Oral Cancer Knowledge and Screening Practices Among Dental Professionals in Yemen: a Web-Based Survey

Abstract

Background

Good knowledge and screening practices of dental professionals for oral cancer (OC) will inevitably improve its prognosis. The present study sought to evaluate OC knowledge and practices among dental professionals in Yemen.

Methods

This study was conducted among Yemeni dentists. The used tool was a prevalidated online questionnaire composed of items on the knowledge, practices, and barriers of OC screening and early detection. The data were managed and analysed using SPSS Version 28.0.

Results

A total of 506 dental professionals completed the questionnaire. The participants showed moderate levels of knowledge on risk factors and clinical signs of OC. While the majority reported tobacco (89.9%) as a potential risk factor, only 76.7% and 57.5% of the subjects reported a potential role for alcohol consumption and old age. Regarding clinical signs, the majority reported that OC can present as nonhealing ulcer (90.3%) or white/red patch (87.2%), yet only 73.7% reported that it can present as swelling/lump, and around 32% reported that teeth attrition is one of its clinical signs. Concerning practices, most of the participants reported asking their patients about their tobacco habits (84%), routinely examine patients’ oral mucosa (81.4%), and refer suspicious lesions to specialists (91.3%). Only 44.9% reported feeling confident regarding their knowledge and training on OC. Specialists and those who attended educational courses on OC were more knowledgeable, more confident, and showed better practices than their counterparts. Inadequate knowledge/training, lack of time, and lack of financial compensation were the most reported barriers to OC screening and early detection.

Conclusion

The present study indicates marked gaps in the knowledge and screening practices of OC among Yemeni dentists. Therefore, conducting periodic continuing courses along with interventional trainings are urgently recommended to address these gaps.

Introduction

Oral cancer (OC) represents a critical public health challenge worldwide.¹ The estimated new cases of oral and oropharyngeal cancers in 2019 were 370,000 and 199,000 estimated deaths, representing a high mortality rate of approximately 54%.¹ The overall global 5-year survival rate of OC is the lowest worldwide range in 50%,² which can plummet to as low as 30% in low-resource settings, mostly due to late-stage diagnosis.^3,4 Typically, the estimated incidence and mortality rates of OC are higher in developing and underdeveloped countries compared to developed ones.⁵ The disability-adjusted life years lost due to OC are also substantial, reflecting significant health care and societal burdens it entails.⁶ More than 90% of OC cases are predominantly squamous cell carcinomas (SCC).⁷ OC is a multifactorial disease, with tobacco and alcohol consumption are the primary risk factors, synergistically contributing to approximately 75% of OC cases worldwide.⁸ A growing concern is paid to the role of the high-risk human papillomavirus (HPV), particularly HPV-16 and 18, especially among younger populations, linked to approximately 15%-25% of OC.⁹ Other potential factors include genetic predispositions, poor oral hygiene, dietary deficiencies, and sun exposure regarding lip cancer.¹⁰

Basically, cancer is a significant life-threatening illness, particularly in developing countries like Yemen.¹¹ Despite the lack of accurate data on the incidence rates of cancers, data from tertiary cancer centres indicate relatively high rates of OC.¹² On the basis of such data, a systematic review suggested that Yemen has one of the highest OC incidence rates in the Arab world, particularly among young-aged patients,¹³ underscoring the need for further interventions. It is highly expected that the condition has even worsened over the past 10 years owing to the political instability and the ongoing civil war, which would result in unprecedented health and economic consequences.

As a rule of thumb, the earlier the diagnosis, the better the prognosis. In the context of OC, diagnosis at an early stage improves survival rates significantly to over 80%.¹⁴ Recent developments in different fields, such as imaging techniques and the use of biomarkers, herald major positive advancements in early detection protocols.¹⁵ For example, using image processing and artificial intelligence in the early detection of OC has demonstrated superior performance compared to feature-based approaches in medical image analysis, surpassing human specialists in various lesion recognition scenarios.¹⁶ However, human-guided screening remains the gold standard and the most feasible and realistic approach.

