires were attained
from participants, a response rate of 84%. The
validity criterion was that all the questions in the questionnaire
were read and answered. Therefore, surveys
in which half or fewer of the questions were completed
were considered invalid. The demographic data of the
participants are shown in Table 1. Most of the participants
in this study were male, aged 35 years or more
and married. Approximately three-quarters of the participants
had more than ten years of clinical experience.
Table 1: Demographic characteristics of the participants
Figure 1 shows the number and percentage distribution
of the answers given by dentists to the general
and epidemiological characteristics of oral cancers.
58.5% of the dentists correctly answered the statements
in the survey: "0ral cavity and oropharyngeal cancers
are among the ten most common cancers in the world"
and "Oral cancer has high morbidity and mortality".
However, 75.9% of the dentists did not know that the
five-year survival rate in oral cancer was below 70%.
More than half the dentists erroneously thought that
oral cancers are always asymptomatic and have a good
prognosis. Interestingly, 51% of dentists did not know
that oral cancer is a preventable disease.
Fig 1: Percentage distribution of the answers to questions related to oral cancer.
*: Wrong expressions
Figure 2 illustrates the distribution of correct answers
for risk factors of oral cancer. Concerning risk
factors, a high percentage of dentists correctly reported
the use of tobacco products (93.5%), oral cancer history
(90.1%), use of alcohol (86.7%), exposure to ultraviolet
rays (83.7%), radiotherapy history (82.3%) and human
papillomavirus (HPV) (76.9%) as the risk factors for
oral cancer. However, they incorrectly responded that
obesity (30.6%), spicy foods (17%) and hot food and
drinks (13.8%) were risk factors of oral cancer. Only
about 52.4% of dentists were aware that "old age" plays a
major role in the occurrence of oral cancer.
Fig 2: Distribution of the accurate answers for risk factors of oral cancer.
In the study, it was observed that the correct response
rate in the answers given to the questions about
the clinical features and localisation of oral cancer was quite low. Nearly half of the respondents correctly selected
"squamous cell carcinoma" as the most prevalent
form of cancer in the oral cavity (55.8%) and "leukoplakia"
as the most common premalignant lesion
(44.2%). About 35% of respondents correctly chose
"tongue" as the most common cancer site, and 27.9%
correctly chose the second most susceptible site as the
floor of the mouth for oral cancer. 33.7% of the participants
correctly selected "the ventral lateral margin" as
the most sensitive area of the tongue for oral cancer.
Table 2 illustrates the attitude and behaviour of
the dentists regarding oral cancer. It was revealed that
70.7% of dentists examined the oral mucosa of patients,
47.3% examined the lymph nodes, and 34.7% take a
biopsy of suspected oral lesions. Only 38.1% of dentists
received training on oral malignant and premalignant
lesions before graduation, and 10% had training on
oral cancers in the past five years. Only 29.3% dentists
thought that they had sufficient knowledge about oral
cancer detection and prevention information.
Table 2: Attitudes and practices of the dentists related to oral cancer
Discussion
Dentists have a major role and duty in the prevention
and early detection of oral cancer since it is a disease
that is difficult to recognise in its early stages. Understanding
and evaluating the awareness, attitudes, and
practices of dentists and their efficacy in early detection are significant in reducing oral cancer mortality
and morbidity.[] Therefore, the knowledge and
awareness of dentists regarding oral cancer were evaluated
in this report.
Tobacco and alcohol use are the major risk factors
for oral cancer. In this study, 93.5% and 86.7% of the
dentists consider smoking and alcohol use, respectively,
as a risk factor for oral cancer. Almost all dentists in the
survey conducted in Spain rightly evaluated the use of
tobacco (100%) and alcohol (96.4%) to be the major
risk factors.[] In a survey conducted in Italy, similarly,
tobacco (94.1%), alcohol (79.2%), previous oral
cancer lesions (89.5%), and older age (47.9) were considered
as the major risk factors.[] However, in the present study, only about 52.4% of dentists were aware
that age plays a significant role in the development of
oral cancer. Alaizari and Al-Maweri [] similarly observed
that older age is only suggested as a possible risk
factor for oral cancer by 48% of Yemen dentists. In this
study, only 13.9% of dentists considered the low intake
of vegetables and fruits as a risk factor for oral cancer.
It is also seen that there is a deficit of knowledge that
low intake of fruit and vegetables is also a risk factor.
In this study, obesity (30.6%), hot foods and beverages
(13.8%) and spicy foods (17%) were incorrectly cited
as risk factors for oral cancer. As a result, it has been
revealed that the knowledge of dentists on oral cancer
risk factors is insufficient.
The most common form of cancer in the oral cavity
is squamous cell carcinoma. Although leukoplakia
is the prevalent premalignant lesion, most dysplastic
changes in erythroplakia lesions are detected, rendering
oral cancer examinations a matter of concern.
