Squamous Cell Skin Cancer (Carcinoma)
Squamous cell carcinoma (SCC) is an uncontrolled growth of abnormal cells arising in the squamous cells, which compose most of the skin’s superficial layers (the epidermis). SCCs often look like scaly red patches, open sores, elevated growths with a central depression, or warts; they may crust or bleed. SCC is mainly caused by the overall exposure over the course of a lifetime of an individual to the sun’s harmful ultraviolet (UV) rays. It can become disfiguring and sometimes deadly if allowed to grow and spread.
SCCs may occur on all areas of the body including the mucous membranes and genitals, but are most common in areas frequently exposed to the sun, such as the rim of the ear, lower lip, face, bald scalp, neck, hands, arms and legs. Often the skin in these areas reveals telltale signs of sun damage, such as wrinkling, changes in pigmentation, and loss of elasticity.
People who have fair skin, light hair, and blue, green, or gray eyes are at highest risk of developing the disease. But anyone with a history of substantial sun exposure is at increased risk. Those whose occupations require long hours outdoors or who spend extensive leisure time in the sun are in particular jeopardy. Anyone who has had a basal cell carcinoma is also more likely to develop a squamous cell carcinoma, as is anyone with an inherited, highly sun light-sensitive condition called Xeroderma Pigmentosum.
Squamous cell carcinomas are at least twice as frequent in men as in women. They rarely appear before age 50 and are most often seen in individuals in their 70s.
The majority of skin cancers in African-Americans are squamous cell carcinomas, usually arising on the sites of preexisting inflammatory skin conditions or burn injuries. Though naturally dark-skinned people are less likely than fair-skinned people to get skin cancer, it is still essential for them to practice sun protection.
Chronic exposure to sunlight causes most cases of squamous cell carcinoma. Frequent use of tanning beds also multiplies the risk of squamous cell carcinoma; people who use tanning beds are 2.5 times more likely to develop squamous cell carcinoma than those who don’t. But skin injuries are another important source. The cancer can arise in burns, scars, ulcers, long-standing sores and sites previously exposed to X-rays or certain chemicals (such as arsenic and petroleum by-products).
Chronic infections and skin inflammation can also give rise to squamous cell carcinoma. Furthermore, patients with immune deficiency like AIDS or patient undergoing chemotherapy and organ transplant patients receiving immune suppressant drugs are more likely to develop squamous cell cancer.
Certain precancerous growths, or precancers, most of them resulting from cumulative sun damage, can be associated with the later development of squamous cell carcinoma. A common precursor to squamous cell cancer is the precancerous growth called Actinic Keratosis. 40 to 60 percent of squamous cell carcinomas begin as untreated actinic keratoses.
Actinic Keratosis commonly occur on the lower lip, causing it to become dry, cracked, scaly and pale or white. Why the lower lip? Because it receives more sun exposure than the upper lip.
Leukoplakia is a whitish patch that appears on the mucous membranes of the tongue, gums, cheeks, or elsewhere inside the mouth and have the potential to develop into squamous cell carcinoma. They may be caused by sources of chronic irritation, such as habitual alcohol consumption or tobacco use, or rough edges on teeth or dentures. They may even be caused by a long-time habit of biting the inside of the lip; however, leukoplakias on the lips are mainly caused by sun damage.
Squamous cell carcinomas detected at an early stage and removed promptly are almost always curable and cause minimal damage. However, left untreated, they eventually penetrate the underlying tissues and can become disfiguring. A small percentage even metastasize to distant tissues and organs and can become fatal. Therefore, any suspicious growth should be seen by a physician without delay. A tissue sample (biopsy) will be examined under a microscope to arrive at a diagnosis. If tumor cells are present, treatment is required.
Fortunately, there are several effective ways to eradicate squamous cell carcinoma. The choice of treatment is based on the type, size, location, and depth of penetration of the tumor, as well as the patient’s age and general health.
Treatment can almost always be performed on an outpatient basis in a physician’s office or at a clinic. A local anesthetic is used during most surgical procedures. Pain or discomfort is usually minimal with most techniques, and there is rarely much pain afterwards.
The physician uses a scalpel to remove the entire growth, along with a surrounding border of apparently normal skin as a safety margin. The wound around the surgical site is then closed with sutures (stitches). The excised tissue is then sent to the laboratory for microscopic examination to verify that all cancerous cells have been removed. The accepted cure rate for primary tumors with this technique is about 92 percent. This rate drops to 77 percent for recurrent squamous cell carcinomas.
Other methods of removing the lesion may involve the use of heat produced by anelectrocautery needle that destroys tumor cells and controls bleeding at the same time. Freezing with nitrogen may the treatment of choice in patients with bleeding disorders or intolerance to anesthesia. However, it has a lower overall cure rate than the surgical methods.
X-ray beams directed at a tumor, also called radiation therapy are reserved for tumors that are hard to treat surgically, as well as patients for whom surgery is not advised, such as the elderly or those in poor health.
Sometimes, when the number of skin lesions is large, rather than attempting to surgically remove every lesion, a chemotherapeutic cream called 5-fluorouracil (5-FU) or imiquimod may be used to attack cancerous and precancerous cells.
Squamous cell carcinomas usually remain confined to the epidermis (the top skin layer) for some time. However, the larger these tumors grow, the more extensive the treatment needed. They eventually penetrate the underlying tissues, which can lead to major disfigurement, sometimes even the loss of a nose, eye or ear. A small percentage — estimates run from 2 to almost 10 percent – spread (metastasize) to distant tissues and organs. When this happens, squamous cell carcinomas frequently can be life-threatening.
Because most treatment options involve cutting, some scarring from the tumor removal should be expected. This is most often cosmetically acceptable when the cancer is small, but removal of a larger tumor often requires reconstructive surgery, involving a skin graft or flap to cover the defect.