Addressing the complex challenges imposed by OC requires a multifaceted approach.^4,17 In the lead, early detection, enhanced public awareness, and robust global health policies are essential to improve outcomes and reducing the burden of this devastating disease.^4,14 Dental professionals, in particular, can play a pivotal role in the prevention and early detection of OC. Their role extends to public education about OC, and the risks associated with tobacco and alcohol use, providing tobacco cessation counselling, routine oral mucosa examination, and referral of suspicious oral mucosal lesions.^18,19 The said routine oral mucosal examination, which is a simple and not time-consuming procedure involving visual and tactile assessment, and tissue biopsy, when necessary, are the primary methods currently used to detect OC and its precursor conditions.¹⁴ However, due to the clinical heterogeneity and subtle nature of OC signs and symptoms, general dentists may struggle to differentiate it from benign conditions like benign ulcers and/or white/red lesions.¹⁶

For dental professionals to efficiently contribute to the early diagnosis and prevention of OC, they should have adequate knowledge, clinical training, and motivation. Unfortunately, several studies worldwide reported inadequate knowledge among dental professionals, and highlighted the urgent need for enhancing knowledge and screening skills regarding the prevention and detection of OC.^18,20, 21, 22, 23, 24 Despite the high prevalence of OC and its risk factors in Yemen, there is a scarcity in published data concerning the knowledge and practices of OC among Yemeni dental professionals, with only one published study in this regard.²⁵ The latter study included a sample size of 214 Yemeni dental professionals and reported inadequate awareness and practices of OC. Understanding OC knowledge, and practices among dental professionals is of paramount importance to assess the extent to which they will effectively and confidently contribute and engage in the fight against this deadly disease. In the light of scarcity of published data, the current study was undertaken to investigate OC knowledge, practices, and barriers to screening and early detection among dental professionals in Yemen.

Materials and methods

Participants and ethics approval

The present questionnaire-based, cross-sectional study targeted a convenience sample of dental professionals working in private and public sectors. The study was conducted between January and April 2024.

The sample size was calculated using ‘WHO sample size calculator’ based on the following parameters: level of confidence measure = 1.96, margin of error = 0.05, baseline level of the indicators (knowledge) = 0.9, design effect = 1.5, expected response rate = 0.5, and number of age/sex estimates = 1. The obtained sample was 414 participants.

The study's protocol was reviewed and approved by the Ethics Committee, Faculty of Dentistry, University of Science and Technology, Aden, Yemen. Informed consents were obtained from all participants as indicated below.

Study tool and data collection

An online-based questionnaire, prepared as Google Form, was distributed to potential participants via emails and social media means such as WhatsApp groups and Facebook. The said questionnaire was prevalidated and applied in previous studies.^26,27 Furthermore, the questionnaire was pretested on a convenient sample aiming to ensure clarity and ease of completion; minor modifications were done accordingly. The questionnaire is composed of 32 items divided into four main parts (Appendix 1). The first part pertained to the participants’ demographic and professional data including gender, age, qualification/specialty, years since graduation, place of work, and whether the participants attended continuing professional development (CPD) courses or workshops. The second part involved 22 items related to OC general knowledge and its risk factors and clinical signs. The responses to these items were either ‘Yes’, ‘No’, or ‘I Don't Know’. The third section consisted of 6 items addressing OC screening practices, where either ‘Yes’ or ‘No’ were the responses. Finally, an item focused on barriers to screening, allowing participants to choose more than one option.

The questionnaire was prefaced by a cover letter detailing the aim of the study, outlining the research team members, providing instructions for completing the questionnaire, assuring the confidentiality and anonymity of the respondents’ data, and asking to ‘Agree’ or ‘Disagree’ to participate. Only participants who chose ‘Agree’, as an ‘informed consent’, were automatically allowed to finalise the questionnaire. Reminders were sent twice at 10-15-day intervals. To avoid duplicate participation, responses to the questionnaire were made sensitive to the Internet Protocol (IP).

