From Volume 46, Issue 8, September 2019 | Pages 722-729
Head and neck cancer is a group of cancers that affects the oropharynx, nasopharynx, laryngopharynx and neck. With improving survival rates for patients, general dental practitioners (GDPs) are becoming increasingly likely to engage in the care of affected patients. Therefore, a sound clinical knowledge of the aetiology, treatment and rehabilitation for head and neck cancer is essential for all practitioners who may be involved in the care pathways for such patients.
Head and neck cancer, and the treatment for it, can be one of the most socially disabling conditions and can leave patients with life-changing functional and aesthetic deficits. It is an umbrella term for all cancers in the region, including those of the oropharynx, nasopharynx, laryngopharynx and neck.1
Although oral cancer incidence has risen in recent years (a rise of 30% since the early 1990s),2 treatment modalities have become more successful and survival has improved.3 Therefore, GDPs are becoming increasingly likely to engage in the care pathway of affected patients.
Knowledge of the common risk factors for head and neck cancer can enable dental practitioners to consider the individualized risk levels of their patients and enable them to offer specific and tailored advice. An overview of risk factors for head and neck cancer is outlined in Table 1.
| Environmental | Premalignant Lesions | Inherited Premalignant Conditions | Acquired Immunodeficiency |
|---|---|---|---|
| Smoking | Oral lichen planus | Fanconi anaemia | HIV/AIDS (most commonly Kaposi's sarcoma/non-Hodgkins lymphoma) |
| Alcohol | Leukoplakia and erythroplakia | Ataxia telangiectasia | Poor nutrition |
| HPV-16 | Chronic hyperplastic candidosis | Bloom's syndrome | Advanced age |
| Sunlight | Lupus erythematosus | Li-Fraumeni syndrome | Immunosuppressive therapy, eg following transplant |
| Diet | Oral submucous fibrosis Actinic keratosis |
The major risk factors for head and neck squamous cell cancer (HNSCC) are tobacco smoking5 and heavy alcohol consumption.6 When looked at synergistically, there is a multiplicative interaction between these risk factors7 which can adversely affect the treatment outcomes for this cohort of patients.8 Cessation of tobacco use and alcohol consumption can significantly decrease the risk of developing head and neck cancers. After 20 years of smoking or alcohol cessation, the risk of developing head and neck cancer reaches that of non-smokers or drinkers.9
The role of human papilloma virus-16 (HPV-16) is increasingly recognized as a risk factor in oropharyngeal cancer,4 with between 9–61% (mean 51%) being HPV-16 positive.10 The role of other HPV subtypes in HNSCC are not yet fully understood, nor are the opportunities for reducing this risk, however, it has been suggested that vaccination against HPV could help to prevent HPV-positive oropharyngeal cancers.11
Premalignant lesions or systemic conditions, such as leukoplakia, erythroplakia and acquired immunodeficiencies, also pose a risk for the development of head and neck cancers. Example clinical presentations of the common oral lesions are given in Table 2.
| Urgent | Prompt | Non-Urgent |
|---|---|---|
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Finally, a diet which is low in fruit and vegetables is thought to increase the risk of developing head and neck cancer.12
Early diagnosis of head and neck cancer is recognized to affect survival rates for patients dramatically (Table 3).14,15 Dental professionals are in a unique position to recognize lesions of the head and neck and, to this effect, there is a great degree of importance to full extra-oral and intra-oral examination.16
| Classification of Head and Neck Cancer | Net 5-year Survival Rate |
|---|---|
| Hypopharyngeal | 28% |
| Sinus | 51% |
| Oral cavity | 56% |
| Tongue | 60% |
| Laryngeal (male only) | 65% |
| Oropharyngeal | 67% |
| Salivary gland | 67% |
Examination should include palpation of the lymph nodes of the neck and thorough examination of the intra-oral soft tissues. Suspicious lymph nodes will feel hard, fixed (at a late stage) and non-painful, in contrast to inflamed lymph nodes that will be tender to palpation and move more freely. High risk sites of mouth cancer include the floor of the mouth, lateral border of the tongue and the retromolar regions but, increasingly, lesions are also being diagnosed on the soft and hard palate, gingiva and buccal mucosa.17
Dentists should be aware of the large variation in presenting signs and symptoms of head and neck cancer. Typically, cancerous oral lesions present as:
Guidance for the referral of suspicious oral lesions has been produced by NICE in the document Suspected Cancer, Recognition and Referral, 2015.18 This guidance can assist with decision-making for urgent ‘2 week wait’ referrals and to distinguish lesions which require prompt and non-urgent review by secondary care units (Table 4).18
