OPINION ARTICLE
Por que o Autoexame da Boca ainda não é Recomendado para Detecção Precoce de Câncer Bucal e das Alterações Orais Potencialmente Malignas?
¿Por qué aún no se Recomienda el Autoexamen Bucal para la Detección Temprana del Cáncer Bucal y de Trastornos Bucales Potencialmente Malignos?
https://doi.org/10.32635/2176-9745.RBC.2025v71n1.4908
Beatriz Nascimento Monteiro da Silva1; José Alexandre da Rocha Curvelo2; Ruteléia dos Santos Assumpção Barroso3; João Vitor Silveira de Azevedo4; Andreia Cristina de Melo5; Daniel Cohen Goldemberg6
1-5Instituto Nacional de Câncer (INCA), Divisão de Pesquisa Clínica e Desenvolvimento Tecnológico. Rio de Janeiro (RJ), Brasil. E-mails: beatriz.silva@inca.gov.br; jose.curvelo@inca.gov.br; ruteleia.barroso@ensino.inca.gov.br; joao.azevedo.trab@gmail.com; andreia.melo@inca.gov.br. Orcid iD: https://orcid.org/0000-0001-6850-297X; Orcid iD: https://orcid.org/0000-0003-3240-941X; Orcid iD: https://orcid.org/0009-0004-5821-5757; Orcid iD: https://orcid.org/0009-0006-6073-0154; Orcid iD: https://orcid.org/0000-0002-1201-4333
6INCA, Divisão de Pesquisa Clínica e Desenvolvimento Tecnológico. University College London (UCL). London (UK). E-mail: daniel.cohen@inca.gov.br. Orcid iD: https://orcid.org/0000-0002-0089-1910
Corresponding author: Daniel Cohen Goldemberg. Rua André Cavalcante, 37, sala 26 –Centro. Rio de Janeiro (RJ), Brasil. CEP 20231050. E-mail: daniel.cohen@inca.gov.br
INTRODUCTION
Early diagnosis of oral cancer is crucial for favourable prognosis, higher survival rate and improvement of the patients’ quality of life. Because oral cancer is often asymptomatic with various morphologies, identification at early stages is challenging. Oral cancer (OC) can arise from oral potentially malignant disorders (OPMD)1,2, as leukoplakia, erythroplakia, proliferative verrucous leukoplakia, oral lichen planus, lichenoid lesions, oral submucous fibrosis, and when affecting lips vermillion, actinic cheilitis3. In fact, not all OPMD will turn into carcinoma. However, it is undeniable that quite frequently, some of these alterations will undergo malignancy4.
Mouth self-examination has been discussed for years as a possible tool for early detection of OC, although it has never been implemented either by the Brazilian Health System (SUS), the Brazilian Public Health Service, or elsewhere. Previous studies have concluded that mouth self-examination, despite its high specificity, has low sensitivity to detect OPMD, and therefore should not be considered for early diagnosis of these conditions5. However, this hypothesis could be rediscussed if the standardization of methodologies and techniques were universally applied for this practice, and this possibility was the underlying reason of this opinion article.
The importance of self-examination lies in the possibility of detecting these OPMD, both for early diagnosis of lesions that have already transformed, and treatment, which would prevent the malignancy process. This scope reinforces the relevance of oral self-inspection considering that, although an oral squamous cell carcinoma (OSCC), the most frequent OC is not necessarily preceded by an OPMD, an oral mucosa with a clinically normal appearance may have significant potential molecular alterations favoring OSCC development, known as “field cancerization”3.
DEVELOPMENT
Literature findings on the accuracy of self-examination for early diagnosis of OC are conflicting. Chaudhari et al.6, for example, in a study with 2,257 individuals, showed that mouth self-examination is a reliable and effective tool for early detection of OC6. However, in another article with 167,915 individuals, Sankaranarayanan et al.7 concluded that self-examination could reduce 34% of mortality with a real potential to prevent deaths from OC worldwide, although they have only considered individuals with high risk of malignancy7. Inconsistent evidences prevented the Brazilian Ministry of Health to recommend mouth self-examination for early screening of OC and OPMD8.