Statistical analysis

The collected data were saved as an excel file from which they were exported into SPSS Version 28.0. Descriptive data were presented as frequencies and percentages, and means and standard deviations, as appropriate. Chi-squared test was used to compare groups for categorical variables while independent t-test was used for numerical variables. To quantify respondents’ overall knowledge and overall practice scores of OC, each correct/positive response was given a score of 1, while incorrect/negative response was given a score of 0. Accordingly, the maximum score for knowledge-based items was 22, while the maximum score for practice-related items was 4. A P value of less than .05 was considered significant.

Results

A total of 506 dental professionals completed the questionnaires. Table 1 presents details on the demographic data of the study participants. Majority of participants are male (57.5%), 20-30 years old (57.1%), general dental practitioners (64.6%), working in private sector (31.6%), graduated less than 5 years ago (64.6%), nonsmokers (81.4%), and reported never attending any continuous educational courses (CPD) on OC (68.4%).

Table 1.

Characterisations of the study subject.

Variables	N	%
Gender
Male	291	57.5
Female	215	42.5
Age
20-30 years	289	57.1
31-40	136	26.9
>40 years	81	16
Specialty
GDP	327	64.6
OMS and allied specialties*	64	12.6
Orthodontists/paedodontists	57	11.3
Other specialties	58	11.5
Setting
Public	39	7.7
Private	160	31.6
Public and private	42	8.3
University	141	27.9
University and private	124	24.5
Graduation time
<5 years	326	64.6
6-10 years	73	14.4
>10 years	107	21.1
Smoking
Yes	94	18.6
No	412	81.4
Attendance CPD on OC
Yes	160	31.6
No	346	68.4

CPD, Continuing professional development; GPD, general dental practitioner; OC, oral cancer.

^⁎Oral and Maxillofacial Surgery, Oral Medicine, Oral Pathology, and Oral Radiology.

Table 2 shows the correct answers to the items on OC knowledge, which ranged from 25.5% to 93.3%. Most participants reported that squamous cell carcinoma was the most common form of OC (87.7%), the tongue and floor of the mouth being the most common sites (84%), and early detection as a key factor in improving prognosis and survival rates (93.5%). However, only 66.6% reported that most OC lesions are preceded by oral potentially malignant disorders, and around one-third of the participants reported that most OC lesions are diagnosed in the early stages.

Table 2.

Knowledge on oral cancer, its risk factors, and clinical signs among the subjects by gender (% of correct answers).

General knowledge on OC	Correct answer	Total	Male	Female	P value
1. Squamous cell carcinoma is the most common form of oral cancer?	Yes	444 (87.7)	254 (87.3)	190 (88.4)	.224
2. Tongue and floor of the mouth are the most common sites for oral cancer?	Yes	425 (84)	244 (83.8)	181 (84.2)	.658
3. Oral cancers are usually preceded by OPMD?	Yes	337 (66.6)	196 (67.4)	141 (65.6)	.919
4. Most of oral cancer lesions are diagnosed in early stages?	No	337 (66.6)	205 (70.4)	132 (61.4)	.034
5. Early detection of oral cancer can improve the prognosis and survival rate?	Yes	473 (93.5)	276 (94.8)	197 (91.6)	.308
6. Most of oral cancers occur in young adults?	No	257 (50.8)	152 (52.2)	105 (48.8)	.046
Risk factors
7. Tobacco use?	Yes	455 (89.9)	263 (90.4)	192 (89.3)	.649
8. Alcohol consumption?	Yes	388 (76.7)	225 (77.3)	163 (75.8)	.753
9. Khat chewing?	No	129 (25.5)	70 (24.1)	59 (27.4)	.591
10. Sun exposure for lip cancer?	Yes	375 (74.1)	216 (74.2)	159 (74)	.977
11. Denture wearing?	No	194 (38.3)	113 (38.8)	81 (37.7)	.729
12. Soft diet?	No	385 (76.1)	213 (73.2)	172 (40.5)	.150
13. Advanced age?	Yes	291 (57.5)	182 (62.5)	109 (50.7)	.016
14. Vegetables-rich diet?	No	402 (79.4)	232 (79.7)	170 (79.1)	.705
Clinical signs
15. Nonhealing ulcer?	Yes	457 (90.3)	263 (90.4)	194 (90.2)	1
16. Red or white patch?	Yes	441 (87.2)	262 (90)	179 (83.3)	.053
17. Swelling/lump?	Yes	373 (73.7)	210 (72.2)	163 (75.8)	.636
18. Teeth attrition	No	346 (68.4)	198 (68)	148 (68.8)	.980

