What is Melanoma:
Melanoma is a potentially serious form of skin cancer characterized by the uncontrolled growth of pigmented cells in the skin called melanocytes. Melanoma most commonly appears on normal-looking skin without a visible precursor, but 20-30% of melanomas develop within an existing mole. Melanoma has a good prognosis when it is detected and treated early. However, if left untreated, it can spread deeper into the skin and to other parts of the body, including the lymph nodes, lungs, liver, bones, and brain. Once melanoma has spread, it becomes more difficult to treat. However, there are many novel and cutting-edge systemic therapies that can help to treat metastatic melanoma and prolong life.
Main Types of Melanoma:
- Superficial Spreading: This is the most common type of melanoma and usually grows on the top layer of the skin before penetrating into the deeper layers. Its appearance can vary from flat to slightly raised, and it may have different shades of color or no color at all.
- Lentigo Maligna: This type of melanoma usually affects older people with extensive sun damage. Common sites of growth include areas that are frequently exposed, such as the scalp, face, ears, neck, and upper torso. This type of melanoma typically grows close to the surface of the skin before penetrating into the deeper layers. It can appear flat or slightly raised and usually has a darker shade of color.
- Acral Lentiginous: This is the most common type of melanoma that affects people of African or Asian descent. Commonly affected areas include the palms of the hands, underneath the fingernails, the soles of the feet, and underneath the toenails.
- Nodular: This is the second most common type of melanoma and most aggressive overall. It usually appears as a firm bump on the surface of the skin. It penetrates the skin more quickly than other types and is usually invasive at time of diagnosis.
Risk Factors:
Excessive UV exposure (from the sun or indoor tanning) is the most preventable risk factor for all skin cancers, including melanoma. If you’ll be in the sun, generously apply a sunscreen that has a Sun Protection Factor (SPF) of 30 or more and provides protection from both ultraviolet A (UVA) and ultraviolet B (UVB) rays to all exposed skin. Re-apply approximately every two hours, even on cloudy days, and after swimming or sweating.
Other risk factors include weakened immune system due to another medical condition or medication side effect, large number or size of moles, fair skin, family history of skin cancer, or previous personal history of skin cancer.
Things to Look Out For:
Moles are common. Almost everyone has a few and some people develop hundreds. Probably the most important thing to know about moles is that melanoma can develop in or near a mole.
Performing regular skin self-exams can help people recognize the early warning signs of melanoma. Dermatologists recommend that everyone perform regular skin self-exams. When examining moles, look for the ABCDE’s:
A: Asymmetry – one half does not look like the other half
B: Border – irregular, scalloped, or poorly defined borders
C: Color – varied from one area to another; look for shades of tan, brown, black, and sometimes white, red, or blue
D: Diameter – while melanomas are usually greater than 6mm (the size of a pencil eraser) when diagnosed, they can be smaller in early stages
E: Evolving – a mole or skin lesion that looks different from the rest or is changing in size, shape, color, or elevation
The Ugly Duckling Sign is another strategy for identifying melanoma. This sign is based on the concept that most of the normal moles on your body will be similar, while the melanoma will stand out like an ugly duckling. So along with the ABCDE approach, it is also important to compare the suspicious spot to its neighboring moles.
If a mole seems worrisome or is new and looks unusual, promptly make an appointment to see a dermatologist for evaluation. In general, annual skin exams with a dermatologist is recommended. This is especially important for adults who have risk factors for skin cancer, such as family history of skin cancer or have had lots of sun exposure.
Diagnosis:
The first step of diagnosing a melanoma will consist of obtaining a biopsy of the suspicious tissue and evaluating for the presence of cancer cells. Once the diagnosis and type of melanoma is confirmed, additional tests may be conducted to determine the stage of the disease. This workup may include blood work and imaging.
Melanoma staging consists of several factors, including depth of tumor penetration (known as Breslow depth), degree of tumor ulceration, spread to nearby lymph nodes, and metastasis (or spread) to distant lymph nodes or other organs. Once these characteristics have been identified, an overall stage number is assigned to your melanoma.
- Stage 0 and 1 consists of early melanomas that are localized and have not spread.
- Stage 2 consists of intermediate to high-risk melanomas that are >1 mm in Breslow depth. You may need a sentinel lymph node biopsy to assess whether the melanoma has spread to local lymph nodes.
- Stage 3 consists of melanomas that have already began spreading through lymph vessels or melanomas that have already reached local lymph nodes. Enlarged, palpable lymph nodes may be a sign of lymph node involvement.
- Stage 4 consists of melanomas that have spread to distant body sites, including lymph nodes, liver, lungs, brain, and other organ systems.
Treatment:
Treatment will depend on many factors including melanoma staging and condition of your health. Options can include surgical removal, chemotherapy, radiation, immunotherapy, and targeted therapy. Your dermatologist will review the risk and benefits of each approach and help you decide which one is best for you.
Sources:
Melanoma. American Academy of Dermatology Association 2022.
Melanoma Overview. Skin Cancer Foundation 2022.