What is Melanoma?
Melanoma is less common than basal cell carcinoma and squamous cell carcinoma—the other leading forms of skin cancer—but it is by far the deadliest. Unfortunately, the incidence of melanoma has been increasing. Melanoma develops from melanocytes, cells located primarily in the skin that produce the dark pigment melanin, which serves to protect the skin from ultraviolet radiation. People with darker skin produce more melanin and generally are at less risk for all skin cancers, including melanoma, than those with pale skin. There is a relationship between sunburn, especially repeated sunburns before age 20, and skin cancers.
Family history and skin type also affect skin cancer risk. Melanomas may develop anywhere on the body regardless of sun exposure, including the eyes, although this is rare. The most common sites are areas intermittently exposed to the sun, such as the trunk and legs. There are four types of melanoma. Three types begin as tumors confined within a site (in-situ), usually within the upper portion of the epidermis. The fourth type is very invasive and quickly penetrates into the lower skin layers and spreads to other areas within the body.
Most cases of melanoma—more than 70%—are of a type called superficial spreading melanoma (SSM). SSM changes slowly, usually over a period of one or more years. It often appears as a dark, flat, or slightly raised mark on the skin with variegated colors. Its borders are irregular, with indentations or notches. In women, SSM often occurs on sun-exposed surfaces of the skin over the shin. In men, it occurs most often on the back of the torso and along the front of the legs. SSM can also occur on the soles of the feet. Superficial spreading melanoma mostly appears after puberty. In young people, this is the most common type of melanoma.
SSM has two growth phases. The radial phase involves expansion of the lesion through the epidermis (upper skin layer). In the early radial phase, the lesion is thin, and it can remain in this phase for months or years. This is the less threatening of the two phases, because once the melanoma enters into the vertical growth stage, the prognosis worsens. In the vertical growth phase, the melanoma grows into the dermis (deep skin layer) and underlying structures. At this point, the cancer is a dangerous malignancy and has the ability to invade other tissues and metastasize.
Lentigo maligna melanoma (LMM) is similar to SSM in that it initially stays close to the skin’s surface. But it is the least common variant of melanoma. It occurs most often on the nose and cheeks and it is more common in older patients, typically in people in their 70s. The lesions are flat and tan, brown, black, or other colors. The borders can be scalloped and convoluted, and they commonly grow to fairly large sizes, 3 to 6 centimeters or larger. Like superficial spreading melanoma, lentigo maligna tends to spread slowly along the surface layers of the skin. Lentigo maligna does not tend to metastasize as some other melanomas do.
Acral lentigous melanoma (ALM) is mostly seen in dark-skinned people and only rarely in Caucasians. This form of melanoma appears on the palms of the hands, the soles of the feet, or on nails. Lesions are usually brown, black, or multicolored with irregular borders, and flat or nodular. When it develops on the nail, it usually involves the thumb or big toe and may be seen as a black linear band, often with a discolored surrounding cuticle. ALM may look like a bruise, blood blister, or brownish-black blotch on the toe or finger. Fortunately, ALM grows rather slowly spreads along the surface before penetrating the skin's deeper layers. ALM may involve only a part of the nail, or it may affect the entire nail and surrounding tissue. Lesions may have a streaked appearance with some parts having well-defined, highly irregular borders, and others having a blurred appearance.
Nodular melanoma (NM) is the one form of melanoma that doesn’t begin in situ. It arises very rapidly, is the most aggressive type of melanoma, and is the second most common type, accounting for 15% to 20% of cases. Unlike SSM, which tends to spread outward, nodular melanoma grows rapidly upward and inward. NM usually develops in unblemished skin rather than in a nevus. It is often in a fully invasive stage of growth when it is diagnosed. NM has a typical skin cancer pattern. It is most common in light-skinned people and usually affects areas of skin that are frequently exposed to the sun, such as the arms, legs, head, neck, and scalp. NM usually develops in middle-age. NM characteristically appears as a uniformly black-colored nodule, a small, knot-like bump, although the nodule also may be brown, blue, gray, tan, or even red. It feels very round, and the borders are smooth and regular. These lesions often are mistaken for blood vessel abnormalities because of their berry color and texture.
A specific form called amelonatic melanoma usually appears as a red or flesh colored bump and, since it does not appear as a dark mole, is often overlooked. Consequently, amelonatic melanomas often are very deep once discovered and tend to have a poorer prognosis than other forms of melanoma.
Who Gets Melanoma?
According to the National Cancer Institute, in 2013 there were an estimated 76,690 new cases of melanoma and 9,480 deaths. Anyone can develop melanoma, but the risk is 10 times higher for Caucasians compared with blacks. People who are fair-skinned, such as those with red or blond hair and have blue or green eyes, people who are sun-sensitive or burn easily, and people who have more than 50 moles, large moles or unusual-looking moles are at an increased risk. In addition, sun exposure and sunburn during childhood and adolescence increase the likelihood of skin damage later in life. In fact, there has been an increase in the incidence of melanoma among young women, largely due to the popularity of indoor tanning salons; from 1970 to 2009, the incidence of melanoma increased by 800% among young women and by 400% among young men.