With regard to the risk factors, most of the participants reported tobacco use (89.9%) as a risk factor, but lower proportions of them reported old age (57.5%), alcohol consumption (76.7%), and sun exposure for lip cancer (74.1%) as risk factors. Additionally, more than two-thirds of the participants reported khat chewing and denture wearing as risk factors for OC (Table 2). Concerning the clinical signs, the majority reported nonhealing ulcers (90.3%), red or white patches (87.2%), and swelling/lumps (73.7%) as clinical signs of OC (Table 2).

The practices and confidence of the participants regarding OC prevention and early detection are depicted in Table 3. The majority of the participants reported always asking their patients about their tobacco habits (84%), routinely examining oral mucosa (81.4%), and referring suspicious lesions to specialists (91.3%). However, only 70% reported always screening for OC in high-risk patients. There were some differences between males and females. More males than females reported having had the opportunity to examine patients with suspicious oral lesions (72.9% vs 61.9%, P = .009). The opposite was true for asking patients about their tobacco habits (80.4% vs 88.4%; P = .027). Only 44.9% (53.6% of males and 33% of females; P < .001) reported having adequate knowledge and training on early detection and prevention of OC.

Table 3.

Practice and confidence of dentists regarding oral cancer screening and prevention (n [%] of Yes answers).

Questions	Total	Gender		P value
		M	F
Practices
19. Do you always ask your patients about their tobacco habits?	425 (84)	235 (80.4)	190 (88.4)	.027
20. Do you routinely examine the patients’ oral mucosa?	412 (81.4)	238 (81.8)	174 (80.9)	.818
21. Do you screen the oral mucosa of high-risk patients?	355 (70.2)	209 (71.8)	146 (67.9)	.377
22. Have you had the opportunity to examine patients with a suspicious oral lesion?	345 (68.2)	212 (72.9)	133 (61.9)	.009
23 Do you always refer patients with suspicious oral lesions to the specialist?	462 (91.3)	265 (91.1)	197 (91.6)	0.874
Confidence
24. Do you feel you have sufficient knowledge and training on early detection and prevention of oral cancer?	227 (44.9)	156 (53.6)	71 (33)	<.001

Table 4 presents the overall scores of knowledge and practice on OC according to the different factors. Although the overall knowledge and practice scores of the specialists (13.16 ± 2.74 and 4.07 ± 1.12, respectively) were higher than those of the general practitioners (12.7 ± 2.43 and 3.89 ± 1.07, respectively), the differences were insignificant (P = .056 and .07, respectively). Further, participants who attended CPD on OC were found insignificantly more knowledgeable (13.12 ± 2.44 vs 12.75 ± 2.59; P = .126) but showed significantly better practices (4.25 ± 0.92 vs 3.81 ± 1.14; P = .001) than those who never did so.

Table 4.

Mean and median scores of knowledge and practice by different factors.

