Squamous cell carcinoma is the most common type of cancer affecting the mouth (oral cancer). About 90% of the cases of oral cancer are diagnosed as squamous cell carcinoma. The cancer can affect any part of the oral cavity but has a predilection for the lip, tongue and inner lining of the cheeks. Various factors are associated with development of squamous cell carcinoma including habits such as tobacco chewing and cigarette smoking.
The symptoms associated with squamous cell carcinoma often varies and are diverse in nature depending on the site and duration of the lesion.
Some lesions may be asymptomatic in nature while some produce more definitive symptoms in the early stages. The most common symptom of squamous cell cancer is an ulcer over the lining of mouth. In some cases there may be a reddish discoloration or patch of tissue.
Squamous cell cancer may develop from an existing leukoplakia, a lesion characterized by a white plaque-like discoloration of the oral mucosa that cannot be scrapped off. The tumor may also arise as an exophytic, fungating or papillary growth over the lining of oral cavity. The most common sites for squamous cell carcinoma include the vermilion border of lip, tongue, floor of the mouth, soft palate, gums, inner lining of cheeks, inner lining of lips and hard palate in descending order of frequency.
Oral squamous cell carcinoma is most commonly found in older men. The lesion is often associated with multiple factors such as :
- Tobacco smoking. Tobacco users are two three times more likely to suffer from squamous cell carcinoma as compared to non-tobacco users. Chronic use of cigars, cigarettes and dry snuff are also predisposing factors.
- Chewing betel quid or areca nut. Chewing betel quid is a common practice in the Indian subcontinent and Southeast Asia. It causes a precancerous disease known as oral submucosal fibrosis, which eventually leads to development of squamous cell carcinoma.
- Chronic alcohol use. Excessive alcohol use is also one of the factors in development of squamous cell carcinoma.
- Radiation exposure. X-ray radiation, ultraviolet radiation and other types of radiation can causes epithelial mutation and development of squamous cell carcinoma.
- Chronic irritation. Repetitive injury due to sharp tooth cusps, dentures or dental restorations can causes development of squamous cell carcinoma.
- Viral infections. Certain viruses are associated with squamous cell carcinoma. Most commonly associated virus is HPV (human papilloma virus).
- Dietary deficiency. Chronic iron deficiency can lead to Plummer-Visons syndrome causing increased risk of squamous cell carcinoma. Vitamin A deficiency is also implicated in epithelial cancers.
Treatment of sqaumous cell carcinoma depends on the stage at which the condition is diagnosed. Early lesions are treated with surgical excisions or irradiation. Intraoral squamous cell carcinomas are often treated with wide surgical excision to avoid recurrence and metastasis. The method and approach of surgery depends largely on the location of the lesion and surrounding vital structures. Reconstructive surgeries involving cheek, lip can be carried out once the tumor has been completely excised. Supportive therapy includes stopping risky habits and using vitamin supplements. The prognosis depends on the location and extent of the lesion.