Introduction

The global incidence of lip and oral cavity cancer is estimated at 4 cases per 100,000 people [5]. For the triennium 2020–2022, the estimated number of new oral cancer cases in Brazil was 11,180 for men and 4010 for women. This estimation positions oral cancer as the fifth most common cancer in men and the thirteenth most common in women [6]. Among malignant neoplasms, squamous cell carcinoma (SCC) is the most prevalent, accounting for over 90% of oral cancer cases [11]. The segment of the population most affected is men over 40 years old. Studies indicate that the most significant risk factors for the disease are tobacco use, alcohol consumption, and HPV [24].

The diagnosis of the disease should not pose difficulties, given that the examination to identify suspicious lesions is relatively straightforward and the mouth is an anatomically accessible region. However, a significant portion of generalist dentists perceive themselves as unprepared to deal with diagnosing oral diseases, explaining why a substantial number of these professionals do not routinely perform comprehensive oral examinations [20]. This insecurity reported by many dentists leads to numerous referrals for specialized stomatology care. In the realm of public health, this fact burdens secondary and tertiary care, potentially causing delays, hindering early diagnosis, and impacting the management of potentially malignant or malignant diseases requiring prompt attention [4, 21].

The dentist plays a crucial role in oral cancer prevention and early diagnosis. Conducting early-stage diagnoses enables faster oral cancer treatment, a fundamental factor in reducing the morbidity and mortality of affected patients [10]. Over recent years, early detection of oral cancer has remained an unachieved goal in most cases, despite its crucial importance for achieving a favorable prognosis. Thus, dentists should possess a high level of knowledge and the ability to recognize the disease at its various stages [1]. Given that the teaching time during dental education seems inadequate, continuous education initiatives could serve as an alternative to bridge this gap [2], aiming to enhance the diagnostic skills of these professionals along with their confidence in managing this significant disease.

The objective of this study was to evaluate the knowledge, attitudes, and practices of dentists from various regions of Brazil regarding oral cancer and their self-perceived confidence in dealing with the subject.

Materials and Methods

Experimental Design, Sample, and Ethical Considerations

This cross-sectional analytical study enlisted participation from dentists across various regions of Brazil, all registered on the TelessaúdeRS-UFRGS platform. This project received approval from the Research Ethics Committee of the Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul (CAAE: 30,423,220.4.0000.5327/ project number: 4.012.220).

All dentists registered on the TelessaúdeRS-UFRGS Platform were invited to take part in this study, constituting a census-like sampling. The email invitation included a link to access the Informed Consent Form and the questionnaire for gathering data about participants and addressing questions regarding their knowledge, attitudes, and practices concerning oral cancer.

Data Collection

The survey was conducted using a questionnaire developed on the Google Forms platform. An email invitation, containing the Informed Consent Form and the questionnaire, was dispatched to dentists enrolled in TelessaúdeRS-UFRGS courses. Those enrollees who answered the questionnaire within three months of the email invitation (July, August and September 2021) were included in the study database.

Before engaging with the questionnaire, dentists agreed to an informed consent form. By indicating their willingness to participate in the study, dentists were directed to the actual questionnaire. The initial section of the questionnaire consisted of inquiries about participant characteristics such as gender, age, region of origin in Brazil, educational level, years since graduation, type of educational institution attended, and field of practice. The second part encompassed questions related to clinical approach, knowledge about oral cancer risk factors, clinical and epidemiological aspects of oral cancer, as well as self-perception and the need for updates on the topic.

