Overall, melanoma occurs less commonly than basal cell and squamous cell carcinomas. However, it is the most common form of cancer among young adults ages 25 to 29, with the incidence in young women rising. It is also the most life-threatening type of skin cancer. Early detection of melanoma is critical as it can spread rapidly through the lymph system and also to internal organs, making melanoma much more serious than non-melanoma skin cancers.
The Dermatological Center for Skin Health is staffed by dedicated professionals who are committed to providing truly collaborative care.
How melanoma is formed
Melanocytes are cells found in the bottom layer of the epidermis. These cells produce melanin, the substance responsible for skin pigmentation. That’s why melanomas often present as dark brown or black spots on the skin. Melanomas may also look like moles or can arise from existing moles. It is important for you to conduct regular self-examinations of your skin in order to detect any potential skin cancer early, when it’s more easily treated.
Most melanomas are caused by overexposure to the sun beginning in childhood. However, inherited gene mutations can lead to a much higher risk of developing melanoma. Some melanomas occur in sites with minimal sun exposure.
Early detection and diagnosis
Advances in early detection and diagnosis of melanoma is leading to earlier treatment and an increase in overall survival rates. If you’ve been identified as being at a higher risk for a melanoma diagnosis because you have light skin and greater sensitivity to the sun, have multiple atypical nevi or moles, large congenital moles, a family history of melanoma, or a history of blistering sunburns, we can help.
Melanoma is predominantly a disease of Caucasians, and is slightly more common in men than women. Primary lesions occur most commonly on the trunk in males, while melanomas in females occur most commonly on the lower extremities.
Where melanoma begins
Cutaneous melanomas usually begin in cells known as the epidermal melanocyte. Features that should increase suspicion of melanoma include:
Lesion asymmetry or border irregularity on moles
Bleeding or crusting
Recent changes in moles
Variation of color on existing moles (though some are non-pigmented)
Diameter over 6 millimeters
Development of an elevated area (when a flat lesion becomes raised)
Melanomas may be discovered when they are still in situ — meaning they are still “in the site” where their cell of origin, the melanocyte normally resides, staying in only the top layer of the skin — the epidermis. Melanomas which have breached beneath the top layer are invasive. Invasive melanomas are more serious, as they have penetrated deeper into the skin and may have spread to other areas of the body.
The stage of disease describes how advanced disease has become. Melanoma stages I and II are localized, and more stages III and IV have spread (metastasized) to other parts of the body. There are also subdivisions within stages.
If the disease has advanced to Stage IV, the melanoma cells have traveled through the body via the bloodstream or lymph vessels and have settled into another distant area of the body, likely far from the original tumor site. These cells may have reached distant lymph nodes or invaded the internal organs. This can be in addition to or instead of in-transit metastases or local spread to the regional lymph nodes. When it spreads locally, the melanoma can travel to skin or subcutaneous tissue more than 2 cm from the primary tumor, but not beyond the regional lymph nodes.
What are the risk factors for developing a melanoma?
Anything that increases your chance of getting melanoma is considered a risk factor. Sun damage, especially a history of blistering sunburns, is a risk factor for melanoma. Ultraviolet light is a known risk factor for skin cancer. There is no evidence that UV exposure from any type of tanning bed is less harmful than UV exposure from the sun.
Other risk factors for melanoma include:
Fair complexion: People with blond or red hair, light skin, blue eyes and a tendency to sunburn are at increased risk
A large amount of benign (non-cancerous) moles
Family history of melanoma
Atypical mole and melanoma syndrome (AMS)
If you have AMS, you and your family members should be screened regularly
Not everyone with risk factors gets melanoma. Ask yourself these questions:
What is a person's risk if melanoma runs in the family?
If a person has a first-degree relative with melanoma, his or her risk of developing melanoma is two to three times greater than the average risk. The risk is higher if several family members that live in different locations have been diagnosed with melanoma.
Which inherited genetic mutations raise the risk of melanoma?
There are several genes thought to be associated with an increased risk of melanoma. However, research to better understand how these genes affect the risk of melanoma is ongoing.
Familial malignant melanoma. There are at least three different genes have been linked to hereditary melanoma. Families with mutations in these genes may have multiple dysplastic nevi (flat moles that are irregular in shape or color). Although dysplastic nevi are likely to be related to altered genes, the specific genes involved have not been identified. The association of familial melanoma and multiple dysplastic nevi is also sometimes called familial atypical multiple mole melanoma (FAMMM) or atypical nevus syndrome. Families with inherited melanoma may also have an increased risk of developing pancreatic cancer and possibly other cancers.
Melanoma-astrocytoma syndrome. People with this rare condition have an increased risk of melanoma and astrocytoma (a type of brain tumor). The specific gene for this condition is thought to be located on chromosome 9. Families with both melanoma and astrocytoma have been shown to have changes in a gene called CDKN2A gene, which affects tumor growth.
Are there other genetic conditions associated with an increased risk of melanoma?
Other genetic conditions that are associated with an increased risk of melanoma include:
Xeroderma pigmentosum. Xeroderma pigmentosum (XP) is a group of rare conditions that makes a person's cells unable to repair DNA damage caused by ultraviolet (UV) light exposure, such as sunshine. Signs of XP are caused by the increased sensitivity to UV light, and include dry skin, abnormal pigmentation, severe freckling, and blistering after minimal sun exposure. People with this condition have a high risk of skin cancer, including melanoma (more than a thousand times more likely than the general population), and noncancerous skin abnormalities. People with XP also have an increased risk of other types of cancers including leukemia, brain tumors, stomach cancer, lung cancer, breast cancer, uterine cancer, and testicular cancer.
