Squamous Cell Carcinoma

What is Squamous Cell Carcinoma ?

Squamous cell carcinoma of the skin is an invasive rumor arising from keratinizing epidermal cells; it has the potential for metastasis. Squamous cell carcinoma occurs most commonly in fair-skinned white men over age 60. Outdoor employment and residence in a sunny, warm climate (southern United States and Australia, for example) greatly increase the risk for squamous cell carcinoma.

Lesions on sun-damaged skin tend to be less invasive with less tendency to metastasize than lesions on unexposed skin. Notable exceptions are squamous cell lesions on the lower lip and the ears; almost invariably, these are markedly invasive metastatic lesions with a poor prognosis.

Causes of Squamous Cell Carcinoma

Predisposing factors associated with squamous cell carcinoma include overexposure to the sun's ultraviolet rays, radiation therapy, ingestion of herbicides containing arsenic, chronic skin irritation and inflammation, exposure to local carcinogens (such as tar and oil), hereditary diseases (such as xeroderma pigmentosum and albinism), and the presence of premalignant lesions (such as actinic keratosis or Bowen's disease).

Rarely, squamous cell carcinoma may develop on the site of smallpox vaccination, psoriasis, or chronic discoid hipus erythematosus.

Signs & Symptoms of Squamous Cell Carcinoma

When SCC is confined to the epidermis, it is called squamous cell carcinoma in-situ, sometimes referred to as Bowen's disease. It becomes invasive when it penetrates through the epidermis and into the dermis.

Lesions appear as pink, rough, scaly patches or nodules that have a tendency to bleed. The growth is typically firm and sometimes extends inward as well as outward in the skin. As the tumor grows, it ulcerates and scabs over.

SCC frequently develops on the face, lips, ears, and hands. Metastasis to other parts of the body can occur. The incidence of metastatic SCC varies; however, larger and deeper lesions especially on the lips, hands, temples, and ears are more likely to spread.

Diagnostic Tests

The appearance of the skin lesion may indicate a squamous cell carcinoma. A biopsy and examination of the lesion confirms the diagnosis.

Treatment

The size, shape, location, and invasiveness of a squamous cell tumor and the condition of the underlying tissue determine the treatment method; a deeply invasive tumor may require a combination of techniques. All the major treatment methods have excellent cure rates. In most cases, the prognosis is better with a well-differentiated lesion than with a poorly differentiated one in an unusual location.

Depending on the lesion, treatment may consist of wide surgical excision; curettage and electrodesiccation, which offer good cosmetic results for smaller lesions; radiation therapy, which is generally for older or debilitated patients; chemotherapy; and chemosurgery, which is reserved for resistant or recurrent lesions.

The chemotherapeutic agent fluorouracil is available in various strengths ( 1%, 2%, and 5%) as a cream or solution. Local application causes immediate stinging and burning. Later effects include erythema, vesiculation, erosion, superficial ulceration, necrosis, and reepithelialization. The 5% solution induces the most severe inflammatory response but provides complete involution of the lesions with little recurrence.

Prevention Tips

• Sun exposure and sunbathing produce gradual skin damage even if sunburn is avoided. Ten to forty years can pass between the time of sun exposure and the development of a squamous cell skin cancer.
• Some who have had a squamous cell carcinoma need to come back every three months for two years for a skin exam and then every six months for life. Most recurrences are in the first two years.
• Self-examination is important for early detection. It is easier to treat smaller skin cancers, and the risk of spreading is reduced in smaller lesions.