What is skin melanoma; symptoms and treatments

Related Terms:

BASAL CELL--one of the innermost cells of the deeper epidermis of the skin (Webster’s Dictionary, 9th ed.)

EPIDERMIS--the outer nonsensitive, nonvascular layer of the skin (Webster’s Dictionary, 9th ed.)

MELANOCYTES--the skin cells that produce melanin, the dark, protective pigment that causes suntans

CARCINOMA--a malignant tumor of epithelial origin (Webster’s Dictionary, 9th ed.)

BIOPSY--in order to confirm a diagnosis of cancer sample of tissue is removed and then examined under a microscope for evidence of cancerous changes

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SKIN CANCER:

Skin cancer is the most common form of cancer in the United States, with about 800,000 Americans being newly diagnosed each year with some form of skin cancer. The fact that the skin is so often exposed to the sun probably accounts for the frequency of skin cancer.

THREE MAIN TYPES OF SKIN CANCER:

The three main types of skin cancer are basal-cell carcinoma, squamous-cell carcinoma, and malignant melanoma. Basal-cell and squamous-cell carcinomas, the most common skin cancers, seldom become life-threatening, and with proper treatment they can almost always be completely cured.

The third type of skin cancer, malignant melanoma, is much less common but far more dangerous. If not detected early and treated promptly, malignant melanoma can quickly turn lethal. According to statistics compiled by the American Cancer Society, about 34,100 people develop malignant melanoma each year, and each year about 7,200 people die from the disease. Extrapolating from current rates, it is predicted that eventually one out of every one hundred Americans will develop this form of skin cancer.

BASAL-CELL CARCINOMAS:

Basal-cell carcinomas are the most common type of skin cancer. The basal-cell cancer usually appears as a small, pale patch that enlarges gradually. Eventually the growing patch will produce a central “dimple,” which will become ulcerated. Although part of the ulcer may heal, the main part of the cancer will usually remain ulcerated. Some but not all basal-cell carcinomas will show color changes.

Although basal-cell cancers can develop anywhere on the body, they are most likely to be found on skin that is frequently exposed to the sun—most commonly the face and hands, and frequently, though not as often, the arms and legs. Although fair-skinned people are more susceptible to developing basal-cell carcinomas, anyone, however dark his or her skin, can get them, especially if the individual does not take precautions to avoid over-exposing his or her skin to the sun.

SQUAMOUS-CELL CARCINOMAS:

Squamous-cell carcinomas resemble basal-cell carcinomas, and appear most often on the lower lip, the hands, and the ears. As with basal-cell carcinomas, squamous-cell carcinomas are more common among fair-skinned people, but anyone can develop them, especially under conditions of excessive exposure to the sun.

TREATMENT OF BASAL-CELL AND SQUAMOUS-CELL CARCINOMAS:

Several treatment options are available for basal-cell and squamous-cell carcinomas:

--surgery (a simple excision of the cancer)

--cryosurgery (removal by freezing)

--radiation therapy

--electro-dessication (the cancerous tissue is dried with a high-frequency current delivered through a needle electrode)

A malignant tumor is usually surgically removed. If the tumor is large, a skin graft may be required to patch the scar. Precancerous lesions are sometimes treated with topical chemotherapy.

MALIGNANT MELANOMA:

Malignant melanoma begins in the melanocytes, the skin cells that produce melanin, the dark protective pigment that is responsible for dark skin and suntans. Exposure to sunlight causes the melanin in the skin to increase, forming a protective layer.

When melanocytes become cancerous, they grow uncontrollably. Because they continue to produce melanin, melanomas characteristically have a dark pigmentation. They may be tan, brown, or black, or a single melanoma may mix several of these shades.

Unlike basal-cell and squamous-cell carcinomas, which almost never spread to other parts of the body, melanomas can be quite aggressive, spreading easily and rapidly to colonize vital organs. Once this happens, melanoma is very hard to treat, and the prognosis is much less promising.

Sometimes melanoma will appear on previously unblemished skin, but more commonly it begins on or near the site of a pre-existing mole or dark spot.

