Knowledge and Attitudes of Primary Health Care Dentists Regarding Oral Cancer in Brazil.

OBJECTIVE: The aim of this study was to evaluate the knowledge and attitudes of dentists working in Primary Health Care Units from a Brazilian city, regarding oral cancer.
MATERIALS AND METHODS: A prospective, cross-sectional, epidemiologic survey was performed. Seventy-one dentists from Primary Health Care Units were contacted at their workplace, and participated of the study. Data were collected through a self-administered questionnaire of 31 multiple-choice questions addressing the main clinical features and risk factors for oral cancer. The questionnaire was divided into two sections: questions related to general data and self-perception of the participants regarding personal knowledge of oral cancer, and objective questions related to general information on oral cancer (clinical features, characteristics, traits, and risk factors). The data were tabulated and analyzed by descriptive statistics.
RESULTS: Participants were mostly females (81.5%), less than 40 years of age (57.7%), who underwent training 10-20 years ago (47.9%). Most respondents (66.2%) considered their level of knowledge about oral cancer to be satisfactory. However, only 26.8% of tem felt that they were able to carry out diagnostic procedures for oral cancer. Most of them (95.8%) were interested in participating in training courses on Oral Diagnostics; 56.3% of them reported not having received any training or guidance on how to conduct an examination to detect oral cancer during undergraduate training.
CONCLUSIONS: These findings are consistent with previous reports and point to the need for new public policies to enable early diagnosis of oral cancer and a review of training in Oral Diagnostics in dental schools.

Introduction

Oral cancer is a global health care problem (). There were nearly 300,000 new cases and 145,000 deaths due to oral cancer in the world, reported in 2012 (), making it one of the ten most common cancers (). In Brazil, during 2018–2019, new onset oral cancer is estimated to occur in 11,200 men and 3,500 women. This corresponds to an estimated risk of 10.86 new cases per 100,000 men and 3.28 per 100,000 women ().

The most common risk factors associated with oral cancer are tobacco and alcohol consumption (). However, regardless of the risk factors associated with the disease, the most important factor for patient survival is the stage at which it is diagnosed (). Most oral cancers are diagnosed when clinical signs and/or symptoms are already present. At this point, about 70% of all cases are in an advanced clinical stage (). Lack of patient information combined with inadequately trained health professionals are usually the main reasons for the late diagnosis of oral cancer (). Late diagnosis also occurs because patients of low socioeconomic status have limited access to primary health care ().

The known risk behaviors associated with oral carcinogenesis demonstrate that more than 80% of all oral cancers can be prevented. According to studies around the world, the preventive strategy, especially in developing countries, the goal should be primary prevention, including health education and corrective lifestyle interventions (-, -, ).

A recent Spanish study revealed that the knowledge and attitudes of health care dentists can contribute significantly to changing the current scenario in oral cancer (). An evaluation of the knowledge and attitudes about oral cancer among these professionals is of utmost importance. The information gained from such evaluation may help to assess the need to implement public policies aimed at continued education. Therefore, the aim of the present study was to evaluate the knowledge and attitudes towards oral cancer of Brazilian dentists from Primary Health Care Units.

Subjects and methods

The present study was carried out in the Primary Health Care Units (named Family Health Units), in Recife, Pernambuco, Brazil. A prospective, cross-sectional, epidemiologic survey was performed. The study was approved by the Local Research Ethics Committee (protocol l# 29642314.6.0000.5208).

The study was performed between February and June, 2015. The sample included 71 dentists, who consented to participate and answered the questionnaire. All participants were selected by random sampling. The dentists who were confined to administrative tasks were excluded from the survey.

The registry and data collection were carried out by means of a self-administered questionnaire of 31 multiple-choice questions addressing the main clinical features and risk factors for oral cancer. The questionnaire was divided into two sections: 1) Questions related to general and demographics data of the participants (age, gender, time since graduation, attitudes towards patients with oral cancer and self-perception regarding personal knowledge of oral cancer); and 2) Objective questions related to general information on oral cancer (clinical features, characteristics, traits, and risk factors). The questionnaire also included questions related to potentially malignant disorders of the oral cavity.

The objective of the present study was explained before the study was commenced. Data confidentiality and the right to leave the study at any point of time were ensured by consenting to the terms of the study. All participants signed the informed consent form. In addition to verbal explanation and description of the study, each participant received a copy of the informed consent form along with the self-administered questionnaire.