Data Analysis

Statistical analysis was performed using SPSS 25.0 software (Statistical Package for the Social Sciences Inc., Chicago, IL, USA). Quantitative variables were presented as means and standard deviations, while qualitative variables were displayed as absolute values and percentages (%). The association among some variables was assessed by means chi-squared test. For that analysis, the p-value was set at 5%

Results

Sample Characteristics

A total of 1334 dentists responded to the questionnaire. Among these, those who did not complete at least 60% of the information or were not originally from Brazil (n = 43) were excluded, resulting in a final sample of 1291 participants. The majority of participants were female (n = 974, 75.0%). The mean age of participants was 36.28 (± 10.5), ranging from 21 to 72 years. The Brazilian regions with the highest number of participants were the southeast (37.33%) and the south (27.03%). Further details regarding the sample characteristics can be observed in Fig. 1 and Table 1.

Fig. 1
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Experiences and self-perception of respondents regarding to knowledge, training, and capacity for diagnosing oral cancer

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Table 1 Demographics of the sample
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Knowledge About Oral Cancer

Regarding the inquiries concerning knowledge of oral cancer, the majority of dentists displayed current awareness. A total of 89.1% of them correctly identified squamous cell carcinoma as the most prevalent form of oral cancer manifestation, whereas 2.8% erroneously cited ameloblastoma. A substantial portion adeptly recognized the tongue (77.8%), lower lip (73%), and floor of the mouth (57.7%) as the most frequent sites of disease occurrence. The majority of dentists were capable of recognizing leukoplakia (84.4%), actinic cheilitis (64.7%), and erythroplakia (62.8%) as potential malignant disorders. A considerably high number (45.5%) of professionals mistakenly indicated traumatic diseases as conditions with a risk of malignant transformation, whereas only 39.9% of them included lichen planus in that group of conditions. Data about knowledge of oral cancer are depicted in Table 2.

Table 2 Knowledge of dentists regarding oral cancer charactetistics
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Practices and Self-perception of Dentists Regarding Oral Cancer

A total of 91% of dentists reported routinely conducting a comprehensive oral examination. Among those who admitted not adopting this practice, the primary reasons cited were lack of time (67.8%), insufficient knowledge (17.4%), and deeming it unnecessary (11.3%). Within the percentage of participants who indicated not routinely performing mucosal examinations in clinical practice, 71.3% affirmed conducting the examination when the patient is at high risk (smoker and/or alcohol consumer).

Approximately 82% of dentists asserted feeling informed or well-informed regarding the recognition of the clinical characteristics of the disease. The experience of examining patients with oral lesions is prevalent (89.3%), although only 45.5% have performed a biopsy on any oral lesion (Fig. 1).

Regarding preparedness to handle oral cancer, 64.5% of study participants find the training received during their undergraduate course for diagnostic procedures insufficient, and 48.6% affirmed a lack of confidence in detecting the disease.

Impact of Years Since Graduation

Dentists who graduated for more than 8 years exhibited a significant association (p < 0.01, chi-square test) with considering traumatic lesions as situations with a risk of malignant transformation (56.1%), compared to those who graduated more recently (44.5%). The same trend was observed concerning the perception of being adequately trained to examine for identifying oral cancer. Among dentists who graduated for over 8 years, 71.4% reported not feeling adequately trained, while among dentists with fewer years since graduation, the same sentiment was expressed by 57.7% (p < 0.01, chi-square test).

Discussion

This study sought to assess the level of knowledge, attitudes, and practices of dentists from different regions of Brazil concerning oral cancer, along with their perceived self-confidence in the subject matter. Despite being the fifth endeavor on the topic in the country [7, 8, 13, 18], this study boasts the largest sample and is the first to encompass dentists from all geographic regions of Brazil. Building upon preceding data, this study identifies a satisfactory level of knowledge yet significant gaps in training, particularly regarding certain technical aspects of oral cancer. Another remarkable result was that dentists with fewer years since graduation perceived themselves as more prepared to perform oral cancer diagnoses as had been shown in a previous study [18].

Regarding recognizing disease risk factors, preferred oral sites, and the most frequent tumor types, a relatively sound level of knowledge is evident. However, from a practical standpoint, these professionals display limited training, which seems to account for their sense of inadequacy in carrying out necessary diagnostic procedures. Conversely, the results herein underscore a substantial interest in pursuing continuous education courses related to oral cancer.

