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Aging Skin: Blemishes and Nonmelanoma Skin Cancers


An in-depth report on the diagnosis, treatment, and prevention of age-related skin problems.

Alternative Names

Actinic Dermatitis; Actinic Keratoses; Skin Cancer; Sun Protections and Sunscreens

Skin Cancer

Skin cancer is now more common than all human cancers combined. In one study of people over 50 years, 65% had significant skin problems, including precancerous lesions and skin cancers. In fact, according to the American Cancer Society, more than a million non-melanoma skin cancers are diagnosed every year. Melanoma, although less common than the other two major skin cancers, is the most dangerous.

Risk Factors for Skin Cancers

Sunlight and Ultraviolet Radiation. By far the most significant risk factor for all skin cancer is exposure to UV radiation.

Other Risk Factors. Other factors may increase the risk for specific skin cancers, including the following:

  • A family history of skin cancer.
  • Fair skin. While skin cancers affect all ethnic groups, they are most prevalent among those with lightly pigmented skin and become increasingly less common the darker the skin. Redheaded people have the highest risk followed by blondes. Skin cancers also tend to proliferate among older persons.
  • Conditions that impair the immune system, such as HIV.
  • Immunosuppressant drugs.
  • High and regular exposure to certain toxic compounds such as creosote, radium, and arsenic.
  • Psoriasis. Patients with psoriasis are at higher risk for skin cancers from phototherapy used to treat psoriasis. In addition, some evidence also suggests that the disease itself appears to be a risk factor for nonmelanoma skin cancers.


Anyone with risk factors for skin cancers should be vigilant:

  • Check the entire body every month or so.
  • Use mirrors or have a partner examine the back, scalp, soles of the feet, and other hard-to-see spots. (Use a hair dryer to separate hair in order to examine the scalp.)
  • Experts suggest drawing a map of the body indicating locations of moles, areas of discoloration, lumps, or other blemishes. Whenever a person conducts a self-examination, the map is checked for new lesions, lumps, or moles and for changes in shape, color, and size.
  • If any suspicious areas are found, individuals should see a dermatologist or be sure their primary care physician is able to recognize skin cancers. (Primary care physicians may not always be as well trained as specialists in detecting skin cancers.)


Melanoma is the most serious of skin cancers. It is named for the skin cell from which it arises, the melanocyte, which produces pigment, or melanin. As people age, these pigment-forming cells often proliferate, forming harmless moles (called nevi).

Infrequently, however, the cells grow out of control and become melanomas, which are malignant and can be life threatening. Once relatively uncommon, malignant melanoma is increasing at an alarming rate, faster than any other cancer.

When melanoma is confined to the outer layer of skin, it is curable in 90% of cases. But if unchecked it can continue to spread to lymph and blood vessels, which increases the likelihood of its affecting distant sites in the body.

A mnemonic device, ABCD, is used to describe several features that help to distinguish melanomas from noncancerous growths:

  • Asymmetry (A). About half the time, a melanoma develops in an existing mole; in other cases, it arises as a new lesion that can resemble an ordinary mole. A non-cancerous mole, however, is generally symmetric and circular in shape, while melanoma usually grows in an irregular, asymmetric fashion.
  • Border Irregularity (B). Benign lesions generally have clearly defined borders that mark the boundary between mole and skin. A melanoma, in contrast, often has notched or indistinct borders that may signal ongoing growth and spread of the cancer.
  • Color Variation (C). One of the earliest signs of melanoma may be the appearance of various colors within the lesion. Because melanomas arise within pigment-forming cells, they are often varicolored lesions of tan, dark brown, or black, reflecting the production of melanin pigment at different depths within the skin. Occasionally, lesions are flesh colored or surrounded by redness or lighter areas of depigmentation. Pink or red areas may result from inflammation of blood vessels within the skin; blue areas reflect pigment in the deeper layers of the skin; and white areas can arise from dead cancerous tissue.
  • Diameter (D). A diameter of 6 millimeters or larger (about the size of a pencil eraser) is worrisome. Melanomas start out small; by the time a lesion has grown this large, other abnormalities will most likely be present. No matter what size, any suspicious lesion should be examined by a physician.