- Any change in a mole’s appearance. Such changes are characterized by the acronym ABCDE: asymmetrical shape; border irregularity; color variation; diameter larger than a pencil eraser; evolving, is the lesion changing in shape, size or color or looks different from other moles?
- An irregularly shaped flat spot or raised bump anywhere on the skin. The spot or bump may be brown, black, blue, tan, red, white, or multicolored; it usually has no symptoms. Only occasionally will it be tender, itchy, or ooze or bleed.
- A black or brown spot on the color portion (iris) or the white (sclera) of the eye; change of color of the iris; gradual loss of vision; pain and redness in the affected eye.
- The cause of melanoma is unknown; however, it is likely a combination of genetic factors and environmental sun exposure.
- Exposure to ultraviolet (UV) radiation from the sun or from artificial sources, such as sunlamps or tanning beds, may promote melanoma. Skin damage and melanoma risk increase with cumulative UV exposure. Spending more time in the sun with less clothing coverage is believed to be a factor in the increasing incidence of skin cancer. According to the American Academy of Dermatology, indoor tanning bed use is associated with a 75% increased risk of developing melanoma.
- Hereditary factors play a role in some forms of melanoma, as there are several known genetic defects that will lead to melanoma; a family history of melanoma increases the risk.
- People with pale skin, blue or green eyes, and red or blond hair are most at risk for skin cancer. However, anyone of any age or skin color may develop melanoma.
- The presence of atypical moles (as differentiated by the acronym ABCD; see Symptoms) increases risk.
- Having many moles on the skin is a risk factor.
- A congenital mole, one that is present at birth, has an increased chance of developing a melanoma within it. With very large moles, this may occur before age five; with small moles, this may occur at any time, even in old age.
- The risk of melanoma increases steadily with age.
What If You Do Nothing?
Left untreated, melanoma may quickly metastasize, or spread, to other parts of the body, which is why it is the most dangerous form of skin cancer. Metastasized melanoma is potentially and frequently fatal, making detection and treatment critical.
- Because most melanomas arise on areas of skin that can be easily examined, early detection and successful treatment often is possible. Most dermatologists can accurately diagnose melanoma in 80% to 90% of cases. How the growth looks, the patient's history of a new or changing growth raises suspicions of melanoma, and, in many cases, a biopsy or small sample of skin is obtained for evaluation under a microscope to make a diagnosis.
- The “ABCDE” method from the American Academy of Dermatology is intended to evaluate the characteristics of skin lesions to detect melanoma. This method involves the following:
Asymmetry: Does one half of the lesion resemble the other half?
Border: Is the border of the lesion irregular or poorly defined?
Color: Does the color of the lesion vary from one area to another?
Diameter: Is the lesion the size of a pencil eraser or larger?
Evolving: Does the lesion look different than other lesions on the skin? Has it changed in color, shape, or size?
- Epiluminescence microscopy is a diagnostic test that can be used to help make a diagnosis. In this test, the doctor uses a hand-held device called a dermatoscope to examine the lesion. Certain diagnostic criteria are used to help determine if the lesion is benign or malignant.
- Imaging tests include newer diagnostic procedures that involve computer imaging, lasers, and other devices. In dermascopy, the dermatologist uses a hand-held device called a dermascope to visualize pigment in the skin. This test can be used to enhance features of skin lesions and diagnose melanoma. In some cases, nearby lymph nodes are tested to determine if cancer cells have spread.
- Sentinel lymph node biopsy involves injecting a dye is into the tumor site where it travels to the nearest lymph node and stains it. The lymph node is removed and examined under a microscope for melanoma cells to help determine the stage of the disease. Using sentinel lymph node biopsy to predict the course of melanoma is still somewhat controversial as it does not appear to extend the life of a person with melanoma.. Some maintain that it helps to remove tumor cells before they have a chance to spread to more distant sites, and others claim that migrating tumor cells can bypass these lymph nodes and that the procedure is unnecessary. Lymph nodes also may increase the ability of the immune system to fight the cancer and removing them might reduce this ability.
- Surgery to remove a melanoma with margins of normal skin determined by the size of the cancer is the standard treatment. In some cases, neighboring lymph nodes may be removed to determine whether the melanoma has spread. Melanoma that remains confined to the skin is almost 100% curable.
- Chemotherapy and radiation therapy may be used in advanced cases of melanoma to forestall cancer growth and thus ease symptoms, although these treatments rarely result in a cure. Melanoma that has spread to lymph nodes or to distant sites requires additional treatment.