Prior investigations involving dentists from other countries generally reveal their knowledge to range from fair to poor [14,15,16, 23]. On the other hand, it appears consensual that professionals actively seeking updates in the field exhibit commendable knowledge of oral cancer [1, 3, 12, 17].

Biopsy is a pivotal procedure in the context of oral cancer diagnosis. In this vein, it is noteworthy that over half of the study participants reported never having performed this procedure (54.5%). A study among Brazilian professionals conducted by Leão et al. [8] indicated that 62% had encountered at least one potentially oral cancer case in their professional life, 83.7% opted to refer suspicious cases to secondary healthcare services, and merely 25% conducted biopsies. Warnakulasuriya and Johnson [22] report that only 21% of professionals perform biopsies after detecting potentially malignant lesions. Braun et al. [2] highlighted a lack of confidence in assessing mouth lesions and conducting biopsies as a key reason for the non-performance of the procedure. These findings are corroborated by our study, as while 65.7% of dentists perceive themselves as well-informed about the clinical appearance of oral cancer, only 45.5% have ever performed a biopsy. Although this number remains low, it is more optimistic than observed in a prior study, which reported that only 25% of dentists had performed biopsies in their professional careers [19].

The rationale behind this might be linked to a lack of practical experience during their undergraduate studies involving observing, examining, and treating patients with oral lesions, or even a lack of interest in delving deeper into the subject [2, 19]. Of the participating dentists in this study, 64.5% affirmed that they believed they had not received sufficient training for conducting oral cancer examinations during their undergraduate education. A recent study by Strey et al. [19] demonstrated that 72.4% of dentists in the public sector reported receiving inadequate clinical training during their undergraduate years. This uncertainty due to insufficient training time for this procedure aligns with what was previously observed in earlier studies [12, 16].

Regarding professionals’ counseling abilities in terms of cessation of risk factors such as smoking and alcohol consumption, there is an evident lack of confidence among dentists in performing this activity [9]. In our study, 75.3% of respondents felt they had sufficient knowledge on the subject, and 74.8% of these professionals believed their patients lacked awareness about preventive and diagnostic aspects of oral cancer, corroborating the earlier presented study. These results suggest a fragile professional-patient relationship, as professionals struggle to impart this knowledge and motivate patients to change detrimental habits that are risk factors for oral cancer.

Braun et al. [2] affirm that engagement in continuous education activities can influence the frequency of detecting oral mucosa lesions, as 88.9% of dentists who identify such lesions most frequently are those attending continuous education activities on oral cancer regularly. A cumulative 62.1% of professionals responding to our questionnaire had taken updated courses within 6 months to 1 year before our study. It is also notable that the majority of these participants (98.5%) expressed a desire for more information or education on oral cancer, reinforcing the interest of professionals participating in this survey in constantly updating themselves on the subject.

Dentists exposed to educational interventions statistically exhibit a significant improvement in their knowledge level [17]. Collela et al. [3] demonstrated knowledge enhancement among professionals who had engaged in continuous education activities on oral cancer in the 12 months before their study. This is crucial, as according to Razavi et al. [16], lack of knowledge stands as the primary barrier to routine oral cancer screenings.

A limitation to be acknowledged in this present study pertains to its sample. The group of dentists enrolled in the TelessaúdeRS-UFRGS platform constitutes a segment of professionals constantly seeking updates. Consequently, the results concerning cancer knowledge might be inflated relative to the reality faced by dentists across Brazil.

The findings of this study demonstrate that Brazilian dentists seem to possess a reasonable understanding of oral cancer. Nevertheless, these professionals feel uncertain about some stages in the process of evaluating oral diseases, which are crucial for the early diagnosis of oral cancer. Thus, it is imperative to implement continuous education initiatives aimed at keeping professionals updated and fostering their preparedness to confront this disease.