| Urgent (Within 2 weeks) | Prompt | Non-Urgent |
|---|---|---|
| Unexplained ulcer persisting for >3 weeks | Lichen planus | Polyps |
| Unexplained red or white patch which is painful, swollen or bleeding | White patches without redness or ulceration | Fibrous epulis |
| Persistent swelling of oral mucosa for >3 weeks | Unilateral salivary gland swellings | Recurrent oral ulceration |
| Unexplained lump in the neck or recently changing lump | Chronic hyperplastic candidosis | Mucoceles |
| Unexplained tooth mobility not associated with periodontal disease | Oral sub-mucous fibrosis | Pyogenic granuloma |
| Unexplained persistent and sore throat | Amalgam tattoos | |
| Hoarseness persisting for more than 3 weeks | Traumatic ulcers |
Referrals for those lesions which warrant urgent review should be sent to the local Oral and Maxillofacial service via the correct referral process for that department (note that some centres are now moving to electronic Referral Management Systems (RMS)). Information on the referral process can be found online or by contacting the departmental secretaries. Correspondence should be clearly marked as ‘urgent’ for rapid processing and it is the duty of the receiving Trust to see that patient within 2 weeks of receipt. It is also useful to contact the department to ensure that a referral has been received. Should there be doubt of the validity for urgent referral, clinicians should contact their local Oral and Maxillofacial service for advice. See Figure 3 for an example of a local referral form for suspected head and neck cancer.19
Clinical photography may be useful in these cases to document the lesion, but primary care providers are encouraged not to biopsy or disturb suspicious lesions.
Following a confirmed positive biopsy of a cancerous head or neck lesion, a diagnostic work-up involving further examination and investigations will be instigated by the head and neck multidisciplinary team (MDT), whose full role and responsibilities will be discussed in the next article.
The grade and stage of the lesion will be identified alongside assessment of patient comorbidities to develop the most suitable treatment pathway:20
The TNM (T = tumour size, N = nodal involvement, M = metastatic spread) classification20 is most commonly used to stage head and neck cancers. Figure 4 provides an overview of the TNM staging classification for head and neck cancers.
From December 2017 an updated version (version 8) of the TNM classification system was implemented by the International Union Against Cancer (UICC).21 This considers a new classification for HPV p16 positive oropharyngeal tumours, separate classification of nodal involvement for all head and neck sites and, amongst others, a new classification for SCCs of the skin of the head and neck. Currently, the guidance is considered complex and UK units are advised to continue to use version 7 of the TNM staging system.22
Staging is important for identification of the prognosis of tumours and to aid the treatment decision-making process. The prognosis for head and neck cancer drops by 50% when there is spread to lymph nodes (N1), and decreases further with increasing stages, highlighting that early diagnosis is paramount.15 T0–T2 lesions are usually successfully treated with a single treatment modality (surgery or radiotherapy), whereas higher stages will require adjunctive or palliative treatment. T4a and T4b indicate the surgical operability of the tumour, where T4b stage is considered inoperable.23
Tumours with a high risk of recurrence are associated with the following features:
The treatment modalities for stages of head and neck cancer, and their side-effects, will be discussed in more detail in the next article of this series. Outlined in Table 3 are the 5-year net survival rates for adults with different head and neck cancer diagnoses.2 In addition, HPV positive patients will experience improved survival outcomes in comparison to HPV negative patients.24 The treatment modalities for stages of head and neck cancer and their side-effects will be discussed in more detail in the next article of the series.
With head and neck cancer becoming more prevalent in the UK, dentists are ever more likely to encounter patients at various stages along their journey. Dental practitioners have a role to play in the diagnosis of malignant lesions of the head and neck and should understand what requires urgent, prompt or non-urgent referral and the process these should follow. Dentists should also have an understanding of the basis of the TNM classification, and the implications that this has on treatment and prognosis for the patient. The second and third articles in this series will discuss the journey the patient takes from diagnosis through treatment and then onto rehabilitation.