A statistical analysis was carried out using the SPSS ver. 20.0 software (Statistical Package for the Social Sciences, Chicago, IL, USA). Descriptive statistics were obtained for variables including age, time since graduation, attitudes towards patients with oral cancer, and self-perception regarding personal knowledge of oral cancer (clinical characteristics, traits, and risk factors). The variables of “time since graduation” and “self-perception regarding personal knowledge about oral cancer” were compared to other variables using the chi-square test (p ≤ 0.05).

Results

General characteristics of the studied population

The study sample comprised 71 dentists, 58 females (81.7%) and 13 males (18.3%). Most of them were 40 years old or less (31 – 57.7%). Thirty-four (47.9%) participants had graduated 10-20 years ago, 28 (39.4%) had graduated more than 20 years ago, and 9 (12.7%) had graduated less than 2 years ago. There were only 3 smokers (4.2%) among the participants.

Clinical features of oral cancer

Regarding the clinical findings related to oral cancer, 47 (66.2%) participants indicated that squamous cell carcinoma was the most common type of oral cancer. Fifty-one (71.9%) contributors indicated that the tongue and the floor of the mouth were the most frequent sites of oral cancer, while 7 (9.8%) did not respond to this question. Sixty-six dentists (93%) indicated that oral cancer most commonly affects patients over 40 years old, and 54 (76.1%) also indicated that oral cancer is more frequently diagnosed at an advanced clinical stage (Table 1).

Table 1

– Distribution of the answers regarding clinical features of oral cancer

Variables		n (%)
What is the most common type of oral cancer?	Squamous Cell Carcinoma	47 (66.2)
	Mucoepidermoid carcinoma	3 (4.2)
	Ameloblastoma	3 (4.2)
	Kaposi Sarcoma	2 (2.8)
	Lymphoma	1 (1.4)
	Do not know	15 (21.1)
What is the most common site affected by the oral cancer?	Tongue/Floor of mouth	51 (71.9)
	Buccal mucosa	8 (11.2)
	Palate	3 (4.2)
	Gum	2 (2.8)
	Do not know	7 (9.8)
What is the most age group affected by the oral cancer?	Under 18 years	0 (0.0)
	Between 18 and 40 year	2 (2.8)
	Above 40 years	66 (93.0)
	Do not know	3 (4.2)
What is the most frequent clinical stage in which the oral cancer is diagnosed?	Initial	7 (9.9)
	Advanced	54 (76.1)
	Do not know	10 (14.0)
Which of the following diseases are commonly related with the development of oral cancer?	Leukoplakia	61 (85.9)
	Candidiasis	4 (5.6)
	Stomatitis	3 (4.2)
	Pemphigus vulgaris	1 (1.4)
	Geographic tongue	0 (0.0)
	Do not know	2 (2.8)

Risk factors associated with oral cancer

Most participants indicated that tobacco (71, 100%), alcohol (70, 98.6%) consumption, exposure to sunlight (69, 97.2%), and family history (68, 95.8%) were risk factors for oral cancer. Emotional stress, and low intake of fruits and vegetables were indicated as risk factors by 56 (78%) and 42 (59.2%) participants, respectively. Ill-fitting prostheses (63, 88.7%), deficient oral hygiene (56, 78.9%), and the presence of tooth decay (56, 78.9%) were also identified as risk factors for oral cancer. Oral sex and parenteral drug abuse were identified as risk factors for oral cancer by 36 (50.7%) and 15 (21.1%) dentists, respectively (Table 2).

Table 2

– Absolute and relative distribution of the answers regarding risk factors for oral cancer

Variables		n (%)
Parenteral drug abuse	Yes	15 (21.1)
	No	56 (78.9)
Alcohol consumption	Yes	70 (98.6)
	No	1 (1.4)
Tobacco consumption	Yes	71 (100.0)
	No	0 (0.0)
Family history of cancer	Yes	68 (95.8)
	No	3 (4.2)
Emotional stress	Yes	56 (78.9)
	No	15 (21.1)
Low vegetables and fruits intake	Yes	42 (59.2)
	No	29 (40.8)
Oral sex	Yes	36 (50.7)
	No	35 (49.3)
Ill-fitting prostheses	Yes	63 (88.7)
	No	8 (11.3)
Deficient oral hygiene	Yes	56 (78.9)
	No	15 (21.1)
Presence of decay teeth	Yes	53 (74.6)
	No	18 (25.4)
Solar exposure	Yes	69 (97.2)
	No	2 (2.8)
Hot food and drink	Yes	33 (46.5)
	No	38 (53.5)

Clinical practice related to the oral cancer

When asked about performing physical examination to identify the presence of oral lesions, 70 (98.6%) of them confirmed this practice at the first appointment. Regarding further course of action when an oral lesion was identified, 67 (94.4%) participants stated that they would refer the patient to a specialist in Oral Diagnosis, two (2.8%) would refer to a specialized hospital, and two (2.8%) would confirm the diagnosis themselves.

