Moles and skin cancer

Definition
Moles, also called nevi, are small accumulations of melanocytes (the cells that produce melanin, the pigment that colors hair and skin).

Causes/associated factors
Only 1 percent of infants are born with moles. Moles usually develop during childhood, and a few more may appear during adulthood. Nearly everyone has at least a few moles, which can be found anywhere on the body. Most moles are harmless, but some may become cancerous.
Here are a few facts about moles:

Moles may be flat or raised.
Most moles are evenly colored. They're typically tan, brown or flesh-colored.
Moles can have various shapes and sizes. Most are 6 millimeters or less in diameter (the size of a pencil eraser).
The edges are usually distinct.
Moles are usually symmetrical. (If you could fold them in half, the two sides would be identical.)
Some moles are hairy.
Some moles always look the same, and others change slowly over time. Moles often darken during pregnancy.
Moles sometimes disappear on their own as you age.
It's important to note that moles are different than freckles. Freckles are found only on areas exposed to the sun, are usually no bigger than a pea, and may darken during the summer and fade during the winter.


Skin cancer
In the United States, about 1 million people are diagnosed with skin cancer every year. More than 95 percent of cases are either basal cell carcinoma (a cancer that develops in the lowest layer of the epidermis, the outermost layer of skin) or squamous cell carcinoma (a cancer that develops in the middle layer of the epidermis). These types of cancers typically develop on parts of the body that are exposed to the most sun, including the head, neck, arms, legs, chest and back. Basal cell and squamous cell carcinoma are easily treated if caught early.
Melanoma (a cancer that develops in the deeper pigment-producing cells of the skin) is the most serious form of skin cancer. This type of cancer may develop at any age but is most common in adults. Melanoma can begin as a new pigmented skin growth, but most develop in an existing mole. Melanoma lesions are often found on the head, neck, trunk or legs, but they can appear anywhere. Melanoma is rare in dark-skinned people. When it does occur, it's commonly found on the palms of the hands, soles of the feet or under the nail beds. If not treated early, the cancer cells can spread to other parts of the body, often the brain, lungs or liver. Once melanoma spreads, it can be very difficult to treat. In the United States, melanoma causes most skin cancer deaths.

You face a higher risk of skin cancer if you:

have many moles
have large moles
have moles that are atypical in appearance or have a diagnosis of atypical moles
have a family or personal history of skin cancer
have freckles or light skin, hair and eyes
have excessive exposure to ultraviolet radiation through sunlight, light treatments or tanning booths
experienced one or more blistering sunburns as a child or teenager
are exposed to coal tar, pitch, creosote, arsenic compounds or radium on a regular basis

Signs/symptoms
To detect skin cancer at an early stage, especially if you're at high risk, it's important to examine your skin at home every month and have regular exams by your doctor. The American Cancer Society recommends using the "ABCD rule" for early detection. Consult your doctor or dermatologist if you notice any of the following "ABCDs" of moles:
Asymmetry: One half of your mole looks different than the other.
Border: The edges of your mole are ragged or irregular.
Color: Your mole has a mixture of colors or shades of colors, or you've noticed changes in the color of the mole or the surrounding skin.
Diameter: Your mole is more than 6 millimeters wide (about ¼ inch) or it has grown noticeably.

It's also important to consult your doctor or dermatologist if you notice:

an open sore that doesn't heal
spontaneous bleeding from a mole (bleeding not caused by trauma or irritation)
a mole that becomes itchy, tender, painful or begins to grow outward
a mole that scales, flakes, oozes or becomes lumpy
a new growth
a mole that reappears after it's been removed

Diagnosis
After carefully examining your skin, the doctor may recommend watchful waiting for moles that are old, haven't changed, or don't look like cancer. Color photos of your skin may be taken to include in your medical records. If a mole is irritated or bothersome, it may be removed.
Your doctor may remove part of a suspicious mole or the entire mole for a skin biopsy. If the mole turns out to be cancerous and was only partially removed for the biopsy, the rest of the mole and some of the nearby tissue will also be removed. Depending on the type, location and thickness of the mole, your doctor may recommend a procedure to identify and sample the lymph nodes, which drain the area of the skin cancer.


Treatment
The treatment and prognosis for skin cancer depends on the type of cancer, as well as how early the condition is diagnosed.
Basal and squamous cell carcinoma
Basal and squamous cell carcinoma are treated similarly, usually with a minor surgical procedure. Chemotherapy and radiation are usually reserved for skin cancers that have spread to other areas of the body. Radiation may also be used for people who may not tolerate surgery. Basal cell cancer rarely spreads, since it grows slowly. Squamous cell cancer can invade the tissues beneath the skin and spread if not caught and treated early.

Surgery: Various surgical procedures may be used to remove basal and squamous cell cancer. The type of surgery depends on the type, size and location of the cancer.

Curettage uses a scalpel to scrape away the lesion and may be followed by electrocautery to kill any leftover cancer cells. This technique may be used for superficial lesions.

Cryosurgery uses liquid nitrogen to destroy the cancerous lesion.

Excision involves cutting and removing the cancer, followed by stitching the area to close the wound. This technique is used if the cancer is deep.

Mohs' surgery involves removing the skin, layer by layer, until no more cancer cells are found. A microscope is used during the procedure to examine each layer of skin removed.

Laser surgery uses a laser beam to destroy the cancer.

