title: Assessing the evidence-base and implementation factors associated with early detection /screening of oral cavity cancer in the primary care dental setting
Creators: name: Al Bulushi, Naeema
Publisher: name: University of Glasgow
Year: 2021
Subjects: subject: Oral cavity cancer, mouth cancer, screening, early detection, primary care dental settings.

description: Oral cavity cancer (OCC) is a public health problem, with approximately 355,000 new cases and over 177,000 deaths occurring globally per year. In comparison with many other cancers, 5-year survival rates for OCC are relatively poor and there has been limited improvement in these rates over the past few decades. Delay from first symptom to referral for diagnosis is a risk factor for advanced stage presentation and subsequent poorer survival. By contrast, the treatment of small, early-stage lesions is associated with reduced morbidity and mortality. The oral cavity has been described as a site which is relatively easy to examine, and it has therefore been proposed that improvement in outcomes should be possible through implementation of guidelines associated with the examination of the mouth and surrounding tissues for oral cancer and oral potentially malignant disorders (OPMDs), this process is described as a conventional oral examination (COE). An initial review of the literature showed that although there have been a number of systematic reviews and numerous clinical guidelines on the topic of the COE, there has been limited consistency and insufficient evidence available to support clear practice. Uncertainties remain around a number of factors associated with the examination process including: a) the method of conducting the COE, b) the target population, i.e. high risk or universal approach, c) the frequency of the oral cancer examination procedure, and d) the extent to which adjunct tools are used. Additionally, there is some ambiguity and limited information available on the clinical practice and views of oral health care professionals (OHCPs) and patients around these issues and the barriers and facilitators to implementing the COE in the primary dental care setting. This thesis describes three studies which were undertaken to try and address the identified gaps in the knowledge and evidence base. The first study was a systematic overview of systematic reviews and published clinical guidelines and aimed to identify best practice in relation to oral cavity cancer early detection/ screening. The themes explored were based on the four factors associated with the examination process which were outlined above. The findings were used to develop the subsequent two studies. The second study explored the findings of the systematic overview among OHCPs in dental primary care in Scotland and the Sultanate of Oman (the home country of the author of this thesis). Qualitative in-depth interviews were undertaken with the dental professionals to investigate current practice in relation to the COE process and to identify barriers and facilitators to implementation. Analysis was performed using an up-to-date model of behaviour change – the Behaviour Change Wheel. The interviews also asked for views on the development of risk-based tools to facilitate the prevention and early detection of OCC. The third study was a qualitative survey of dental primary care patients from the two countries to explore their perceptions of the barriers and facilitators to a COE and to obtain their views on the acceptability of risk-based interventions. The systematic overview found that while there was a lack of evidence per se on the effectiveness of opportunistic screening, the conclusions of the high quality systematic reviews and clinical guidelines broadly advocated this approach. The high quality systematic reviews tended to suggest that the COE was more effective in high prevalence populations and also when performed in high risk individuals (defined as those who use tobacco and consume alcohol). However, there was insufficient evidence to support only conducting a COE, or doing so in a more detailed and focused way, in high risk dental patients. There was limited evidence, but some clinical guideline support for a risk-based recall interval for conducting a COE, based on assessed oral cavity cancer risks (3-6 months for patients at high risk, and 1-2 years for those at low risk). There was no evidence for the effectiveness or role of adjunct technologies to support the COE in dental primary care for the early detection / screening of oral cavity cancer. The qualitative studies found that COEs were generally performed by oral health care professionals during dental check-ups, although patients were often not aware of this procedure or that it was undertaken for early detection / screening of oral cavity cancer. There were some variations in clinical practice with regard to how COEs were performed in both Oman and Scotland and also on whether a general or targeted approach was adopted. Most OHCPs used a universal approach, while some targeted - based on age and behavioural risk factors. This perhaps reflects the inconclusive results of the systematic overview in this area. The frequency of patient recall was generally reported to be every six months in both countries, and this is broadly in agreement with the evidence base, although some guidance supports a risk-based approach. While some OHCPs supported more frequent recalls for higher risk patients, there was some reluctance to increasing the time between visits as it was perceived that low-risk patients might not receive optimal care. Many of the dental professionals considered a risk-prediction tool worthy of further exploration, but some concerns were expressed about feasibility, particularly in relation to resource issues. In general, patients indicated they would consider attending more frequently (3-6 months) if identified as being in a high risk group. However, they were somewhat more reluctant to agree to attend less often if they were identified at low risk. Dental patients interviewed seemed, in general, to be happy to be assessed for their oral cancer risk. While the OHCPs were concerned about using the term “oral cancer”, many patients, particularly those in Scotland, did not seem to have a problem with it. Adjunct methods were not used by the OHCPs. However, rather than this practice always being based on knowledge of the evidence base, other barriers were also cited. In Oman this was reported to be due in part to a lack of availability of the technologies, while some in Scotland mentioned time and resource constraints. Some other differences in OHCP responses were found between the two countries, for example – restrictions in social opportunities to conduct a COE in Oman and variations in the reported barriers to the COE (lack of guidance and training in Oman, and time and remuneration issues in Scotland). The commonalities and differences in identified barriers and facilitators between Oman and Scotland indicate opportunities to support implementation of best practice, elicited from the systematic overview, at both clinical and policy levels. Furthermore, research opportunities have been identified, for example, related to the development of a risk assessment tool to support the prevention and early detection of OCC in dental primary care. Such theory-based interventions at the clinical, policy and research levels have the potential for future impact on the morbidity and mortality from oral cancer in the community.