Malignant Melanoma

Definition

Melanoma is an illness in which cancer cells form in melanocytes, the cells that give skin its color. In malignant melanoma, melanocytes become cancerous and may spread throughout the body and invade other organs and tissues. Initially melanoma begins on the surface of the skin. If left untreated, melanoma can cause illness that may be fatal; however, if caught early, melanoma may be treatable with surgery, chemotherapy , radiation therapy, and immunotherapy.

Description

The epidermis, the outermost and upper layer of the skin, contains melanocytes, the skin cells that make melanin, the pigment that gives skin its hue. Melanin is responsible for the color of a person's skin, hair, and eyes. When a cancerous tumor develops in the melanocytes, a person has malignant melanoma.

Most cases of melanoma occur in the skin, but sometimes melanoma can also occur in the colored part of the eye, a condition known as intraocular melanoma.

Sometimes melanoma arises out of normal skin, but it can also develop in a mole (also called a nevus). Moles are benign growths or collections of melanocytes on the skin. According to the American Academy of Dermatology, individuals have typically about 30 moles on their skin.

The number and type of moles individuals have may increase the risk of developing melanoma. People with more than 50 moles or with moles that are unusual and irregular looking (doctors call these dysplastic or atypical moles) are at increased risk of developing melanoma.

There are four major types of melanoma:

Superficial spreading melanoma accounts for 70% of all cases of melanoma and typically occurs in younger people. This type of melanoma takes a long time to penetrate the top layer of skin, and the first sign of it is a flat or slightly raised skin lesion. The lesion may be discolored with irregular borders and may develop out of a previously benign mole. It is most likely to occur on the trunk in men, the legs in women, and the upper back in men and women.

Lentigo maligna melanoma is another form of melanoma that is most often found in older adults. It begins as a flat or slightly raised tan, brown, or dark brown skin discoloration that remains close to the skin's surface. Once the malignancy spreads, it is referred to as lentigo maligna melanoma.

Acral lentiginous melanoma is the most common type of melanoma in African Americans and Asians and is least common among Caucasians. The black or brown discoloration of acral letiginous melanoma first spreads on the surface of the skin, often under the nails or on the soles of the feet or palms of the hands.

Nodular melanoma, which accounts for 10 to 15% of all melanoma cases, is the most aggressive form of melanoma, and by the time it is diagnosed, it may have spread to other areas of the body. This type of melanoma starts as a bump that is usually black. Most frequently nodular melanoma is found on the trunk, legs, and arms, and most often affects older people.

Superficial spreading melanoma, lentigo maligna melanoma, and acral lentiginous melanoma begin as

in situ malignancies, which means they only affect the top layers of skin. Eventually, these forms of melanomas may become invasive and spread to other areas of the body. Nodular melanoma is often invasive by the time it is diagnosed, however.

Invasive melanomas are more severe and more difficult to treat.

Demographics

In the United States, one in 85 people are expected to develop melanoma during their lifetime. According to American Cancer Society (ACS) estimates, 68,480 cases of melanoma were expected to be newly diagnosed in the United States in 2008.

Malignant melanoma occurs in people of all ages and ethnicities. However, certain factors put people at greater risk for developing this disease, including the following:

• having fair skin
• having red or blond hair
• having blue or green eyes
• being older than 20 years
• having excessive sun exposure, exposure to artificial ultraviolet light (such as in tanning beds), or a history of sunburns
• having a close relative with melanoma
• having lots of moles
• having moles that are unusual or irregular-looking

Because the development of melanoma is usually related to sun exposure, people with less melanin and lighter skin, hair, and eyes are at greater risk. The disease is 10 times more common in whites than in African Americans.

Rates of melanoma increase with age and are highest in those in their 80s, according to the ACS.

Having certain procedures or health conditions that weaken the immune system may also predispose a person to developing melanoma. Compared to people in the general population, those who have undergone organ transplants have a threefold risk of melanoma. Having human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS ), other forms of cancer, or autoimmune diseases that require immunosuppressive treatments can also increase a person's risk of developing malignant melanoma.

Causes and symptoms

As of 2008 physicians did not know exactly why melanoma develops in some people but not others. What they do know is that excessive exposure to the sun, especially as a child or young adult (such as having an outdoor summer job for several years), and having severe, blistering sunburns increase the likelihood that a person will develop melanoma.

