Knowledge and perceptions regarding oral and pharyngeal carcinoma among adult dental patients
Dr Jae Park
School of Medicine
The University of Notre Dame
PO Box 1225
Fremantle WA 6959
Background: The aim of this study was to assess awareness and knowledge of oral and pharyngeal carcinoma and risk perception for developing the cancer among adult patients attending a major dental centre in Perth. Influence of socio-demographic factors on awareness, knowledge and perception was ascertained.
Methods: A random sample of 120 potential participants over the age of 18 who attended the Oral Health Centre of Western Australia between 14 and 18 June 2010 were invited to participate in the survey. A total of 100 participants completed a face-to-face interview guided by a questionnaire.
Results: Seventy-two per cent of the participants had heard of oral and pharyngeal carcinoma. Sixteen per cent knew that both smoking and drinking increased the risk of oral and pharyngeal carcinoma and 49% knew at least one sign or symptom of the cancer. Language spoken at home, education, and employment influenced cancer awareness and knowledge. Sixty-two per cent of the participants considered themselves not at risk of developing the cancer.
Conclusions: The findings suggest that knowledge concerning oral and pharyngeal carcinoma in the community may be limited and educational strategies may be required to improve such knowledge.
Abbreviations and acronyms:
Oral Health Centre of Western Australia
oral and pharyngeal carcinoma
Oral and pharyngeal carcinoma (OPC) is an important global health problem. OPC is the sixth most common cancer worldwide.1 The incidence of OPC is particularly high in India where it is the most common cancer.2 In Australia, OPC makes up 2–3% of all cancers.3–8 An increase of between 23% to 28% in the incidence of OPC over the period 2002–2011 is projected.9 The cancer has a strong association with smoking and alcohol use.10–12 The relative risk of OPC increases by between 10- and 15-fold in smokers.12 Risks increase up to the level of 35 cigarettes per day with no further increases at higher levels of cigarette use.10 The synergistic effect of cigarette and alcohol use on development of OPC is well documented.13
Overseas studies have suggested that the public is not well aware of risk factors associated with OPC and that the level of knowledge is influenced by socio-demographic factors.14–16 One study has also suggested that people are more aware of the association of tobacco use with OPC than that of alcohol consumption with the cancer.15 In contrast, evidence suggests that the general public is well aware of the associations between smoking and lung cancer, and between drinking and liver cirrhosis.16
The prognosis for OPC is poor, with an overall five-year survival rate of 59%.17 Mortality rates depend on cancer stage, varying between 30% and 81%.17 Early cancer detection improves survival.
Despite the increasing incidence and high mortality rates of OPC, there is a dearth of literature regarding knowledge of the cancer in the Australian community. The aim of this study was to assess awareness and knowledge of OPC and OPC risk perception among adult patients attending a large public dental centre in Perth. Influence of socio-demographic factors on awareness, knowledge and perception was ascertained.
Materials and methods
Sample and setting
The Oral Health Centre of Western Australia (OHCWA) is the only institution that provides tertiary teaching in dentistry in Western Australia. It provides specialist and general dental services to public as well as private dental patients. Based on the results of a British study,14 a sample size of 100 subjects was determined appropriate to obtain an absolute precision of 10%. Participants were limited to those 18 years of age or over who understood the purpose of the study and were able to give written consent after reading the information sheet and being informed verbally about the study.
Data were collected by conducting face-to-face interviews guided by a predetermined questionnaire. All interviews were conducted by the principal investigator after explaining the purpose of the study, answering questions regarding the study and obtaining written consent. One hundred participants were recruited from patients waiting for appointments with third, fourth and fifth year dental students. To reduce selection bias, 20 consecutive patients who arrived at the clinic from 10 am to 12 pm in the period between 14 and 18 June 2010 were asked to participate. Data were collected until target numbers were reached.
A literature review of previous studies concerning risk factors, signs and symptoms, and risk perceptions identified potential items for the survey instrument.14–16 The survey instrument comprised 21 items assessing the participants’ awareness of OPC, knowledge of risk factors, signs and symptoms of the cancer and perceived risk of developing OPC in their lifetime. Socio-demographic information such as age, gender, educational level and history of alcohol and tobacco use was also collected.