Individuals most at risk for melanoma tend to have a fair or freckled complexion, blond hair with blue, green or gray eyes, skin that burns easily, a history of sunburn, especially as a child or teenager, and a family history of melanoma.

Treatment consists of surgery, which can be curable if the cancer has not yet spread to the lymph nodes and to other sites in the body. Several new strategies for combating metastatic melanoma are being explored, including boosting the body's natural immune response to fight the disease.

Basal Cell Carcinomas

Basal cell carcinoma (BCC) is named for the round basal cells located in the lower part of the epidermis (the outermost layer of the skin), from which it arises. It is the most common skin cancer and, like melanoma, has been increasing at a dramatic rate.

Prevalence and Risk Factors. Basal cell carcinoma occurs in 800,000 people every year, and 30% of people, almost exclusively Caucasians, can expect to have basal cell carcinoma, on average, by age 55. Some experts posit that genetic mutations caused by factors other than sunlight may also contribute to basal cell cancer.

Interestingly, a 2001 study reported that people with more wrinkles were less likely to develop basal cell carcinomas, even among high-risk groups. Some experts suggest that people prone to wrinkles may respond to sun exposure with biologic mechanisms that protect against basal cell carcinoma. More research is needed confirm this.

Characteristics. The lesions usually develop later in life in areas that have received the most sun exposure, such as the head, neck and back, and especially the nose. About a third of basal cell carcinomas appear in areas not exposed to the sun.

Basal cell carcinomas (BCCs) are highly variable in appearance:

  • They usually appear as a round area of thickened skin that does not change color or cause pain or itching.
  • Very slowly, the lesion spreads out and develops a slightly raised edge, which may be translucent and smooth. Infrequently, basal cell carcinomas resemble malignant melanomas in color.
  • Eventually, the center becomes hollowed and covered with a thin skin, which can become sore and open.
  • A form known as aggressive-growth basal cell carcinoma resembles a scar with a hard base. This is type is more likely to spread and must be treated very aggressively.
Basal cell cancer
Basal cell cancer is a malignant skin tumor involving cancerous changes of basal skin cells. Basal cell skin cancers usually occur on areas of skin that are regularly exposed to sunlight or other ultraviolet radiation. Once a suspicious lesion is found, a biopsy is needed to prove the diagnosis of basal cell carcinoma. Treatment varies depending on the size, depth, and location of the cancer. Early treatment by a dermatologist may result in a cure rate of more than 95%, but regular examination by a health care provider is required to watch for new sites of basal cell cancer.

They are sometimes hard to tell from benign skin conditions. For instance, occasionally they arise in unexposed skin, where they may mimic an ordinary mole, cyst, or pimple. They may be particularly difficult to distinguish from benign cysts when they occur near the eyes.

Outlook. Usually, basal cells are slow growing and they are rarely fatal. Most basal cell carcinomas need not be treated as an emergency, although late treatment can cause disfigurement, so they should be removed as early as possible.

The basal cell carcinomas that are most likely to spread are larger ones (more than 1 centimeter), scar-like BCCs, particularly those located on the cheek, and any BCC on the nose, neck, earlobe, eyelid, or temple.

Some studies are indicating that people with basal cell carcinoma may be at higher risk for second cancers, including melanoma, cancer of the lip, salivary glands, larynx, lung, breast, and kidney and non-Hodgkins lymphoma. Those at higher risk for such cancers appear to be men and anyone diagnosed before 60 with BCC.

Squamous Cell Carcinoma and Bowen's Disease

Characteristics. Squamous cell carcinoma (SCC) develops from keratinocytes, flat, scale-like skin cells that lie under the top layer of the epidermis. The majority of squamous cell carcinomas occur on sun-exposed areas, especially the forehead, temple, ears, neck, and back of the hands. People who have spent considerable time sunbathing may develop them on their lower legs. Their appearance changes with its stage:

  • Squamous cell carcinoma in situ (often referred to as Bowen's disease). This is the earliest stage when the cancer is local and has not spread. Lesions are typically large reddish patches (often over one inch) that are scaly and crusted.
  • Invasive squamous cell carcinoma. These are lesions that are highly likely to spread (metastasize). They enlarge either rapidly (over months) or slowly (over years). Eventually they become ulcerated.
Click the icon to see an image of squamous cell cancer.