Benefits of surgery: More than 95 percent of basal or squamous cell carcinomas are cured with early treatment.

Risks of surgery: Most of the surgical procedures are minor, but may cause scarring.
Chemotherapy: Chemotherapy is treatment with medications to kill the cancer cells. The medication may be given by mouth, into a vein or topically.

Benefits of chemotherapy: Chemotherapy may prevent the cancer from returning or spreading.

Risks of chemotherapy: The side effects of chemotherapy will depend on the specific medications given. Generally, these medications decrease the amount of white blood cells in the body that are responsible for fighting infection. Hair loss is a common side effect of chemotherapy. Topical therapy may cause red, sensitive skin.
Radiation therapy: High-energy X-rays are used to destroy cancer cells. Radiation therapy may be used in place of surgery or following surgery.

Benefits of radiation: Radiation may help prevent the cancer from returning or spreading.

Risks of radiation: Side effects may include red, dry, irritated skin.
Melanoma
Common treatment options for malignant melanoma include surgery, chemotherapy, radiation therapy and immunotherapy (using the body's immune system to fight cancer). Staging of the cancer (determining how thick and deep the melanoma is and whether it has spread) must be completed before treatment options can be decided. This may involve surgery, blood tests, chest X-rays and scans of certain organs.

Surgery: The standard treatment for melanoma is surgery. The surgeon will remove the melanoma and some normal tissue around it to ensure the removal of all the cancer cells in the area. If the melanoma is small and thin, the initial biopsy may be all that is necessary. Further surgery may be required to remove all the melanoma, however. If it's possible that the cancer has spread to nearby lymph nodes, a sentinel lymph node biopsy may be performed. With this procedure, a radioactive material is injected near the cancer. The first lymph node that absorbs this material, called the sentinel node, is removed. If this node contains cancer, the remaining lymph nodes in the area are also removed (a procedure known as lymph node dissection). If the sentinel node tests negative for cancer, then the remaining lymph nodes are left in place.

Benefits of surgery: If melanoma is diagnosed early, surgery may be successful and no further treatment will be needed.

Risks of surgery: Skin grafts may be necessary if large areas of skin and tissue are removed. If a lymph node dissection is performed, lymphedema (swelling from poor drainage and later buildup of lymphatic fluid) may occur in that limb. Surgery cannot cure melanoma that has metastasized (spread) to other parts of the body.
Chemotherapy: Chemotherapy is treatment with medications to kill the cancer cells. It may be offered if the melanoma has spread to other parts of the body. The medication may be given by mouth or by injection, usually as an outpatient treatment.

Benefits of chemotherapy: Chemotherapy may help control pain or other symptoms caused by the melanoma.

Risks of chemotherapy: The side effects of chemotherapy will depend on the specific medications given. Generally, these medications decrease the amount of white blood cells in the body that are responsible for fighting infection. Hair loss is a common side effect of chemotherapy.
Radiation therapy: High-energy X-rays are used to destroy cancer cells. Radiation therapy is typically done five days a week for several weeks.

Benefits of radiation: This type of therapy may help relieve symptoms and may also decrease the size of the melanoma.

Risks of radiation: Radiation side effects vary depending on the radiation dose and the area of the body treated. Hair loss and dry, red skin may occur at the radiation site. Fatigue is also a common side effect.
Immunotherapy: Immunotherapy (also called biological therapy) uses cytokines (a substance produced by the body to fight disease) made in the laboratory to fight the cancer cells. They can be given by injection under the skin or into a vein or muscle. The cytokines used may be interferon alpha-2b or interleukin-2.

Benefits of immunotherapy: If you are at high risk for recurrence, immunotherapy may be offered as a preventive treatment or to lengthen the time you are in remission.

Risks of immunotherapy: The side effects of immunotherapy include flu symptoms, bone marrow suppression (resulting in lower numbers of red and white blood cells) and possible liver or kidney damage.

Pregnancy-specific information
Moles often darken during pregnancy, probably due to hormonal changes. Researchers are uncertain if pregnancy increases the risk of developing melanoma, but melanoma most often develops during the childbearing years. When melanoma develops during pregnancy, it's often diagnosed at a later stage, possibly because it's thought to be a normal darkening of the mole. The prognosis and treatment options depend on the stage at which the melanoma is discovered. If you have concerns about a mole during pregnancy, consult your dermatologist.

Senior-specific information
The risk of developing skin cancer increases with age due to the accumulation of years of sun exposure. However, moles themselves sometimes disappear on their own as you age. If you notice any of the skin changes described above, consult your dermatologist.

Prevention
To help prevent skin cancer, keep these simple suggestions in mind:
Avoid excessive sun exposure and sunburns, including tanning booths and sunlamps.
Stay out of the sun from 10 a.m. to 4 p.m., when the sun's rays are the strongest.
Wear sunscreen with a sun protection factor (SPF) of 15 or higher. Use waterproof sunscreen if you'll be in water or warm enough to sweat.
When outdoors, reapply sunscreen every two hours. Wear sunglasses, a hat with a brim and protective clothing, such as long sleeves and pants.
Stay in the shade when possible.
Avoid reflective surfaces, such as large bodies of water.
Have regular skin exams by your health care provider.
To detect skin cancer at an early stage, remember to carefully examine your skin monthly for changes that may signal cancer. Early treatment is essential.