Oral cancer screening in general practice
Oral cancer screening and awareness has been increasing in both the media and with patients. Many patients attending general practice appointments are aware of the dentist checking for any abnormalities of the oral soft tissues in addition to the hard tissues.
The aim of this article is to outline two aids to screening. Basic undergraduate training does emphasis the importance of general dental practitioners to be alert towards any early sign of malignancy or pre-malignancy (Figure 1).
Oral cancers are the fifth most common malignancy in men and seventh in women (Oral Cancer FDI document 1999; Professor NW Johnson).
Identifying at-risk patients can help with screening. Early detection is a vital factor if treatment is to be successful, improving the five-year survival rate to over 90%. In particular, those who may be at increased risk are patients who:
1. Chew tobacco/betal nut/paan. This is more common in the Middle East, Bangladesh and Indian subcontinent, where a tobacco based mixture is held within the sulcus. This produces a topical effect onto the mucosa, predisposing it to dyplsatic changes
2. Smoke. This has long been recognised as a risk factor in developing malignancy of the mouth lungs and oropharynx
3. Are heavy drinkers. Alcohol consumption is recognised as a risk factor for developing dysplasia, particularly in conjunction with smoking. Together these two factors greatly increase the relative risk. Spirits having the greater concentration of alcohol and pose a greater potential risk
4. Have a poor diet. A lack of the anti-oxidant effects of vitamins A, C and E has been noted as they scavenge the potentially mutagenic free radicals from damaged cells
5. Have had a previous history of malignancy (oral or otherwise)
6. Are over 40 years old
7. Are male. There is a slight gender predisposition. Oral cancer screening programmes are gradually taking place within general practice. The general dental practitioner will be highly conversant in the protocol for rapid two-week referrals for patients presenting with sinister signs.
However, for a screening programme aimed at otherwise healthy patients, it is important to evaluate each individual’s needs when considering how often a patient should be screened and who should fit the criteria.
In addition to the visual screening, there are oral cancer detection kits available. These have been marketed within the dental press and aim to assist the practitioner in early diagnosis. The two detection kits discussed here are Ora-Test and Vizi-Lite, both products available from Zila Pharmeceuticals. These kits are aimed at patients who present with an increased risk factor and can typically be used on an annual basis.
Vizi-Lite is an oral lesion identification and marking system that is used as an adjunct to a conventional head and neck examination. It is comprised of a chemiluminescent light source to improve the identification of lesions and a blue phenothiazine dye (TBlue630) to mark those lesions identified by Vizi-Lite. Patients are advised to rinse with the solution for 30 seconds, gargle and spit out. The oral cavity is then examined and the Vizi-Lite used to help identify any at-risk sites. It is worth noting that the test may appear positive for areas which are traumatised and therefore a second test may be required 14 days after the first.
Ora-Test is a simple mouthwash test is distributed to 14 countries. The test consists of three vials containing a small amount of liquid for the patient to rinse with for 30 seconds, gargle and then spit out. Each vial is clearly labelled with a number one to three to indicate the order. The first bottle contains 1% acetic acid which acts as a cleaning agent. The second bottle contains the toludine chloride blue dye and the third contains a post dye rinse of 1% acetic acid to remove the dye excess and make visual examination easier.
Because of the tongue’s anatomy, the taste buds automatically collect a large amount of the dye, causing the dorsum of the tongue to become densely coloured. The use of toluidine blue has long been established as an aid to early detection of neoplastic change.
A mouth map is provided by the manufacturer. This assists the practitioner in recording their findings. A second positive test would be required for both systems after 10-14 days to allow for any false positive results due to tissue trauma. For this reason, the test is usually promoted as a two-stage test where not all patients need the second part. A swab version of will be released in the near future and is expected to cost 50% less than the three solutions.
Oral cancer screening plays an important part in the early detection of malignancy and thereby improving the prognosis of treatment. Screening aids such as those mentioned will aid the general dental practitioner and support the clinical examination, but are in no way any kind of substitute for a thorough clinical assessment.
The general dental practitioner is in an ideal position to screen patients due to the frequency at which patients attend dental practices.