The development of melanoma is also thought to have a strong genetic link, since many people who develop melanoma also have family members with the disease. In fact, researchers discovered a gene called BRAF that may play a role in the development of melanoma. A mutated form of BRAF, found in two-thirds of melanoma samples analyzed in one study, is thought to switch on the malignant cells, allowing them to grow and divide. Another gene mutation, called p53, has also been associated with melanoma cases among families.

The first sign of melanoma is a mole, sore, lump, or growth found on the skin. Melanoma can occur anywhere on the body, but it is most often found on the backs of men and the legs of women. Generally, melanomas are black or brown, but may be red, skin-colored, or white.

Changes in a mole's appearance over time may also indicate malignant melanoma. Sometimes, a growth or mole may bleed, ooze, or itch, which indicates malignancy. Having satellite moles, new moles that grow near an existing mole, may also point to this form of skin cancer .

People with moles, lumps, or growths that fit these criteria should be checked by a doctor.

Diagnosis

For older adults who find an abnormal mark or mole on the skin, the first step should be to contact their healthcare providers for a skin examination. The doctor or nurse will carefully examine all moles, birthmarks, and pigmented areas over the person's entire body, including the back, legs, hands, feet, and scalp.

Doctors often use the “ABCDEs” when making a diagnosis of melanoma. They include:

• Asymmetry: Melanomas are usually asymmetrical, with one half different than the other.
• Border irregularity: The edges of a melanoma may be ragged or blurred.
• Color: A malignant melanoma often has several colors or shades, whereas benign moles are typically one color.
• Diameter: Cancerous moles are usually larger than a pencil eraser (about 6 millimeters).
• Evolving: An area of skin that has recently undergone changes.

If the healthcare provider finds a spot that has one or more of these criteria, he or she will remove cells from the abnormal area so they can be examined by a pathologist, a procedure called a biopsy. The doctor may remove as much as possible of the suspicious area so that the pathologist can check the entire sample for cancer cells.

After a person has been diagnosed with melanoma, doctors may use additional tests and procedures to determine the stage of the cancer, a process referred to as staging. Staging helps identify whether and to what extent cancer has spread throughout the body and helps guide the type of treatment the patient will receive. In the earlier melanoma stages (Stage I and Stage II), the tumor is smaller and remains in the top layers of the skin. In later melanoma stages (Stages III and IV), the melanoma is thicker and has spread to other parts of the body.

Chest x rays, computed tomography (CT or CAT) scans, magnetic resonance imaging (MRI) scans, and positron emission tomography (PET) scans are tests that doctors use to determine the spread of melanoma throughout the patient's organs and tissues. In addition, surgeons may remove additional tissue from around the melanoma (a procedure called wide local incision) so it can be checked by a pathologist for additional cancer cells. The lymph nodes may also be biopsied to determine if the cancer has spread to these tissues.

Treatment

Most thin melanomas in the early stages are treated by removing the cancerous cells and a portion of surrounding skin tissue. If a biopsy shows that cancer has spread to the lymph nodes, then they may need to be removed as part of treatment. Sometimes people undergoing surgical treatment for melanoma may also need skin grafts to cover the surgical wound.

In addition to surgery, doctors may recommend treating the melanoma with radiation therapy, chemotherapy, or immunotherapy.

In radiation therapy, ionizing radiation is aimed directly at the tumor, thereby killing cancerous cells.

In chemotherapy treatment, a patient takes potent drugs designed to kill cancer cells or stop them from dividing. Melanoma patients may also undergo a particular type of chemotherapy treatment called hyperthermic isolated limb perfusion. In this procedure, a tourniquet is used to stop blood flow to the arm or leg that has the melanoma. Chemotherapy drugs are then injected into the bloodstream, allowing the medication to stay primarily in the area where the cancer is.

Immunotherapy involves taking medications that stimulate the immune system, causing the body to destroy the melanoma cells or slow the progression of the disease throughout the body. A specific type of immunotherapy called biologic therapy involves administering interferon-alpha to melanoma cancer patients. This drug, a chemical that is already produced by the body in smaller amounts, has potent side effects but can kill tumor-producing cancer cells.

