Melanoma Skin Cancer
Overview
Skin cancer is the most common of all cancers. Between 40 to 50% of all cancer cases diagnosed every year are skin cancer.
There are two main types of skin cancer: malignant melanoma and nonmelanoma skin cancer
Nonmelanoma Skin Cancer - The the most common types are basal cell carcinoma and squamous cell carcinoma. Basal cell carcinoma forms in the thin, upper layer of the skin (epidermis). It is usually found on the sun-exposed areas of the body, such as the neck and head. About 75% of all skin cancers are of this type.
They are slow growing and do not usually spread. After treatment, basal cell carcinoma may grow again on the same spot or appear elsewhere on the skin. Between 35 to 50% of people who develop one basal cell carcinoma will grow a new skin cancer within five years of diagnosis.
Accounting for about 20% of all skin cancers, squamous cell carcinomas also form on the top, thin layer of the skin and are commonly seen on sun-exposed areas such as the face, neck, lips, neck or back of the hand. However, it can also develop in other locations, including the genital area. Squamous cell carcinoma is more aggressive than basal cell carcinoma and more likely to spread to other parts of the body.
Less common nonmelanomas (e.g., Kaposi's sarcoma and cutaneous lymphoma) make up less than one percent of nonmelanoma cancers.
Melanoma - Melanomas account for only four percent of all skin cancer cases but are far more dangerous. Of all skin cancer-related deaths, 79% are from melanoma. In this disease, cancer develops in cells (melanocytes) that produce skin pigmentation. A black or brown spot appears, typically, on the torso of males and lower legs of females. It may also form on the palm of the hands, soles of the feet and under the nails. Very rarely it appears in parts of the body not covered by skin, such as the mouth, eyes, vagina and internal organs. Melanoma is more likely than nonmelanoma skin cancer to spread to lymph nodes and other parts of the body.
Symptoms
Nonmelanoma skin cancer may cause the following symptoms:
- Spots or bumps that grow over time (a few months to a year or two) or that appear as a sore that does not heal within three months.
- Basal cell carcinomas may appear as flat, firm, pale areas or small, raised, translucent, pink or red, shiny, waxy areas with visible blood vessels or depressed center areas that bleed when slightly injured.
- Large basal cell carcinomas have oozing, crusty areas.
- Squamous cell carcinomas may look like small lumps with an uneven, rough surface or flat reddish patch that slowly grows.
Melanoma skin cancer may appear as
- Spots, sores, lumps, blemishes or markings on the skin that change in shape, size or color.
- Skin may become reddish, crusty or scaly.
- Skin may ooze, bleed or swell or may feel painful, scratchy or tender.
Causes and Risk Factors
The following factors increase your risk of getting skin cancer:
- Frequent exposure to ultraviolet (UV) rays. Sunlight is the main source of this exposure. Tanning lamps and tanning booths are other sources of UV radiation.
- Fair skin. Caucasians are 20 times more likely to develop skin cancer than African Americans. Fair-skinned individuals with red or blonde hair and skin that freckles or burns easily are also at greater risk.
- 50 years or older. Half of all melanoma cases occur in this age group. However, some melanoma cases also occur in people age 20 to 30 years. In fact, the most common cancer among people under 30 years old is melanoma.
- Family history. Individuals whose immediate relatives (mother, father, sister, brother, child) have been diagnosed with melanoma are considered at high risk. About 10% of melanoma cases show a family history of the disease.
- Reduced immunity. Individuals who have received medications that suppress the immune system, such as organ transplant recipients, are more likely to develop melanoma.
- Male gender. Men are two times more likely than women to develop basal cell carcinoma and three times more likely to develop squamous cell carcinoma.
- Exposure to chemicals. Arsenic (an ingredient in pesticides), paraffin, industrial tar, coal and certain types of oil may increase risk.
- Exposure to radiation. Individuals who have undergone radiation treatment are at risk to develop nonmelanoma skin cancer in the irradiated area.
- Severe skin injury. Scarring from burns, bone infections and other severe inflammatory skin diseases are risk factors.
- Psoriasis treatment. Patients receiving psoralen and UV light treatments (PUVA) may be at risk.
- Most people have moles, which are generally harmless. However, certain types can change in appearance, color or size and develop into melanoma. To distinguish between a normal mole and a melanoma, use the ABCD rule:
- Asymmetry - Half the mole looks different from the other half
- Border - The edges of the mole are irregular or ragged
- Color - Moles are non-uniform in color, and
- Diameter - Normal moles are typically smaller than six millimeters (a quarter inch) in diameter. Melanomas are generally bigger, although recently doctors have seen melanomas between three and six millimeters in diameter.
Diagnosis
A doctor will take a complete medical history and perform a physical exam. If abnormal markings are found, the doctor will perform additional tests. One such test is the biopsy, in which a skin sample is taken and examined in the lab. If lymph nodes are too large or too firm, a lymph node biopsy will also be done using a fine needle to remove a small piece of tissue from the suspected tumor. If this procedure does not indicate a clear result, a surgeon may remove the lymph node for further examination, usually in a doctor's office or at an outpatient clinic.
Treatment
Skin cancer may be treated with:
- Surgery to remove the malignant area
- Chemotherapy
- Radiation therapy or
- A combination of all of these.
The specific treatment will depend on the type of skin cancer, how advanced it is, how aggressive it is, where it is located and the general health of the patient.
Prevention
Skin cancer can be cured if detected early. The American Cancer Society recommends a cancer-related checkup with skin examination every three years for people 20 to 40 years old and annual exams for persons over 40.
Doctors suggest that patients perform monthly self-examinations in front of a full-length mirror. All areas of the body must be checked, including palms and soles, back of the torso and back of the legs. One out of three melanomas in men are on the back.
Other simple precautions are:
- Avoid being outdoors too long in intense sunlight. Peak hours to avoid are 10 a.m. to 3 p.m.
- Wear protective clothing when outdoors. You can protect yourself by simply wearing a shirt and a broad-rimmed hat.
- Use sunscreen. Sunscreen with SPF factor of 15 or higher should be applied to sun-exposed skin. Many sunscreens wear off from sweating or swimming and should be re-applied. Use sunscreen even on a hazy or cloudy day. Ultraviolet rays can still penetrate the atmosphere.
- Wear sunglasses. UV absorption of 99 to 100% is recommended to provide good protection for the eyes and the surrounding skin.
- Avoid other sources of UV light. Tanning beds and sun lamps can deliver damaging amounts of UV light to the skin and should be avoided or used lightly.
- Provide sun protection for children. Children should be cautioned about the harmful effects of excessive sun exposure. Parents should instill in their children the habit of using sunscreen and protective clothing for outdoor activities.
- Learn more about skin cancer. Many organizations, including the National Institutes of Health and the American Cancer Society, provide public service and information materials.
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