[] Nearly half of the respondents correctly selected
"squamous cell carcinoma" as the most common type
of cancer (55. 8%), and 44.2% of participants correctly
selected "leukoplakia" as the most common premalignant
lesion. In the study conducted by Kebapçıoğlu
et al.[], 64.1% of Turkish dentists correctly identified
erythroplakia and leukoplakia as premalignant
lesions and 64.7% of the dentists regarded squamous
cell carcinoma as the most prevalent oral cancer type.
In contrast, the study carried out by Lopez et al.[]
indicated that most dentists (90.6%) identified oral
squamous cell carcinoma as the most prevalent form of
oral cancer, which is similar to the percentage observed
among dentists in Yemen,[] Kuwait,[] and North
Carolina.[] Fewer than half of dentists indicated the
tongue (35%) and floor of the mouth (27.9%) as the
most frequent sites of oral cancer in the present study.
In a similar study conducted in Turkey, 37 % of the
dentists indicated the tongue and floor of the mouth as
the most prevalent location of oral cancer.[] This is
of concern because Turkish dentists demonstrate that
they do not have sufficient knowledge of oral lesions
and malignant changes.
Oral cancers can be diagnosed early because they
primarily arise in places that can be seen and easily accessed
through a non-invasive examination. Thus, dentists
should thoroughly examine the patient.[] In the
study, 77.7% of dentists stated that they examined the
oral mucosa completely, while 47.3% stated that they
performed head-neck lymph node examination. Khattab
et al.[] reported that only 26.5% of dentists in
Egypt perform routine lymph-node palpation during
dental visits and that they did so only when there were
patient complaints. In this study, dentists claimed that
they record patients" habits such as smoking, alcohol
or substance abuse (26.2%) and advise patients on risk
factors for oral cancer (48%). In another study, 38.2%
of the dentists in Turkey indicated that their patients
were informed about alcohol and tobacco use is a risk
factor for oral cancer.[] By comparison, in a study
conducted in India, the rate of dentists who informed
the patient about oral cancer risk factors was reported
as 68%.[] Actually, a patient"s visit to the dentist is an
opportunity for them to receive a comprehensive oral
examination and oral health education. Unfortunately,
these deficiencies in information and practice prevent early detection of oral cancers. This study identified
gaps in knowledge among dentists practicing in the
government sector of Turkey.
While early detection is a key factor in improving
the survival rate, most oral malignant tumors are not
diagnosed until they are in advanced stages. Dentists
play a vital role in the early detection and prevention of
oral cancer. Thus, they should conduct cancer screenings
at each patient's visit and pay particular attention to
patients at high risk. As the gold standard for the early
diagnosis of oral cancer is the visual analysis of any oral
epithelial changes, this examination should be a routine
procedure at the oral and dental care centres in Turkey.
Dentists should receive special training on smoking and
alcohol cessation, as dental clinics are ideal places for
smoking cessation interventions. They should perform a
biopsy of suspicious lesions that do not heal within three
weeks or whose cause is unknown. In addition, dentists
should update their knowledge of oral cancers by attending
various training after graduation. Thus, continuous
education and training programs should be organised
on the symptoms of oral cancers, risk factors, treatment
methods and the importance of early diagnosis under
the leadership of the Ministry of Health and the Turkish
Dental Association.
Limitations of the Study
One limitation of this study is that private dentists
are not included. In addition, the dentists have been
selected from only one city, which may limit the generalisability
of findings, although the dental education
curriculum is very similar across the country this study
was conducted.
Conclusion
This study stresses the need for dentist training on risk
factors and early diagnosis of oral cancer in Turkey.
Early detection of suspected oral premalignant lesions
provides the greatest potential to gain control over
oral cancer mortality and morbidity. Thus, oral cancer
screening should also be a standard practice at public
oral and dental health care facilities for high-risk patients.
An additional focus should also be placed on
oral cancer education in Turkish dental schools.
Acknowledgments: I thank the Ministry of Health, Ankara
Provincial Health Directorate and administration of public
oral and dental health centers in Ankara for permission of
the survey. Also, I thank all the dentists who participated in
the survey in this study.
Peer-review: Externally peer-reviewed.
Conflict of Interest: None of the authors have any conflicts
of interest or financial ties to disclose.
Ethics Committee Approval: This study was approved
by the Human Research Ethics committee of the Faculty
of Medicine, Afyonkarahisar Health Sciences University
(2019/3-55). This study was carried out in accordance with
the Helsinki Declaration principles. Informed consent was
obtained from all participants included in this study.
Financial Support: This research did not receive any specific
grant from funding agencies in the public, commercial, or
not-for-profit sectors.
Authorship contributions: Concept - Ö.E.; Design - Ö.E.;
Supervision - Ö.E.; Funding - Ö.E.; Materials - Ö.E.; Data
collection and/or processing - Ö.E.; Data analysis and/or interpretation
- Ö.E.; Literature search - Ö.E.; Writing - Ö.E.;
Critical review - Ö.E.
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