Knowledge of oral cancer, interest, and perception

On analysis of the general features of oral cancer, 47 (66.2%) participants considered their knowledge to be adequate. Nineteen (26.8%) dentists stated that they were confident to carry out diagnostic procedures related to oral cancer. Most study participants (60 – 84.5%) pointed out that their patients were not well informed about preventive procedures and general features of oral cancer.

Forty (56.3%) participants stated that they never received any information related to the diagnosis of oral cancer during undergraduate training. Thirty-six (50.7%) participants had not enrolled in any continued education course during the previous two years. However, the majority (68, 95.8%) expressed interest in undergoing continued education courses in the future. Moreover, 70 (98.6%) participants acknowledged the importance of dentists in the prevention and early diagnosis of oral cancer.

Statistical analysis did not show any significant association between the time since graduation and self-perception regarding personal knowledge about oral cancer and the other variables (p= 0.2).

Discussion

The incidence of and death rate due to oral cancer can be minimized if adequate measures are undertaken to enable prevention, early diagnosis, and expeditious treatment (). In general, dentists are expected to have adequate knowledge on the risk factors and clinical features of oral cancer, regardless of its implementation in public health or private practice. However, there are some indications, such as the persistence of oral cancer as a major health problem, that this assumption may not have been fulfilled in routine primary care dentistry or in private practices.

Most of the participants were 40 years old or younger. Therefore, it is a young population having a long professional career ahead, which requires further education, to enable prevention and early diagnosis of oral cancer. With respect to professional experience, 47.9% of participants were between 10 and 20 years, 39.4% were more than 20 years, and 12.7% were up to 2 years since graduation. Based on the above information regarding professional experience, it would appear that a significant number of participants would be confident of carrying out clinical procedures to diagnose oral cancer. However, only 26% of dentists expressed such confidence. The absence of association between duration since graduation and the other variables studied shows that some participants assumed to have a good knowledge of oral cancer even though their responses to the questionnaire did not support this claim.

In the present study, 66.2% of the participants pointed out that squamous cell carcinoma was the most common type of oral cancer, while 33.8% did not know or answered incorrectly. Another study revealed that 18.4% of surveyed dentists were unaware of the most common type of oral cancer (). This is of concern, because it shows a lack of knowledge of the biological behavior of the tumor, apart from likelihood of compromising the initial oral examination of patients.

The primary health care dentists correctly pointed out that the tongue and the floor of the mouth were the most common sites for oral cancer, with most tumors affecting patients above 40 years old, which is similar to the findings from other studies (). Among the potentially malignant disorders, leukoplakia is the most prevalent, with a 5% malignant transformation rate (). The role of the dentist is of utmost importance in the diagnosis and education of the patient with leukoplakia. The present study showed that 85.9% of the participants identified leukoplakia as the condition most commonly associated with oral cancer, as observed in another survey ().

The first preventive measure against oral cancer relies on the awareness of patients and dentists about the risk factors associated with the disease (). Alcohol and tobacco consumption are the most important risk factors related to oral cancer, with an incremental risk when both are used concomitantly (-). The proportion of smokers (80%) among patients with oral cancer is two to three times higher than in the general population, with increasing risk depending on the number of cigarettes smoked per day and the duration of smoking. Similarly, one third of men with oral cancer have a history of heavy alcohol consumption (). Similar to previous studies (, , ), alcohol (98.6%), smoking (100%) and exposure to sunlight (97.2%) were the most frequent risk factors stated by the participants. In the current survey, low intake of fruits and vegetables was pointed out as a risk factor for oral cancer by 59.2% of participants. Epidemiological studies have shown a two-fold increase in the risk of oral cancer with low intake of fruits and vegetables (). Moreover, Toporcov et al. () showed that consumption of fruit and vegetables can mitigate the harmful effects of smoking. Thus, education in dietary habits may also be an important factor in the prevention of oral cancer.

