Articles

Oral cancers: what not to miss

06 September 2021

Dr Amanda Phoon Nguyen, Oral Medicine Specialist, looks at the unique position of dental practitioners in spotting the signs of oral cancer

When clinicians talk about oral cancer, they often mean oral cavity squamous cell carcinoma. However, the term “oral cancer” really refers to a heterogenous group of conditions encompassing the main subsites of the external lip, oral cavity and oropharynx.

It is important to consider and think of these as distinct entities, as they have differing presentations, aetiologies and risk factors and treatment options. A very large portion of oral malignancies are oral squamous cell carcinoma (OSCC), of epithelial origin. This is the eighth most common cancer worldwide. Early detection and prompt management is key to improving prognosis.

Despite technological advances over the past, the five-year survival rate of OSCC remains poor and is approximately 50% for all anatomical sites and stages. Cases that present with regional lymph node infiltration (Stages III and IV) are reported to have a five-year survival rate of 9–41%, compared to the 66–85% survival associated with cases without lymph node involvement (Stages I and II). The poor prognosis of oral cancer can largely be attributed to its frequent diagnosis at an advanced stage. Therefore, early detection is key.

OSCC is more common in the older population, and more common in females. It appears to be rising in the younger (<40 years) population. OSCC may be preceded by lesions termed oral potentially malignant disorders (OPMDs). The most common OPMDs are leukoplakia, erythroplakia, oral submucous fibrosis, actinic chelitis and oral lichen planus. The aetiology of oral cancer is multifactorial. Human papillomavirus (HPV) infection, most commonly HPV16 and 18, is implicated in oropharyngeal SCC. Alcohol and smoking are considered major risk factors, with a synergistic effect when used together. Other risk factors for OSCC include areca nut or betel quid chewing, other smokeless tobacco use, marijuana and qat use, use of alcohol containing mouthwash, a poor diet and genetic predisposition.

Evaluation of the head and neck area is a fundamental part of a comprehensive patient examination. Dentists play a critical role; there are few health professionals better placed to detect signs of more sinister pathology in the oral cavity and head and neck region.

Some red flags include:

Signs and symptoms for oral cancers and OPMD

Non-healing ulcerated lesion

Induration

Flat/slightly raised white, red, mixed white-red lesion

Exophytic, proliferative, papillomatous lesions

Mobile teeth

Pain or numbness in the mouth/face

Inability to wear dentures

Fixed, firm, mass

Solitary pigmented lesion

Non-healing extraction site

Mixed radiolucent/radiopaque lesions

Non-healing sore on the lips

Extraoral examination:

Site	Observations	Tips
Visual inspection of the patient in the waiting room and as they enter the dental operatory	Height and weight Personal hygiene Posture and gait Speech, mood and cognitive ability
Skin, nails, hair	Evaluate any other visible areas of skin, including the hands Pathology of note may include pigmented or ulcerated skin lesions, gross asymmetry, hair loss or nail changes	Close attention should be paid to sun-exposed areas such as the nose, ears or lips
Eyes	Observe general features and note any asymmetry
Temporomandibular joints and muscles of mastication	Detailed examination of the TMJs is out of the scope of this summary, however, evaluation should include if there is limitation in mouth opening, the end-feel, if there is swelling, joint sounds, and deviations or deflections with jaw movements. The normal range for maximum opening is variable (approximately 40-60mm) and may be obtained usung equipment such as a ruler	The muscles of mastication should be palpated with adequate pressure (1kg) If examination elicits pain, further investigated should be undertaken
Neck	Neck muscles, such as the sternocleidomastoids, posterior cervical muscles and strap muscles of the neck may be similarly palpated and evaluated for range of motion Mobility of the trachea can reveal if there is possible encroachment of neck neoplasms. The trachea can be palpated and moved laterally from midline to appreciate symmetric movement. Grating from the movement from the cartilaginous rings in normal The thyroid should be palpated for any nodules, asymmetry or swelling. When the patient swallows, the thyroid gland should move with the trachea	Pracitioners should feel comfortable performing this part of the extra-oral examination by the explaining to the patient the procedure and asking for the permission to proceed By pushing on the thyroid gently in a lateral direction, you can palpate the lobes of the thyroid gland. The left and right should be palpated in turn Dysphagia should not be ignored
Lymph nodes	Recall of the lymphatic drainage systems of the head and neck is important. An anatomy textbook or other online resources are useful to refresh knowledge in this area Lymph nodes should be assessed for enlargement, firmness and fixation to palpation. Tenderness to palpation is non-specific but should be reviewed	Looking for the outline of the sternocleidomastoid muscles, and asking the patient to lift and turn their head away from the side being examined is often helpful to identify the landmark and palpate the triangles of the neck which border this This lymph nodes should be palpated with adequate pressure (1kg) For the submandibular nodes, it may be helpful to gently pull the soft tissues laterally across the inferior border of the mandible and palpate the nodes against the border of the mandible