Nutrition/Dietetic concerns

Some research suggests that eating a diet rich in antioxidants , folic acid , fats, and proteins and whole, unprocessed foods may aid in the prevention of skin cancer such as melanoma. Specific plant flavonoids have also been studied for their skin-protective properties, including apigenin (found in vegetables, fruits, tea, and wine), curcumin (found in the spice turmeric), resveratrol (found in grape skins, red wine, and peanuts), and quercetin (found in apples and onions).

Prognosis

Melanoma is less common than other forms of skin cancer, but it is the most deadly type of this disease. In 2008, the American Cancer Society estimated that 8,420 people might die because of melanoma in 2008. However, the majority of people with melanoma are diagnosed in the early stages. Early detection of melanoma is linked to higher rates of survival.

Whether the melanoma has spread to the body's organs and the thickness of the lesion at the time of diagnosis have significant impact on the prognosis. The thicker the melanoma and the greater the spread, the worse the prognosis.

Other factors may also influence survival rates. For example, although melanoma among African Americans is rare, it is more lethal. Melanomas also tend to be thinner in females, so women have more favorable survival rates.

QUESTIONS TO ASK YOUR DOCTOR

How does my sun/ultraviolet light exposure history affect my risk of melanoma?

• How often do I need skin examinations for melanoma?
• Do I have any moles or lesions that I should watch carefully?
• How far has my melanoma spread beneath the skin?
• What is my prognosis, based on the stage of melanoma I have?
• Are there risks and side effects associated with cancer treatment?
• How should I care for my skin after melanoma treatment?
• What steps should I take to avoid sun exposure now that I have been treated for melanoma?

In addition, older adults generally have shorter survivals after melanoma diagnosis.

Prevention

To prevent melanoma from developing, avoiding or reducing the amount of sun and ultraviolet light exposure is critical.

Older adults should always apply a sunscreen with a sun protection factor (SPF) of 15 or higher every day during all seasons. In addition, wearing protective clothing and accessories, such as hats, sunglasses, and long sleeves, can reduce the amount of sun exposure to the skin.

The sun's rays are strongest between 10 a.m. and 2 p.m., so if possible, seniors should complete outdoor activities before or after these hours, especially during the summer. People should avoid lying in the sun or using tanning beds in order to further reduce sun exposure.

To identify melanoma in its earlier stages when it is easier to treat, the American Cancer Society recommends that all people older than 40 get professional skin examinations every year. In addition, older adults or their caregivers should examine the skin monthly to check for suspicious growths or moles and contact their healthcare providers if they have concerns.

KEY TERMS

Biopsy —Removal of cells or tissues so a pathologist can examine them for abnormalities or cancer cells.

Flavonoid —A plant-derived chemical compound thought to have antioxidant properties.

In situ —In place, not having invaded other sites.

Malignant —A tumor that is cancerous and may spread to nearby tissue and other parts of the body.

Mole —A benign group of pigmented cells on the surface of the skin. A mole is usually dark and is sometimes raised.

Ulceration —A break in the skin that occurs when cells die.

Caregiver concerns

Caregivers of those with malignant melanoma may find themselves helping to feed, dress, and bathe the patient during and after cancer treatment. They may need to help change bandages, drive the person to doctor appointments, or manage insurance or financial issues if the person is incapacitated by cancer treatments.

To get support, caregivers can talk to a nurse or social worker about recommendations for a local cancer support group. Involvement in support groups gives caregivers the chance to learn what to expect, share stories, and find support while they care for loved ones with cancer.

Resources

BOOKS

Eldridge, Lynne, and David Borgeson. Avoiding Cancer One Day at a Time: Practical Advice for Preventing Cancer. Edina, MN: Beaver's Pond Press, 2006.

Nouri, Keyvan. Skin Cancer. Columbus, OH: McGraw Hill, 2007.

ORGANIZATIONS

American Academy of Dermatology, PO Box 4014, Schaumburg, IL, 60168-4014, (847) 330-0230, (888) 462-DERM (426-3376), (847) 330-0050, www.aad.org.

American Cancer Society, 250 Williams Street NW, Atlanta, GA, 30303, (800) ACS-2345 (227-2345), www.cancer.org.

National Cancer Institute, 6116 Executive Blvd., Room 3036A, Bethesda, MD, 20892-8322, (800) 422-6237, [email protected], www.cancer.gov.

Skin Cancer Foundation, 149 Madison Ave., Suite 901, New York, NY, 10016, (212) 725-5176, 212-725-5751, [email protected], www.skincancer.org.

Amy Sutton