Prevalence and Risk Factors. About 160,000 people develop squamous cell carcinomas every year. The incidence of this cancer is increasing.

Sun exposure and sun damage are the greatest risk factors, and the addition of other factors compound the risk:

  • Older age.
  • Being fair skinned, particularly having red hair.
  • Living in sunny climates.
  • Treatments for psoriasis, including PUVA (psoralen and UVA radiation) and immunosuppressant agents, such as cyclosporine, also pose a risk for squamous cell carcinoma (SCC).
  • Genital warts (human papillomavirus) may also increase the risk in the genital and anal areas and around fingernails.

Outlook and Severity. Prompt treatment is desirable because squamous cell carcinomas are more likely to spread to local lymph nodes than are basal cell carcinomas, the other common skin cancer. Mortality rates for this cancer are very low, although squamous cell cancer still kills between 2,000 and 2,500 Americans each year. The risk for metastases (the spread of cancer to other organs) ranges from 0.5% to 16%, depending on risk factors. Squamous cell carcinomas most likely to spread include the following:

  • Deep lesions, those larger than 2 cm in diameter, or patches with poorly defined margins.
  • Recurrent lesions.
  • SCC on neck, earlobe, eyelid, lips, or temple.
  • SCC that develop in ulcers.
  • SCC that develops on skin areas that have been previously treated with radiation or exposed to carcinogenic chemicals.

People with squamous cell carcinomas seem to be at higher risk for other cancers, including melanoma itself, lung cancer, non-Hodgkin lymphoma, bladder cancer, leukemia, and testicular and prostate cancer in men and breast cancer in women.

Precancerous Skin Disorders

Actinic (Solar) Keratoses. Actinic (also called solar) keratoses are the most common of all precancerous skin lesions. In fact, evidence now strongly supports the belief that actinic keratoses are actually squamous cell carcinomas in situ (the early stage of SCC). It should be noted, however, that not all actinic keratoses progress to carcinomas. One long-term study in 1999 indicated that the rate of malignant transformation might be about 10% over a 10-year period, while other studies show higher rates of progression to SCC.

Actinic keratoses occur after years of sun exposure and afflict over half of Caucasian persons aged 40 or older who live in hot sunny climates. They occur predominantly on sun-exposed skin such as the face, neck, back of the hands and forearms, upper chest, and upper back. Men may develop keratoses along the rim of the ear.

Actinic keratoses have the following characteristics:

  • Lesions typically occur on the surface of the skin and have a sandpaper-like feel. In fact, they are sometimes more easily felt than seen.
  • Most lesions are pink and even flesh-colored. Some are red or brown, scaly, and tender. At times, they can resemble melanomas and even dermatologists may have trouble telling the two apart.
  • They can range in size from microscopic to several inches in diameter.

Keratoacanthomas. Keratoacanthomas closely resemble squamous cell carcinomas but they are not malignant. The majority arises in sun-exposed skin, usually on the hands or face. They are typically skin colored or slightly reddish when they first develop but their appearance typically changes:

  • In the early stages, keratoacanthomas are smooth, red, and dome shaped.
  • Within a few weeks, they can grow rapidly, usually to one or two centimeters. Some reach the size of a quarter in less than a month and can be rather disfiguring.
  • They eventually stop growing and become crater-like with an outer rim of tissue surrounding and a sometimes crusty interior.

Most will spontaneously regress within a year but they almost always scar after healing. Also about 25% develop into squamous cell carcinomas, most frequently in older people and in sun-exposed areas. Removal by surgery (sometimes by radiation) is recommended. They may also be treated with 5-fluorouracil, either as a cream (Efudex) or with injections.


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