Smoking

Smoking is an independent risk factor for head and neck cancer.Reference Maasland, van den Brandt, Kremer, Goldbohm and Schouten ¹ Patients who continue to smoke during radiotherapy are more likely to develop osteoradionecrosis and to require hospitalisation during treatment. Continued smoking through radiotherapy was thought to have an adverse effect on local control (hazard ratio 1.5) and survival (hazard ratio 1.7), but more recent evidence would suggest baseline smoking status is more important.Reference Zevallos, Mallen, Lam, Karam-Hage, Blalock and Wetter ² Smoking cessation before surgery is desirable to reduce the risk of anaesthetic related complications and improve wound healing, particularly after reconstructive surgery.Reference Tang, Oakley, Dale, Purushotham, Moller and Gallagher ^{3 , 4}

Quitting tobacco smoking for a short period of time (one to four years) results in a head and neck cancer risk reduction of about 30 per cent compared with current smoking, reduces the risk of laryngeal cancer by 60 per cent after 10–15 years and after 20 years can reduce the risk of developing oral cavity cancer to the level of a never smoker.Reference Marron, Boffetta, Zhang, Zaridze, Wunsch-Filho and Winn ⁵

Alcohol

Alcohol is the other major independent risk factor for head and neck cancer. Patients who continue to drink heavily after treatment for head and neck cancer have a significantly worse quality of lifeReference Potash, Karnell, Christensen, Vander Weg and Funk ⁶ and continued drinking has a negative impact on survival (hazard ratio 1.28).Reference Mayne, Cartmel, Kirsh and Goodwin ^{7 ,} Reference Fortin, Wang and Vigneault ⁸ The beneficial effects of quitting alcohol, on the risk of developing head and neck cancer, are only observed after more than 20 years, when the level of risk reaches that of non-drinkers.Reference Marron, Boffetta, Zhang, Zaridze, Wunsch-Filho and Winn ⁵

Cessation of alcohol on admission for surgery can present a significant problem in heavy drinkers. A review in the British Medical Journal suggests that we should screen all patients for excessive alcohol consumption with a validated questionnaire such as Fast Alcohol Screening Test.Reference Parker, Marshall and Ball ⁹

Human papilloma virus

Human papilloma virus -16 is an increasingly relevant causative agent in oropharyngeal and oral squamous cell carcinoma (SCC), however doubt remains in other sites and for other HPV subtypes. Combined data from recently published (2006–2009) studies shows that 55 per cent of 654 oropharyngeal SCC cases were HPV-16 positive.Reference Mehanna, Beech, Nicholson, El-Hariry, McConkey and Paleri ¹⁰ The prevalence of HPV-16 chronic infection in oropharyngeal mucosa of the general population is currently unclear. Without a clinically identifiable premalignant lesion, any future (primary or secondary) screening approach would rely on molecular biomarkers. Oral HPV infection increases with numbers of recent oral sex partners and isolated cases of transmission of HPV-16 between partners leading to the possible ‘transmission’ of cancer have been reported.Reference D'Souza, Kreimer, Viscidi, Pawlita, Fakhry and Koch ¹¹ Evidence seems currently insufficient to counsel avoidance of specific sexual activities, over and above guidance that informs the prevention of other sexually transmitted diseases. It is awaited with interest as to whether the current programme of vaccination against high risk HPV (strains 16 and 18) offered to 12–13-year-old girls will in the future reduce the incidence of head and neck squamous cell carcinoma (HNSCC).

Premalignant lesions

Leukoplakia and erythroplakia are common premalignant lesions; however, most HNSCC cases have no history of such antecedent lesions. Biopsy-proven epithelial dysplasia is demonstrated in 25 per cent of biopsies of leukoplakia but most erythroplakia; however, HPV-16 is very rarely a factor in these conditions. The significant clinical predictors of malignant transformation in oral dysplastic lesions are non-smoking status, sub-site (e.g., high risk in lateral tongue and low risk in floor of mouth), non-homogeneous appearance, size of lesion greater than 200 mm and higher histological grade (severe vs mild/moderate). A recent systematic review of oral dysplasia (992 patients) showed malignant transformation in 12.1 per cent after mean 4.3 years following biopsy.Reference Mehanna, Rattay, Smith and McConkey ¹² Severity of dysplasia predicted for malignant transformation (p = 0.008). Lesions that were not excised demonstrated considerably higher transformation rate than those that were excised (p = 0.003).Reference Ho, Field, Field, Risk, Rajlawat and Rogers ¹³ A binary histological grading into the high and low risks has been suggested based on good predictive power that has been independently verified in other series. A systematic review of laryngeal dysplastic lesions (942 patients) showed transformation in 14 per cent after a mean interval of 5.8 years, again severity of dysplasia correlated with risk of transformation.Reference Weller, Nankivell, McConkey, Paleri and Mehanna ¹⁴

Importantly, these data only reflect patients already referred for a specialist opinion and with biopsy-proven dysplasia. In population-based studies of oral leukoplakia without histological inclusion criteria the risks are much lower; 40–50 per cent regress spontaneously and less than 1 per cent transform.Reference Roosaar, Yin, Johansson, Sandborgh-Englund, Nyren and Axell ^{15 ,} Reference Lodi, Sardella, Bez, Demarosi and Carrassi ¹⁶ There is insufficient evidence to justify screening in the general population to prevent oral cancer.Reference Brocklehurst, Kujan, Glenny, Oliver, Sloan and Ogden ¹⁷

The premalignant potential of oral lichen planus (OLP) is controversial; however, rigorously conducted retrospective series have confirmed the risk in classic inflammatory OLP with histological confirmation is low, at about 1 per cent. Oral lichenoid lesions which harbour features of OLP, but also epithelial dysplasia do present a modest risk for malignant transformation, and in some series this subset reflect the only cancer cases arising, interestingly with a predisposition to lateral tongue. Proliferative verrucous leukoplakia is a rare condition presenting with exophytic widespread progressive leukoplakia, somewhat refractory to intervention and with very high (50–80 per cent) transformation rates and hence, poor overall prognosis.

Premalignant conditions