CAUSES:

The single most important risk factor for developing any kind of skin cancer, including malignant melanoma, is excessive exposure to the sun. People with fair skin and light (blue or green) eyes, and red or blond hair, are more susceptible to developing skin cancer, but the sun has damaging effects on anyone’s skin cells, regardless of skin color.

Some people believe that dark brown or black skin is a virtual guarantee against skin cancer, but this is simply not true. African-Americans can also develop melanoma, especially on the lighter skin on the palms of the hands, the soles of the feet, and under the nails. Everyone should take precautions to avoid unnecessary exposure to the sun.

People who work or play in the sun, especially in places where there is intense year-round sunshine, like Arizona, are at particular risk for developing skin cancer, and the chances increase as one ages, because the effects of sun exposure accumulate over time.

Another major risk factor for melanoma is having had at least one severe sunburn during one’s childhood.

People with many moles, and people who have relatives with melanoma are also at greater risk of developing this disease.

RECOGNIZING POTENTIAL MELANOMAS:

A melanoma can usually be distinguished from a normal mole by means of visual inspection. A normal mole is typically evenly colored (tan, brown, or black), it has sharply defined borders, and is less than about 6mmin diameter.

Many moles are already present at birth, but often one or more moles will appear spontaneously over one’s lifetime, especially on areas of skin that are frequently exposed to sunlight. Once a mole has developed, it will not usually change shape, size or color. Any sudden change in any of these characteristics is cause for concern.

Melanomas are usually characterized by one or more of the following signs:

(1) asymmetry—Whereas most moles have a fairly symmetrical round or oval shape, the shape or color of a melanoma may be asymmetrical—i.e., one side does not match the other.

(2) border irregularity—A mole usually has sharply defined borders; a melanoma may have ragged or blurred edges.

(3) color variation—a mole is usually evenly colored; the pigmentation of a melanoma is often not uniform. Different shades of tan, brown, or black may be present, and there may even be red, white, or blue mottling.

(4) diameter greater than 6mm—A mole does not usually get much larger than 6mm. An unusually large mole or one that suddenly or continuously begins to grow should be examined by a physician.

(5) surface changes—If a mole is marked by oozing, bleeding, or scaliness, or the development of a hard central core, it should be seen by a physician.

(6) changes in pigmentation—If pigment begins to spread beyond the original borders or if redness develops around the border, have the mole checked.

(7) Change in sensation—Be alert for signs of itchiness, pain or tenderness.

DIAGNOSIS:

Any suspicious mole or dark spot on the skin should be examined by a physician. If visual examination raises the possibility that the mole is a melanoma, the doctor will take a sample of the tissue and perform a biopsy to confirm the diagnosis.

TREATMENT:

If it is caught and treated in the early stages, melanoma is curable. Early melanomas are surgically removed, but in the later stages further treatment will usually be necessary. Treatment for advanced melanomas must be individualized.

PREVENTION:

Most melanomas could be prevented by reducing sun-exposure to a minimum, especially for those who have other risk factors for the disease. Avoid sun exposure, but when you must be out in the sun, wear protective clothing and use a sunblock rated at SPF-15 or higher on unprotected areas. (Even if the product makes claims to being water-proof, sunscreen must be reapplied after swimming or sweating.) No one should deliberately seek a suntan, whether outdoors or in tanning parlors. Besides being a major cause of skin cancer, sun exposure will also prematurely age and wrinkle the skin.

It is especially important for parents to protect the tender skin of their children from sun exposure. Not only is a child’s skin more delicate than an adults, but a severe sunburn during childhood is one of the major risk factors for developing malignant melanoma in later life.

SELF-EXAMINATION:

As with other forms of cancer, early detection of skin cancers through monthly self-exams provides the best prognosis for a complete cure. The American Cancer Society recommends that people become familiar with their own pattern of moles, freckles, beauty marks, etc., through a procedure called “mole-mapping.”

Then it is recommended that each person should perform a monthly self-exam to spot any changes in the number, size, shape, color, or surface texture of pigmented areas. Any noticeable change should be examined and, if necessary, biopsied by a physician.