- Adjuvant therapy includes immunotherapy using interferon alpha 2b or interleukin-2. These are immune-stimulating chemicals that help the body "fight" the cancer. In 2011, the U.S. Food and Drug Administration (FDA) approved ipilimumab (Yervoy) to treat metastatic melanoma. This drug, which is a monoclonal antibody, may help the body's immune system to recognize, target, and destroy melanoma cells. In an international study, ipilimumab improved survival in patients with late-stage disease. Side effects include diarrhea, fatigue, rash, and intestinal inflammation. This medication increased the risk for severe autoimmune reactions and its approval includes a strategy (Risk Evaluation and Mitigation Strategy) to inform doctors of these serious risks.
- The medication vemurafenib (Zelboraf) was approved in 2011 to treat a certain type of melanoma that cannot be treated surgically and/or that has spread (metastasized). This drug may be used for late-stage melanoma that contains a certain genetic mutation called BRAF V600E. Also included in this approval is a diagnostic test to identify the specific mutation. Side effects include joint pain, rash and sun sensitivity, hair loss, fatigue and nausea.
- Two newer drugs were approved in 2013 to treat metastatic melanoma and melanoma that cannot be removed surgically. One of the drugs—dabrafenib (Tafinlar)—is used to treat melanoma that contains the genetic mutation BRAF V600E (Tafinlar). The other drug—trametinib (Mekinist)—is directed at a gene mutuation called V600K. The drugs can have serious side effects, including cutaneous squamous cell carcinoma, kidney failure, heart failure, and extremely low blood pressure, and they can also cause infertility in men and women.
- Radiation therapy may be used to destroy cancerous cells within the eye.
- Melanoma vaccine is a promising, new development currently under clinical investigation. A melanoma vaccine works like immunotherapy is that it boosts the body's natural defenses against established skin cancer, but it does not prevent melanoma. The vaccine, which is not yet commercially available, prompts the immune system to recognize and kill the remaining tumor cells before they reproduce and grow. The melanoma vaccine has an overall response rate of 10% to 20%. Attempts to increase the immune-stimulating effects of the vaccine are being undertaken.
- The most effective way to reduce your risk of melanoma (or any skin cancer) is to avoid or minimize sun exposure. UVB rays are at their strongest, and most damaging, between 10 am and 2 pm. Try to avoid being directly exposed during this window of time. If you must be in the sun, be extra-vigilant about protecting your skin.
- Use a broad-spectrum (UVA/UVB) sunscreen with an SPF of 30 or higher whenever you are in the sun. Apply at least two tablespoons to your body 30 minutes before going in the sun and then reapply every two hours or right after going in the water. Choose a sunscreen designed for an active lifestyle if you play sports or sweat a lot.
- Cover up. Sunscreen is effective when used properly, but it's not magic. Broad-brimmed hats, long sleeves and UV-blocking sunglasses further protect the skin and eyes.
- Stay away from tanning salons. Sun lamps used in tanning salons emit doses of UVA that are as much as 12 times stronger than those delivered by the sun. Research has shown that people who use tanning salons are 2.5 times more likely to develop squamous cell carcinomaand 1.5 times more likely to develop basal cell carcinoma.
- Examine your skin monthly. Eighty% of skin cancers are found by patients and their family members. Once a month, give your skin a head-to-toe once-over, and ask your partner to look at your back. If you see something suspicious or unfamiliar, have a doctor check it out. To perform a self-exam, stand in front of a mirror and slowly inspect the entire surface of the skin, checking for changes in existing moles and for the appearance of any new skin lesions or spots. Do not neglect hard-to-see areas; a second mirror may help. Regular self-examination aids in early diagnosis and treatment.
- Get annual checkups. Schedule regular doctor's visits at least once a year. Make sure your skin gets a thorough going-over, and ask questions about any spots you're concerned about.
- If you're at high risk, ask your doctor for a mole map. A mole map is a series of photographs of the entire surface of your skin. Typically, you keep one copy and your doctor keeps one, providing a baseline reference for tracking moles. By referring to these photos during skin self-exams or office visits, patients and physicians are better able to determine when a change has occurred in any mole on the body. People who have had one episode of melanoma are at greater risk of developing a second melanoma. For this reason, preventive measures are especially important after initial diagnosis.
When To Call A Doctor
- Make an appointment with a dermatologist if you notice a change in the appearance of a mole or a new unidentified growth. Most skin growths are harmless, but if there is any question, a simple skin biopsy may be done to determine the presence or absence of cancer.
- Schedule regular follow-up appointments with a dermatologist after an episode of melanoma, because of the increased likelihood of subsequent episodes.
- Have regular skin cancer screenings with a dermatologist if you have a family history of melanoma or are in a high-risk category for melanoma or other skin cancers. Relatives of high-risk people should also be screened regularly.
- See an ophthalmologist if you develop symptoms of melanoma in the eye.
Reviewed by Kevin Berman, M.D., Ph.D., Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network.