Walsh et al.9, in an update of a Cochrane systematic review previously published by the same group9, evaluated the diagnosis accuracy of different methods of early detection of OC and OPMD, including oral self-examination10. Four studies with 35,059 individuals as part of a screening program developed in India11, Malaysia12, United Kingdom13 and Brazil14 were selected for their review.
Walsh et al.10 assessed the methodological quality of the studies (using QUADAS-2 tool), which includes four domains: patient selection, index test, reference standard and participant flow and timing. The value of diagnosis accuracy was expressed as sensitivity and specificity. The results revealed that the four studies presented low risk of bias in the patient selection domain. Two of them which only investigated patients with higher risk of OC9 were concerning in relation to the applicability of this same criteria. Furquim et al.14 recruited and assessed only patients with Fanconi’s anaemia and Scott et al.13 selected 45-year old or older smokers.
The same authors10 also judged the risk of bias of the index test (proper mouth self-examination) as uncertain in three studies. In two of them it was not reported whether the self-examination results were interpreted without knowledge of the reference test11,13 and in a third study there was not enough information about the target condition and whether a pre-specified threshold was used. The authors assessed the applicability of the study by Furquim et al. as ‘high concern’14 because the participants were not instructed or trained for mouth self-examination. The other four studies were judged to be of 'low concern’9.
It is worth questioning whether skilled lay people would be able to perform oral self-examination in search of OPMD or OSCC considering that even solidly experienced diagnosticians sometimes do not recognize obvious potentially malignant lesions leading to failure of early diagnosis, which is the primary purpose of this approach.
Only one study presented low risk of bias in the reference standard domain13, mainly because it considered that the reference test must be carried out by a specialist dentist and done before the mouth self-examination properly. Three other studies were judged as ‘uncertain’11,12,14, as there was no information on whether the reference test was interpreted without knowledge of the index test. Regarding the applicability, three studies were of low concern12-14. One study used trained health professionals and was considered as uncertain concern11, since the report states that health professionals’ knowledge was confirmed by a cancer specialist. However, it does not report how this confirmation was carried out. Indeed, Walsh et al.10 point out that the implicit threshold of illness of trained health professionals is different from the one made by an experienced specialist in stomatology10.
Actually, the analysis conducted by Walsh et al.10 related to the flow of patients and the time between tests showed that most of the studies had low risk of bias12-14, except the study by Elango et al.11, which presented a significant number of continuity loss and exclusions of patients without proper compliance11. Overall, they judged that three studies presented uncertain risk of bias12-14, and one study was considered as high risk11.
The applicability concerns were considered high for two studies14,13, uncertain for one study11 and low for the study of Ghani et al.12. Additional evaluations showed that sensitivity was lower than specificity11,12 in two of the four studies, indicating that oral self-examination was not effective in diagnosing OC and consequently should be not recommended. In the other two studies, the sensitivity and specificity values were similar14,13, suggesting that self-examination should be recommended for early diagnosis of OSCC and OPMD. However, both studies were classified as high concern10. Therefore, the authors concluded that heterogeneity caused by different populations, methodologies and analysis presented so far makes evidence related to mouth self-examination indirect, inconsistent, and imprecise. The main discrepancies and inconsistencies can be evaluated in Table 1.