Awareness of OPC was ascertained by asking the following question: ‘Have you ever heard of mouth and throat cancers?’. Response categories for the question were ‘yes’ and ‘no’. Awareness of OPC was compared to that of lung cancer and a question regarding the source of information was asked. Knowledge of OPC risk factors, signs and symptoms was assessed with open-ended questions (Table 1). Knowledge of risk factors for lung cancer was ascertained for comparison with that of OPC risk factors. A question about perceived risk of developing OPC was asked: ‘Would you consider yourself at risk of developing mouth and/or throat cancer(s) in your lifetime?’. Response categories for the question were ‘yes’ and ‘no’.
Table 1. Questions to assess knowledge of oral and pharyngeal carcinoma risk factors, signs and symptoms included in the questionnaire
|OPC risk factors||What causes mouth and throat cancers?|
|OPC signs and symptoms||What are signs or symptoms of mouth and throat cancers?|
The survey included questions about lifetime and current tobacco use, and current level of alcohol use. The CAGE questions (1. Have you ever felt you needed to cut down on your drinking? 2. Have people annoyed you by criticizing your drinking? 3. Have you ever felt guilty about drinking? 4. Have you ever felt you needed a drink first thing in the morning to steady your nerves or to get rid of a hangover?) were used to assess alcohol dependence.18 A total score was constructed by adding all of the ‘yes’ responses. Subjects who had a score of 2 or greater were deemed to have had a likelihood of a history of alcohol dependence. The CAGE questionnaire carries a sensitivity of 75% and specificity of 96% in identifying alcohol dependence.18
Statistical analyses were performed using SPSS for Windows version 16 (SPSS Inc., Chicago, IL, USA). In all models, the following variables were included: age, gender, country of birth, language spoken at home, Aboriginality, education level, employment, occupation, last visit to dentist, last visit to doctor, alcohol and smoking history. Chi-squared tests were used to assess the presence of an association between outcomes of interest and socio-demographic factors. Univariate analysis of variance was used to determine the influence of each variable on the outcomes of interest. Multivariate logistic regression models were performed to identify the independence of the effects from other variables and conducted in order to determine significant independent predictors of the outcomes of interest. A probability value of less than 0.05 was considered statistically significant in both univariate and multivariate analyses.
Ethical approval was obtained from the Human Research Ethics Committee, The University of Notre Dame, Western Australia.
A total of 120 patients were invited to participate and 20 declined. Respondents declined due to lack of interest (n = 9), non-possession of reading glasses (n = 4), or other miscellaneous reasons (n = 7). Forty-seven per cent of participants (n = 47) were male. Fifty per cent were either ex-smokers (n = 36) or current smokers (n = 14), and 42% had a smoking history of more than 10 years (n = 42). Seventy-one per cent of participants were drinkers (n = 71). The socio-demographic characteristics of participants are shown in Table 2.
Table 2. Socio-demographic characteristics of participants (n = 100)
|Country of birth||Australia||47||47.0|
|Language spoken at home||English||83||83.0|
|Education level||<Year 10||21||21.0|
|Trades and related||2||8.0|
|Clerical, sales and services||12||48.0|
|Production and transport||3||12.0|
|Labourers and related||2||8.0|
|Smoking history||Never smoked||50||50.0|
|Smoking duration in years‡||0–5||1||2.0|
|Drinking history||Never consumed alcohol||17||17.0|
|Quit drinking alcohol||12||12.0|
|Currently drink alcohol||71||71.0|
|Amount of alcohol consumption (standard drinks/week)§||1–10||58||81.7|
|Last visit to doctor||<6 months||89||89.0|
|>6 months, <12 months||4||4.0|
|Last visit to dentist||<6 months||59||59.0|
|>6 months, <12 months||19||19.0|
Awareness of OPC
Seventy-two per cent of participants had heard of OPC. In contrast, all participants had heard of lung cancer. Three per cent of participants had heard of OPC through their dentist whereas 26% had heard of the cancer via television and radio media (Table 3). Language spoken at home and employment influenced participants’ cancer awareness. In the univariate logistic regression analysis, participants who spoke English at home were three times more likely to have heard of OPC (p = 0.043) than those who did not speak English at home. Participants who were employed were five times more likely to have heard of OPC than those who were unemployed (p = 0.036). In the final logistic regression model, there was no independent predictor of awareness of OPC.
