Clinical presentation and diagnosis of oral cancer

Early diagnosis of oral cancer should lead to better treatment results and, ideally, the clinical diagnosis of oral cancer should be easy. Oral lesions, unlike those at many other sires, give rise to early symptoms. In general, patients become aware of and usually complain about minute lesions within the mouth and biopsy may be carried our under local analgesia. Yet, despite all the above, between 27 and 50 per cent of patients present for treatment with late lesions. Many of these patients are elderly and frail and, therefore, delay the effort of visiting their doctor or dentist. Many of this group of patients wear dentures and are accustomed to discomfort and ulceration in the mouth and thus see no urgency in seeking treatment. Furthermore, the practitioner is often not suspicious that a lesion may be malignant and the lesion is often treated initially with antifungal therapy, antibiotics, steroids and mouth-washes, thus contributing to further delay in the ultimate diagnosis and treatment. Another factor is that oral cancer is not usually painful until such rime as either the ulcer becomes secondarily infected or the tumour invades sensory nerve fibres.

The tongue

The majority of tongue cancers occurs on the middle third of the lateral margins, extending early in the course of the disease on to the ventral aspect and floor of the mouth (Fig. 41.8). Approximately 25 per cent occur on the posterior third of the tongue, 20 per cent on the anterior third and rarely (4 per cent) on the dorsum.

Early tongue cancer may manifest in a variety of ways. Often the growth is exophytic with areas of ulceration. It may occur as an ulcer in the depths of a fissure or as an area of superficial ulceration with unsuspected infiltration into the underlying muscle. Leucoplakic patches may or may not be associated with the primary lesion. A minority of tongue cancers may be asympromatic, arising in an atrophic depapillated area with an erythroplakic patch with peripheral streaks or areas of leucoplakia.

Later in the course of the disease a more typical malignant ulcer will usually develop, often several centimetres in diameter. The ulcer is hard in consistency with heaped-up and often everted edges. The floor is granular, indurated and bleeds readily. Often there are areas of necrosis. The growth infiltrates the tongue progressively causing increasing pain and difficulty with speech and swallowing. By this stage pain is often severe and constant, radiating to the neck and ears. Lymph node metastases at this stage are common — indeed 50 per cent may have palpable nodes at presentation. Because of the relatively early lymph node metastasis of tongue cancer, 12 per cent of patients may present with no symptoms other than ‘a lump in the neck’.

  The floor of the mouth

The floor of the mouth is the second most common sire for oral cancer (Fig. 41.9). It is defined as the U-shaped area between the lower alveolus and the ventral surface of the tongue; carcinomas arising at this sire involve adjacent structures very early in their natural history. Most tumours occur in the anterior segment of the floor of the mouth to one side of the midline.

The lesion usually starts as an indurated mass which soon ulcerates. At an early stage the tongue and lingual aspect of the mandible become involved. This early involvement of the tongue leads to the characteristic slurring of the speech often noted in such patients. The infiltration is deceptive but may extend to reach the gingivae, tongue and genioglossus muscle. Subperiosteal spread is rapid once the mandible is reached. Lymphatic metastasis, although early, is less com­mon than with tongue cancer. Spread is usually to the sub­mandibular and jugulodigasrric nodes and may be bilateral.

Cancer in the floor of the mouth cancer is associated with a pre-existing leucoplakia more commonly than at other sites.

The gingiva and alveolar ridge

Carcinoma of the lower alveolar ridge occurs predominantly in the premolar and molar regions (Fig. 41.10).

The patient usually presents with proliferative tissue at the gingival margins or superficial gingival ulceration. Diagnosis is often delayed because there is a wide variety of inflammatory and reactive lesions which occur in this region in association with the teeth or dentures. Indeed, there will often be a history of tooth extraction with subsequent failure of the socket to heal prior to definitive diagnosis. Another common story is that of sudden difficulty in wearing dentures. Regional nodal metastasis is common at presentation, varying from 30 to 84 per cent, although false-positive and false-negative clinical findings are common.

The buccal mucosa

The buccal mucosa extends from the upper alveolar ridge down to the lower alveolar ridge and from the commissure anteriorly to the mandibular ramus and retromolar region posteriorly (Fig. 41.11). Squamous cell carcinomas mostly arise either at the commissure or along the occlusal plane to the retromolar area, the majority being situated posteriorly. Exophyric, ulcero-infiltrative and verrucous types occur. They are subject to occlusal trauma with consequent early ulceration and often become secondarily infected. The onset of the disease may be insidious, the patient sometimes pre­senting with trismus due to deep neoplastic infiltration into the buccinaror muscle. Extension posteriorly involves the anterior pillar of the fauces and soft palate with consequent worsening of the prognosis. Ulcero-infiltrative lesions will often involve the overlying skin of the cheek resulting in multiple sinuses. Lymph node spread is to the submental, submandibular, parotid and lateral pharyngeal nodes.

Verrucous carcinoma occurs as a superficial proliferative exophytic lesion with minimal deep invasion and induration. Often the lesion is densely keratinised and presents as a soft white velvety area mimicking benign hyperplasia. Lymph node metastasis is late and the tumour behaves as a low-grade squamous cell carcinoma.

The hard palate, maxillary alveolar ridge and floor of antrum

These three sites are anatomically distinct, but a carcinoma arising from one site soon involves the others (Fig. 41.12). Consequently, it can be difficult to determine the exact site of origin. Except in countries where reverse smoking is practised, cancer of the plate is relatively uncommon. The majority of squamous cancers arises in the antrum and later ulcerates through to involve the hard palate. The majority of malignant tumours arising from the palatal mucosa is of minor salivary gland origin. Palatal cancers usually present as sessile swellings which ulcerate relatively late. A finding in contrast to mandibular alveolar tumours is that deep infiltration into the underlying bone is uncommon.

Carcinomas arising in the floor of the maxillary anrrum often present as palaral tumours. Although the fully established picture of antral carcinoma is difficult to miss, the early symptoms are nonspecific and may mimic chronic sinusitis. tumours of the lower half of the antrum below Ohngren’ s line usually present with ‘dental’ symptoms because of early alveolar invasion. The commonest presenting feature is pain, swelling or numbness of the face. Later symptoms of nasal obstruction, discharge or bleeding, and dental symptoms such as painful or loose teeth, ill-fitting dentures, oroantral fistula or failure of an extraction socket to heal, soon follow. Lymph node metastasis from carcinomas of the palate and floor of the antrum occurs late but carries a poor prognosis.

Diagnosis

The diagnosis of intraoral carcinoma is primarily clinical, and a high index of suspicion is necessary for all those clinicians seeing and treating patients with oral symptoms. A careful and detailed history with particular attention to recording the dates of the onset of particular signs and symptoms precedes the clinical examination. All areas of the oral mucosa are carefully inspected and any suspicious lesion is palpated for texture, tethering to adjacent structures and induration of underlying tissue.