Retinoblastoma. Retinoblastoma is a childhood eye tumor. Children with hereditary retinoblastoma have an increased risk of developing other cancers as they grow older, especially melanoma (50 times more likely than the general population). They also have a higher risk for osteosarcoma (a type of bone cancer).
Early and accurate diagnosis is important in melanoma care. This helps us to know if the cancer has spread so we can choose the most effective treatment.
The Dermatological Center for Skin Health works closely with John Wayne Cancer Institute, seeking to improve diagnosis and develop tests to improve the accuracy of determining prognosis. The surgical oncology team uses the most modern and accurate technology to detect if melanoma and has spread. This helps increase the likelihood that your treatment will be successful. The Saint John's team includes pathologists and diagnostic radiologists who are highly skilled in diagnosing and detecting melanoma.
If you have signs or symptoms that may signal melanoma, your doctor will examine you and ask you questions about your health, your lifestyle and your family history. If melanoma is suspected, a biopsy will be done.
Skin cancer can't be diagnosed just by looking at it. If a mole or pigmented area of the skin changes or looks abnormal, a doctor may biopsy the mark, taking a tissue sample for a pathologist to examine. Suspicious areas should not simply be shaved off or destroyed with a hot instrument, an electrical current or a caustic substance. The tissue should be biopsied and sent for examination under the microscope to determine if the area is malignant before it is simply destroyed.
Local excision/excisional biopsy
The entire suspicious area is removed with a scalpel under local anesthetic. This is usually done as an outpatient procedure.
The doctor uses a tool to punch through the suspicious area and remove a round cylinder of tissue.
The doctor shaves off a piece of the growth and checked for any abnormal results.
Abnormal results may include:
Benign (non-cancerous) growths such as moles, warts and benign skin tumors
There are also tests for determining if melanoma has metastasized.
Your blood may be tested to help determine if the cancer has spread. For melanoma, this may include a complete blood count and chemistry panel, which is a test that evaluates blood electrolytes like potassium and calcium and enzymes or specialized proteins that can be abnormal if the melamona has metastasized. Your level of lactate dehydrogenase (LDH; an enzyme that can help signal tissue damage) may also be checked since it is a tumor marker. When elevated it can signal that the disease has reached an advanced stage.
An x-ray can show us the inside of your body, using a small amount of radiation, to help determine if there is any evidence of the spread of cancer to other organs.
An ultrasound uses sound waves to create pictures of the internal organs, including collections of lymph nodes and soft tissue.
Computed tomography (CT or CAT) scan
A CT scan creates a three-dimensional picture of the inside of the body with an x-ray machine. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. Sometimes, a special dye is injected into a patient's vein to provide better detail.
Magnetic resonance imaging (MRI)
An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. A contrast medium may be injected into a patient's vein to create a clearer picture.
Positron emission tomography (PET) scan
A PET scan is a way to create pictures of organs and tissues inside the body. A small amount of a radioactive substance is injected into the patient's body. This substance is absorbed mainly by the organs and tissues that use the most energy. Because cancer tends to use energy actively, it absorbs more of the radioactive substance. A scanner then detects this substance to produce images of the inside of the body.
How is melanoma staged?
If you are diagnosed with melanoma, your doctors will determine the stage (or extent) of the disease. Staging is a way of determining how much disease is in the body and where it has spread. This information is important because it helps our team determine the best type of treatment for you and the outlook for your prognosis.
Melanoma staging is based on:
Location(s) of the melanoma
Melanoma tumor thickness as well as other microscopic features
If melanoma has spread to nearby lymph nodes, and if so, how many and what size
If it has metastasized to other parts of the body
A blood test called lactate dehydrogenase (LDH) for stage IV melanoma
Stages I and II are based mainly on the thickness of the primary melanoma and other microscopic features.
Stages III and IV are based on how far the melanoma has spread from the skin; stage III signifies regional spread and stage IV is based on distant spread.
Stage 0 (Melanoma in situ):
Does not reach below the surface of the skin
Tumor thickness is not recorded for melanoma in situ
Stage IA: Melanoma:
Is less than 1 millimeter thick
Has less than 1 mitosis (dividing cell) per square millimeter
Stage IB: Melanoma:
Is less than 1 millimeter thick and with ulceration and/or has at least 1 mitosis (dividing cell) per square millimeter or 1 to 2 millimeters thick without ulceration
Stage IIA: Melanoma is either:
1 to 2 millimeters thick with ulceration or
2 to 4 millimeters thick with no ulceration
Stage IIB: Melanoma is either:
2 to 4 millimeters thick with ulceration or
More than 4 millimeters thick without ulceration
Melanoma is more than 4 millimeters thick with ulceration
Stage III: Melanoma:
Has spread through the lymph system (satellites and/or in-transit metastasis) or directly into the regional lymph nodes (lymph nodes that receive lymph drainage from primary tumor site)
Has not spread to distant organs
Melanoma has spread, or metastasized, to more distant lymph nodes and/or to other distant organs.