Table 3. Sources where participants had heard of oral and pharyngeal carcinoma
|Previous oral and pharyngeal cancer||1||1.0|
Knowledge of risk factors for OPC
Sixty-three per cent of participants could identify at least one correct risk factor for OPC. However, only 16% could identify both smoking and drinking as risk factors for OPC (Table 4). In comparison, all participants could identify at least one correct risk factor for lung cancer (Table 5). For the statistical analysis, the outcome was dichotomized into zero (doesn’t know any correct risk factor for OPC) and 1 (knows at least one correct risk factor for OPC). Socio-demographic factors that had statistically significant interactions with the participants’ knowledge of risk factors for OPC were: (1) language spoken at home (participants who spoke English at home were three times more likely to know at least one correct risk factor for OPC than those who did not speak English at home (p = 0.017)); (2) education (those who had university degrees were seven times more likely to know at least one correct risk factor compared to those with less than Year 10 education (p = 0.004)); and (3) employment (those who were employed were four times more likely to know at least one correct risk factor than those who were unemployed (p = 0.010)).
Table 4. Participants’ knowledge of risk factors for oral and pharyngeal carcinoma
|Smoking, drinking and/or other correct risk factors||16||16.0|
Table 5. Participants’ knowledge of risk factors for lung cancer
|Smoking and at least one other cause (e.g. asbestos exposure)||16||16%|
Higher education level (OR, 11.29; 95% CI, 1.21–21.52) and being employed (OR, 20.58; 95% CI, 2.91–31.47) were independent predictors of knowing risk factors for OPC in the final logistic regression analysis (Table 6).
Table 6. Multivariate logistic regression model for risk factors for oral and pharyngeal carcinoma
|Less than Year 10 (Reference)|
| Year 10||2.61||0.34–7.33||0.32|
| Year 12||8.73||0.59–81.07||0.35|
| University degree||11.29||1.21–21.52||0.03|
Signs and symptoms of OPC
Fifty-one per cent of participants did not know any correct signs or symptoms of OPC (Table 7). Non-healing mouth ulcer, bleeding gums, growth in the mouth and lump in the neck were commonly identified correct signs or symptoms of OPC (Table 8). Some of the incorrectly identified signs or symptoms of OPC were recurrent dental abscesses, black tongue and dental caries (Table 8). Language spoken at home and education influenced participants’ knowledge of signs or symptom of OPC. Participants who spoke English at home were almost four times more likely to know at least one correct sign or symptom of the cancer than those who did not speak English at home (p = 0.028). Participants who had university degrees were almost five times more likely to know at least one correct sign or symptom of the cancer than those with less than Year 10 education (p = 0.021). In the final regression analysis, higher education level was the only independent predictor of knowing at least one correct sign or symptom of OPC (OR, 6.77; 95% CI, 3.99–41.61) (Table 9).
Table 7. Participants’ knowledge of correct signs or symptoms of oral and pharyngeal carcinoma
|Four or more||5||5.0|
Table 8. Signs or symptoms of oral and pharyngeal carcinoma mentioned by participants
|Non-healing mouth ulcer||23|
|Growth in mouth||13|
|Lump in the neck||13|
|Pain on swallowing||6|
|Change in voice||6|
|Recurrent dental abscesses (incorrect)||12|
|Black tongue (incorrect)||9|
|Dental caries (incorrect)||7|
Table 9. Multivariate logistic regression model for signs and symptoms of oral and pharyngeal carcinoma
| Less than Year 10 (Reference)|
| Year 10||0.52||0.19–3.02||0.47|
| Year 12||0.39||0.13–1.83||0.23|
| University degree||6.77||3.99–41.61||0.04|
Perceived risk of developing OPC
Thirty-eight per cent of participants perceived themselves at risk of developing OPC in their lifetime. Current smokers were six times more likely to perceive themselves at risk of developing the cancer than those who had never smoked (p = 0.005). Those who were unemployed were four times more likely to perceive themselves at risk of developing the cancer than those who were employed (p = 0.007). The final regression model showed that education was the only independent predictor of cancer risk perception. Perceived cancer risk decreased with the increase in education level (OR, 0.16; 95% CI, 0.02–0.96) (Table 10).
