Melanocytes are the cells that produce the pigment responsible for the color of your skin and cancer arising from these cells is called Melanoma. Melanoma is more rare than basal cell and squamous cell skin cancer and is considered a more dangerous type of skin cancer as it has a higher risk of spreading to lymph nodes or remote parts of the body. Melanoma can develop from a pre-existing mole or can appear as a new pigmented spot in the skin. Most melanomas are shades of brown or black but some can appear as lighter colors.
Risk Factors: There are several risk factors that increase your risk for melanoma
- Light or fair skin and light hair color
- Genetics/family history: those with a family history of melanoma are more likely to develop melanoma
- Having many moles [nevi] on the skin: Having many moles increases your risk as these moles have the ability to become melanoma. However, most moles never become melanoma.
- Ultraviolet [UV] rays are also linked to melanoma and therefore a history of severe childhood sunburns or increased sun exposure can increase the risk of melanoma.
Diagnosis and Workup: Diagnosing and treating melanoma early and accurately increases the probability of successful treatment. If you have risk factors for melanoma, you should seek a skin exam by a health care professional, but you should also frequently examine your own skin. Knowing if there is a change to a mole is very important information in the diagnosis of melanoma. When looking for melanoma, the following worrisome features can be remembered using the melanoma “ABCDE’s”:
A is for Asymmetry: look for an irregular shape or two halves of the lesion that are differently shaped
B is for Border: look for irregular borders that are not smooth
C is for Color: look for different colors within the pigmented spot or different shades of color
D is for Diameter: diameter larger than 6 millimeters or a quarter of an inch is concerning
E is for Evolving: look for growths that are changing in size, color or shape. Bleeding or itching are also concerning signs
Workup for melanoma starts with a whole body skin exam and lymph node exam and a skin biopsy. The biopsy material may be tested for gene mutations, such as mutation in a gene called “BRAF”.Melanomas with BRAF mutations may respond to certain drugs designed to specifically block the BRAF gene pathway. Early stage melanoma often does not require imaging tests but more advanced melanoma will require imaging in the form of a PET scan, an MRI and/or CT scan. Sentinel lymph node biopsy is also recommended for melanoma that is close to or more than 1 mm in thickness. Sentinel lymph node biopsy uses a special injection and imaging to find lymph nodes near the melanoma, where the melanoma cells could potentially travel. [link to SLNBx] The thickness of the melanoma is determined by the skin biopsy.
Staging: Staging is a process to categorize the cancer by how big it has grown and how far it has spread For melanoma, the depth of the tumor and presence of ulceration is important for staging.
- Stage 1: The tumor has a depth of 1.0 mm or less with or without ulceration or is between 1.1-2.0mm without ulceration and has not spread to lymph nodes or other organs
- Stage 2: The tumor is between 1.1-2.0mm with ulceration or greater than 2.0mm with or without ulceration and has not spread to lymph nodes or other organs.
- Stage 3: The tumor has spread to nearby lymph nodes or through lymph channels to separate areas of the skin but has not spread to distant organs
- Stage 4: The tumor has spread to distant areas such as the lungs or brain
Treatment and Outcomes: Treatment of melanoma is generally surgery [WLE link] to remove the melanoma along with a rim of normal tissue around it. The width of this rim is determined by the depth of the melanoma and any other high-risk features. If the sentinel lymph node biopsy [SLNBx link] was done and showed cancer in the lymph node, removal of the lymph nodes from the neck, also called a neck lymph node dissection or “Neck dissection” [neck dissection link] with or without removal of lymph nodes from the large saliva gland overlying the jaw, also called a “parotidectomy” [parotidectomy link] may be considered. Removing the lymph nodes decreases the chance of the melanoma coming back in the head and neck area which is dangerous to all the important structures in the head and neck. After surgery, radiation and/or adjuvant chemotherapy be recommended.
Surveillance and Survivorship: Once you have developed a melanoma, there is a risk the melanoma can come back in the same area, in lymph nodes or other areas of the body. As time goes on, this becomes less likely, but a small risk persists. You are also at increased risk of developing another melanoma. In order to decrease the risk of melanoma, it is important to avoid and/or cover up from the sun, use sunscreen when outside, and avoid tanning beds and UV lamps.
Article by Alice Lin, MD