Variables	Knowledge scores		Practice scores
	Mean SD	P value	Mean SD	P value
Gender
Male	12.97 ± 2.69	.279	3.98 ± 1.15	.440
Female	12.72 ± 2.35		3.91 ± 1.01
Qualification
GDP	12.7 ± 2.43	.056	3.89 ± 1.07	.076
Specialists	13.16 ± 2.74		4.07 ± 1.12
Graduation
<5 years	12.82 ± 2.58	.700	3.93 ± 1.09	.877
6-10 years	12.78 ± 2.26		3.97 ± 1.05
>10 years	13.05 ± 2.64		3.99 ± 1.13
CPD on OC
Yes	13.12 ± 2.44	.126	4.25 ± 0.92	<.001
No	12.75 ± 2.59		3.81 ± 1.14
Smoking
Yes	12.82 ± 2.26	.851	3.83 ± 1.18	.235
No	12.87 ± 2.61		3.98 ± 1.07

Supplementary Tables 1 to 5 present details on the participants’ responses to knowledge and practice items by different factors including specialty, years since graduation, and previous attendance of CPD. Specialists showed significantly better knowledge about the occurrence of OC in young adults (P = .011) and about the protective effect of a vegetable-rich diet (P = .020) compared to general dental practitioners. Participants who graduated less than 5 years ago had better knowledge about sun exposure as a risk factor for lip cancer (P = .013), while those who graduated more than 10 years ago had better knowledge about teeth attrition as a clinical sign (P = .014). Significantly more specialists reported having had the opportunity to examine patients with suspicious oral lesions compared to general practitioners (P < .001). Specialists and participants who graduated more than 10 years ago feel they have sufficient knowledge and training on early detection and prevention of OC compared to general dentists and recent graduates (P < .001 and P = .004, respectively). Except for knowledge on tobacco use as a risk factor of OC (P = .038), participants who attended CPD on OC were more knowledgeable about the risk factors of OC, showed positive practices, and were more confident in early detection and prevention of OC than those who never attended any CPD.

With regards to perceived barriers to screening and early detection of OC, lack of knowledge (n = 295, 58%) and inadequate training (53.5%) were the most reported barriers followed by lack of time (37.7%), lack of financial compensation (26.7%), and lack of confidence (23.5%; Figure 1).

Fig. 1.

Barriers to performing screening for oral cancer.

Discussion

The present study revealed moderate levels of knowledge and practices regarding OC among Yemeni dental practitioners. Additionally, the specialty and attendance of CPD were identified as positive determinants of better knowledge and practices. The main perceived barriers to screening of OC were inadequate knowledge/training, lack of incentive, and time restraints. However, similar to most survey-based studies,28, 29, 30 the present study has some potential methodological limitations, and thus the results should be read with caution. One important limitation is the relatively small sample size, which basically was a convenient sample, a matter which raises questions regarding generalisability of the results. In addition, the responses are self-reported, and hence, the results might not have reflected the actual knowledge and practices of Yemeni dental practitioners.

The key finding in the present study is the relatively good knowledge regarding considering tobacco as a risk factor for OC. This finding is consistent with our 2014 survey and other previous studies elsewhere.^25,28,31,32 Contrastingly, however, the participants revealed far less knowledge regarding other important and established risk factors including alcohol consumption, sun exposure, concerning lip cancer, and old age. These findings are also consistent with the results of other previous studies elsewhere,^28,31, 32, 33 indicative a marked deficit in knowledge of dental practitioners globally, a matter that underscores the necessity for provisioning CPD to enhance their knowledge. Another surprising result is about considering khat chewing as a risk factor for OC. In fact, khat (Qat) chewing is a deep-rooted habit in Yemen and many East African countries and is associated with many systemic and oral health consequences such as periodontitis, teeth staining, and benign oral keratotic white lesions.34, 35, 36, 37 However, no sound evidence has been available thus far linking khat chewing to OC.³⁸ Identifying the clinical presentation of OC and its precursors is essential for early detection and referral. In the present study, most of the participants showed moderate levels of knowledge on clinical signs of OC, which again emphasises the need for further training and interventional programs focusing on OC risk factors and clinical signs.