Table 10. Multivariate logistic regression model for cancer risk perception
| Less than Year 10 (Reference)|
| Year 10||0.57||0.11–3.52||0.54|
| Year 12||0.29||0.19–1.47||0.14|
| University degree||0.16||0.02–0.96||0.04|
This study demonstrated the general lack of knowledge regarding OPC among the participants. Seventy-two per cent of participants were aware of OPC compared with all participants being aware of lung cancer. The majority of participants had heard of the cancer via television and radio media. Doctors and dentists appeared to play little role in educating patients about OPC. Only 12% of participants had heard of the cancer through their doctor or dentist. Fifty-eight per cent of participants identified smoking as a risk factor for OPC. However, only 21% could identify alcohol consumption as a risk factor for OPC. The study found that socio-demographic factors affected participants’ level of knowledge regarding OPC. Speaking English at home, being employed and educated had positive influences on the cancer awareness and knowledge. Other socio-demographic factors such as age, gender, country of birth, and alcohol and smoking history did not appear to exert any influence on the knowledge of OPC. Participants who were current smokers and unemployed were more likely to perceive themselves at risk of developing OPC in their lifetime.
The results of this study reflect previous studies by Horowitz et al.15 and Warnakulasuriya et al.14 which found that awareness of OPC was lower than that of other cancers and life-limiting illnesses caused by tobacco and alcohol use. Also, according to these studies, knowledge of drinking as a risk factor for OPC was significantly lower than that of smoking as a risk factor for the cancer.
There has been an increasing emphasis on informing the public of the association between smoking and OPC through the media, evidenced by the recent ‘Make Smoking History’ advertising campaign. An Australian study showed that this media campaign against smoking had a positive impact on cessation of smoking.19 Our study supports the effectiveness of this campaign as it was where almost 50% of participants gained OPC awareness. Comparatively, few attempts at informing the public of the harmful effects of alcohol abuse have been made in Australia. However, an overseas campaign appeared to be successful in increasing awareness of safe alcohol consumption among the public.20 A study by Harris et al.21 showed that a majority of heavy alcohol consumers were also tobacco smokers. It has been estimated that OPC in tobacco and alcohol users develop 15 years earlier than in those who do not smoke or drink.13 A focus on informing the public of the substantial increase in OPC risk with the use of both tobacco and alcohol is needed and informing the public through the media appears to be effective.
A questionnaire-based survey of UK dentists has shown that few dentists routinely inquire about the smoking habits of their patients.22 Continual education available for dentists and other health providers on various aspects of OPC may translate to an increase in patients’ knowledge regarding OPC.
The Health Belief Model explains, predicts, and influences individual’s health related behaviours.23 The model can also be used as the frame of reference for initiating health promotion dialogue with patients. According to the model, an awareness of susceptibility to illness is an important factor in the induction of health behaviour changes. The fact that those with risk factors for OPC perceived themselves at risk of developing the cancer in our study indicates that readily available information regarding the cancer can increase awareness and knowledge of the cancer and result in behavioural modifications and early presentation to health providers.
Based on the results of the study, there is a clear need to increase public awareness of risk factors, and signs and symptoms of OPC. Those identified in this study as less knowledgeable regarding OPC need to be targeted to increase their awareness and knowledge of the cancer.
In conclusion, we investigated awareness and knowledge of OPC among adult dental patients attending OHCWA for dental treatment and found deficits in their knowledge of signs, symptoms and risk factors for the cancer. The level of knowledge was influenced by socio-demographic factors. Cancer risk perception was higher among participants who were unemployed and current smokers. Both professional efforts and public education in improving awareness and knowledge of OPC risk factors, signs and symptoms are clearly needed.
The authors are grateful to Professor Kathryn Hird for her guidance in the design of the research.