Table 1. Characteristics of the studies evaluated by Walsh et al., 2021
|
Sampling |
Participants (N) |
Index Test (Mouth self-examination) |
Target and Reference |
Characteristic and Proportion Flow |
Observation |
|||||||||
|
Index test
|
Positiveness Description |
Calibration and Training |
Examiners Blindness |
Target Condition |
Reference Standard (RS) |
Positiveness Description |
Calibration Training |
Examiners Blindness |
Received Index test and/or RS |
Received only RS |
||||
|
Elango et al.11 |
≥10yo, from 33 subunits living in two Panchayats, India |
48,080 |
Brochure designed for the population |
White, red, non-healing ulcers, trismus and burn sensation |
Instructions in a specific brochure |
Not described |
Oral Cancer and OPMD |
CHWs recruited from study population |
Presence or absence of OPMD |
One-month training on oral cancer centre |
Not stated |
34,766 were fully evaluated (73.2%) |
Made by CHW |
High prevalence of OPMD and OSCC in the area where participants were recruited and a high rate of missing results since 27% did not conclude their participation in the study |
|
Ghani et al.12 |
Male subjects ≥18 yo |
200 |
After training |
White lesions, red lesions, ulcers, or swellings in their mouth
|
Provided by local dental surgeons who have been calibrated against the specialist
|
Not stated |
Oral mucosal lesions |
Oral medicine specialist |
Presence of oral lesions or abnormalities |
Specialist trained and calibrated in the diagnosis of oral lesions, for oral cancer |
Not stated |
Results of 96 participants. Characteristics not provided |
None |
- |
|
Scott et al.13
|
≥ 45 yo; smoker and recruited by their general dentist practitioner |
53 |
Leaflet made for heavy smokers and drinkers |
Red or white patches, ulcers and swellings |
Following the specific leaflet |
After examination, dentists remain in the room and did not assist self-examination |
White patches, ulcers lumps and swelling |
Dentist examination |
Presence or absence of OPMD |
Not reported |
Reference and index test |
None |
None |
Patients formed a risk group and only 21.8% were fully evaluated |
|
Furquim et al.14 |
≥ 18 yo Fanconi Anemia, bone marrow transplantation high risk of head and neck cancer |
44
|
No training or instruction
|
Not explicitly reported, just presence or absence of abnormalities
|
Verbal instruction with a banner and educational pamphlet
|
Unclear
|
OPMD
|
Clinical examination by a specialist
|
Presence or absence of OPMD
|
Experienced specialist
|
Not stated
|
24.2% were not fully evaluated
|
Made by specialist
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Captions: CHW = community healthcare workers; OPMD = oral potentially malignant disorders; yo = years old.
Due to poor high-quality scientific evidences of the studies to support the use of self-examination for screening programs and surveillance for early diagnosis of OC, its value cannot be validated so far3. Therefore, the need to implement health education for the general population to stimulate the individuals to seek dental care more frequently is mandatory. In addition, the elaboration of booklets, lectures, and education programs to identify scientific references-based risk factors and OPMD seems to be relevant for population awareness about the identification of OC.
On the other hand, it is important to consider the limitations of the study, because, although very relevant, the scope of Walsh’s study is somehow restricted due to the small number of reports included and analysed (n=4)10. This situation leads to false negatives results that cannot be concretely determined as real. The great heterogeneity of the methodologies applied in all studies reveals the weakness of the methodological globality that is necessary for a statistical and reliable verdict on mouth self-examination. However, future methodological consensus may demonstrate that mouth self-examination could be trustable and efficient in public screening. The authors continue to pursue new evidences to evaluate novel methodologies that can circumvent these difficulties to establish a simple and cheap approach to reduce the incidence rates of oral cancer in Brazil.
CONCLUSION
The lack of evidence with high degree of certainty prevents the indication of oral self-examination for screening programs and surveillance of OPMD for the lay population. Health professionals need to remain attentive for signs able to identify both OSCC and OPMD.
As soon as the methodological setbacks that compromise the efficacy of self-examination have been overcome, this methodology may be considered a possible, reliable and an efficient screening strategy, especially for most vulnerable populations intrinsically prone to oral cancer or continuously exposed to traditional risk factors, who sometimes have their diagnosis significantly delayed due to lack of information and access to health services. A systematically assisted oral self-examination approach may be imminent. In these cases, any possibility of early diagnosis can save the patients with OSCC or exponentially improve their quality of life.
CONTRIBUTIONS
Beatriz Nascimento Monteiro da Silva and José Alexandre da Rocha Curvelo contributed to the study design and wording of the manuscript. Ruteléia dos Santos Assumpção Barroso contributed to the acquisition and analysis of the data and critical review. João Vitor Silveira Azevedo contributed to the critical review. Andreia Cristina de Melo contributed to the acquisition and analysis of the data and critical review. Daniel Cohen Goldemberg contributed to the study design, interpretation of the results, wording and critical review. All the authors approved the final version for publication.
DECLARATION OF CONFLICT OF INTERESTS
There is no conflict of interests to declare.
FUNDING SOURCES
None.
REFERENCES
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Recebido em 26/8/2024
Aprovado em 25/11/2024
Scientific-editor: Anke Bergmann. Orcid iD: https://orcid.org/0000-0002-1972-8777
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