Dental professionals are the Trojan horse in the world's battle against OC. They can play a crucial role in prevention and early detection of OC and oral potentially malignant disorders through providing advice on the risk factors (eg, tobacco and alcohol) and screening for OC through examining the oral mucosa.^30,39 It is heartening that over 80% of the participants showed positive practices regarding OC including asking their patients about tobacco habits and routinely performing oral mucosa examination. These results are in line with other studies conducted elsewhere.^{3,20,23,24,28,29,31} However, it is disheartening that only 70% of the participants reported screening for OC in high-risk patients. This finding is consistent with that reported by Ahmed et al. among Sudanese dentists.³¹ High-risk individuals like old adults (above 40 years old), heavy smokers, smokeless tobacco users, and heavy alcohol drinkers should be meticulously examined for any mucosal changes. And, in case of doubts, the affected patients should be referred to specialist for further investigations. Such results reflect low knowledge and inadequate motivation among the respondents, emphasising the urgent need for establishing proper strategies aiming to enhance such knowledge and providing CPD to boost such motivation and improve dentists’ ability to early diagnose OC. This can be achieved through providing periodic continuous educational and motivational programs (eg, workshops and training courses) on OC for all practicing dentists. There is a mounting body of evidence suggesting that educational courses have a significant impact on dentists’ efficiency in early detection of OC and providing tobacco cessation advice.^40,41 Additionally, incorporating more content about the diagnosis and prevention of OC into the undergraduate and postgraduate curricula is highly recommended.

Unsurprisingly, specialists showed much better knowledge and positive practices than general dental practitioners did. This is expected probably due to their exposure to topics on OC during their graduate training and to their exposure to many patients with oral lesions during their clinical practice. This result confirms our previous findings.²⁵ The impact of continuous educational courses and interventional programs on dental professionals’ knowledge and practices is well established.40, 41, 42, 43 The results of the present study revealed that participants who attended CPD on OC were more knowledgeable and showed better practices than those who never did so. This finding emphasises the importance of CPD in shaping dental professionals’ knowledge and motivation, which is reflected positively in their practices. The result also supports previous studies that reported a significant association between CPD attendance and dental professionals’ knowledge and practices regarding OC.^32,44 Regarding gender, it is important to point out that, although the overall scores of knowledge and practice were comparable among males and females (Table 4), there were statistically significant differences in few items. The most striking one was that male participants reported they are more confident than females regarding early detection and prevention of OC. Another striking item noted was that a significantly higher percentage of male participants reported prior exposure to patients with oral suspicious lesions than female participants (72.9% vs 61.9%). This may explain the better confidence reported by male subjects. Indeed, exposure to oral suspicious lesions helps generate confidence and increases knowledge on the clinical signs and diagnostic tools.⁴⁵

Another key finding is that the majority revealed low confidence in early detection and screening of OC, with the majority felt having insufficient knowledge and training. These results corroborate previous studies and provide further evidence on the need of further training for dental practitioners on prevention and early detection of OC.^21,30, 31, 32^,44,46 In fact, inadequate training and knowledge are the two most recognised barriers to dentists’ active involvement in the fight against OC.^30,31,33,46 It is justified to report inadequate knowledge and low confidence regarding the prevention and early detection of OC among undergrad dental students (not dental professionals), exactly as found in our recent study and other similar studies.^26,47,48 The above debate confirms the urgent need for customising CPD on OC. Other perceived barriers to OC screening include lack of time and lack of any financial compensation, findings similar to previous studies in different countries.^20,21,28, 29, 30, 31, 32, 33^,44 Hence, proper strategies are urgently needed to be in place to ease such shortages. In this context, health insurance coverage of dental services including screening of OC must be activated urgently.

In summary, the present findings reveal gaps in the knowledge and practices of dental practitioners regarding the early detection and screening of OC. The results show a positive association between high qualification and CPD attendance and knowledge/practices of OC. These findings confirm the urgent need for periodic CPD and appropriate training interventions.

Conflict of interest

None disclosed.