Some cancers are more common in aging skin. The underlying cause of skin cancer in older people is often the accumulated damage of many years of excessive exposure to the sun. In some cases there may be a genetic predisposition to skin cancer—either "cancer in the family" or the inheritance of a type of skin that increases risk for skin cancer. All skin cancers can be successfully treated if they are discovered and treated early. All are potentially disfiguring, and potentially fatal if they metastasize (spread) to other parts of the body.

The three most common forms of skin cancer are:

• Basal cell carcinoma—develops in 300,000 to 400,000 persons every year in the United States

• Squamous cell carcinoma—develops in 80,000 to 100,000 persons per year in the United States

• Melanoma—45,000 to 50,000 new cases are diagnosed every year in the United States. Melanoma is the deadliest form of skin cancer—6 of every 7 deaths from skin cancer in the United States are due to melanoma

Basal cell carcinoma arises in a layer of skin (basal layer) beneath the skin’s surface. It seldom metastasizes, although it may do so if the cancer invades lymph or blood vessels that can carry cancer cells to distant organs. The major spreading mechanism of basal cell carcinoma is by local invasion of surrounding skin tissue. If left untreated, it may become large and disfiguring.

The major risk factors for developing basal cell carcinoma are:

• excessive and chronic sun exposure over many years

• a fair (white) skin complexion, especially when hair is blond or red

While basal cell carcinoma has traditionally been a cancer associated with older people, it is now seen in more young adults than in the past.

Early detection of basal cell carcinoma can lead to early treatment and prevention of disfigurement. The most likely places for basal cell carcinoma to develop are areas exposed to sun—face, scalp, ears, neck, shoulders and back. Criteria to look for in self-examination:

• a small, pearly nodule, which may or may not have telangiectasia (small enlarged blood vessels) on the surface; the nodule increases in size slowly and may form an ulceration in its center; there may be some pigmentation

• a solitary, flat or slightly depressed lesion that is hard to the touch; it may be yellowish or whitish and have indistinct borders

• one or more reddish, scaling plaques that slowly enlarge; these lesions may resemble dermatitis or psoriasis

Any suspicious lesion should be examined immediately by a dermatologist and biopsied if the dermatologist deems it necessary to determine proper treatment.

To view photos of basal cell carcinoma shown in various forms on various parts of the face, please click here.

The next photo illustrates the disfigurement that may follow late treatment of basal cell carcinoma:

Early, effective treatment of basal cell carcinoma by a dermatologic surgeon has a cure rate of more than 95%. However, new basal cell carcinomas can develop after treatment, so continued self-examination and regular examination by a dermatologist are important.

When basal cell carcinoma is discovered early and the diagnosis confirmed by biopsy, treatment may be carried out in the dermatologist’s office or an outpatient setting. Treatment procedures include:

• Curettage: A scalpel is used to scrape away malignant tissue. Electrocautery may be used after curettage to "mop up" any remaining cancer cells. Curettage is used chiefly for superficial carcinoma not previously treated.

• Cryosurgery: Liquid nitrogen is applied to the lesion to destroy malignant tissue by ultra-cold freezing.

• Topical chemotherapy: Cancer cells are destroyed by pharmacologic agents applied to the surface of the skin.

• Surgical excision: The cancer is surgically removed and the skin closed with stitches. This technique is used when the carcinoma is in deeper tissues.

• MOHS microscopic surgery: Surgical removal is performed under a microscope. In this technique, the surgeon can perform surgery layer by layer into the skin, under direct microscopic observation.

• Laser surgery: Cancerous tissue is destroyed by laser beam.

The dermatologist or dermatologic surgeon will discuss with the patient the type of treatment that will be most effective.

Squamous cell carcinoma develops in the outer layers of the skin. It is capable of metastasizing to other areas of the body if not treated early. It also spreads locally and may cause significant disfigurement.

The major risk factors for developing squamous cell carcinoma are:

• excessive, chronic exposure to sun, over many years

• overexposure or chronic exposure to x-rays

• long-term treatment with immunosuppressive drugs

• white skin, especially with blond or red hair

Criteria for self-examination:

• commonly appears as an ulcerated nodule or superficial erosion with poorly defined margins on the skin or lower lip; the lesion persists and does not heal

• a wart-like growth or plaque

• premalignant forms of squamous cell carcinoma include actinic keratosis, cutaneous horns (hard, fibrous growths), and Bowen’s disease (scaling, inflamed-looking plaques)

A suspicious lesion should be examined immediately by a dermatologist, and biopsied if deemed necessary by the dermatologist to determine proper treatment.

To view photos of several forms of squamous cell carcinoma shown on various parts of the body, please click here.

Squamous cell carcinoma can be significantly disfiguring if not treated early, as shown in these two photos:

When a diagnosis of squamous cell carcinoma is confirmed by biopsy, treatment options are similar to those for basal cell carcinoma.

As with basal cell carcinoma and squamous cell carcinoma, excessive and chronic sun exposure is a major risk factor for melanoma. There also is a tendency for melanoma to "run in the family", and to be associated with a familial trait of having many moles on the body. Melanoma often arises in a pre-existing mole or pigmented lesion. Early diagnosis and treatment of melanoma is essential. Any person with many moles or a family history of melanoma should be examined regularly by a dermatologist. Every adult should self-examine at regular intervals to detect any early indications of melanoma. Self-examination is done using the A-B-C-D criteria:

A=Asymmetry (the left side of the lesion is unlike the right side)

B=Border Irregularity (the lesion has a scalloped or poorly defined border)

C=Color Variation (not all parts of the lesion are the same color; 
within the lesion may be patches of tan, brown, black, pink, white or blue)

D=Diameter (a melanoma is usually larger than 6 millimeters in diameter,
 about the size of a pencil eraser)

It is worth noting that some melanomas do not conform to the A-B-C-D criteria, so any suspicious mole should be examined by a dermatologist.

For more and detailed information on the causes, prevention and treatment of melanoma, please see the MelanomaNet Web site.