Deficient oral hygiene (78.9%) and tooth decay (74.6%) were pointed out as risk factors for oral cancer by a large number of participants. Even though other studies have revealed similar results (-), it is difficult to establish a cause and effect relationship between these factors and the development of oral cancer. There is no agreement in the literature whether deficient oral hygiene and the presence of tooth decay may expose the patient to a higher risk of developing oral cancer. Similar reasoning can be applied to ill-fitting prostheses, identified as a risk factor for oral cancer by 88.7% of participants in the present study. Some authors suggest that microorganisms present in the oral cavity produce carcinogenic acetaldehydes that potentiate the effects of alcohol and tobacco (, ). Moreover, most of the Brazilian populations do not have access to adequate dental treatment; hence, poor general oral hygiene is usually observed ().

The Human Papilloma Virus (HPV) causes approximately 5.2% of cancers in humans, including rectal, genital, oropharyngeal, and cervical cancer. While epidemiology and correlation between HPV infection and oropharyngeal cancer is well established, many factors remain unknown regarding the association between HPV oral infection and oral cancer. Despite the limited knowledge of the epidemiology, natural history and prevention of HPV oral infection, studies show that the infection is sexually transmitted and is related to the development of some cases of oral cancer (). It is established that approximately 5% of cases of oral cancer are related to HPV infection (, ). Although the incidence of HPV-induced oral cancer is low, dentists can guide patients on the risks of unprotected oral sex. On the other hand, the populations surveyed were under the mistaken impression that emotional stress is a risk factor for oral cancer, a finding similar to that observed in another survey ().

Most oral cancers are diagnosed at an advanced clinical stage (). In the current study, 76.1% of the participants were aware of this fact, which is similar to the findings observed in another survey (). Diagnostic delay may be attributed to factors associated with the patient (patient delay) or practitioners (professional delay). Although it is variable, patient delay has been reported to be approximately six months. It is estimated that patient delay of more than 3 months significantly worsens the prognosis (). The two main components of national cancer control programs are information for the public and professionals. However, in the present study, 84.5% of the participants stated that patients are not well informed on the preventive and diagnostic aspects of oral cancer. Other factors related to the diagnostic delay of oral cancer were the limited access to primary health care for patients of low socioeconomic status, and irregular dental follow-up (). The diagnostic delay is also related to the lack of knowledge of dentists regarding identification of oral lesions. The professional delay varies between one and five months. Oral examinations are limited to teeth and gums, and lack of knowledge of oral mucosal lesions, may be factors associated with delay in diagnosis of oral cancer (). In the current survey, 66.2% of the dentists indicated a satisfactory knowledge regarding this; however, only 26.8% of them stated that they were confident enough to carry out diagnostic procedures related to oral cancer, as reported in other studies (, ). It is important to point out that dentists should undertake the responsibility of their role in the prevention and diagnosis of oral cancer. The majority of dentists (98.6%) reported that their participation is essential in these processes.

During undergraduate training, 56.3% of dentists stated that they did not receive any information on how to perform a clinical examination to screen for oral cancer. These data are alarming, which suggests that during undergraduate training, adequate emphasis should be put on identifying oral lesions, especially oral cancer. The dentist should make a difference by combining theoretical knowledge with clinical skills to facilitate the early diagnosis of oral cancer. Hence, undergraduate training in dentistry and continued education courses should focus on the identification and prevention of oral cancer and other potentially malignant disorders. These measures are of utmost importance in decreasing morbidity and mortality due to oral cancer (). Currently, the need for continued education is a prerequisite for professional performance, since new information and technological advances make the knowledge acquired during undergraduate training outdated within a short period of time (). There is a need for regular education programs meant for updating the knowledge level of professionals (, ). However, 50.7% of participants stated that they did not subscribe to a continued education course for more than two years. On the other hand, most of them (95.8%) showed a keen interest in such courses in the future, as was previously mentioned ().

Conclusion

In this study, dentists from Primary Health Care Units in Brazil did not express a level of confidence required for the diagnosis of oral cancer. In addition, a questionnaire with open-ended questions could reveal even more worrying results. This calls for a change in educational and training programs on oral cancer during undergraduate dentistry courses. This will result in an increased number of trained professionals, capable of correctly diagnosing this disease. Moreover, public health care policies need to be revised to reduce morbidity and mortality due to this disease.