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While it is not the most common type of skin cancer, melanoma can prove to be one of the most dangerous forms. Over 87,000 people will likely receive a melanoma diagnosis in 2017, and nearly 10,000 will die from the disease.
“Malignant melanoma develops in melanocyte cells, which form melanin, a dark pigment in the skin,” explains Dr. Adam Mamelak, board certified dermatologist and Mohs micrographic surgeon at Sanova Dermatology. Tumors usually form on exposed skin, the chest, back, and legs, though it can form on the eyes, lips and mouth, or other delicate areas of the body. These skin cancers often appear dark because of the melanin.
Several factors can cause melanoma, including exposure to dangerous UV (ultraviolet) rays from the sun or a mole may turn cancerous. A person’s risk of developing melanoma increases with age, as they have greater exposure to the sun over time.
If you suspect you may have melanoma on your skin, or a mole just doesn’t quite look the same as it used to, do not delay in seeking treatment. Your dermatologist will take a biopsy to determine if the growth is cancerous and will expedite treatment if the results return positive.
Melanoma can spread rapidly, so it’s important to have an understanding of how it develops and the growth cycle it follows. “Your pathology report, the analysis of your biopsy, will indicate your melanoma’s current stage of growth and give you and your doctor helpful information as to the most appropriate course of treatment, depending on how advanced your tumor is,” explains Dr. Mamelak.
The American Joint Committee on Cancer (AJCC) has developed a staging system for melanoma based on a tumor’s thickness, size, and whether or not it has metastasized — a system known as Tumor-Node-Metastasis, or TNM.
If you’re diagnosed with melanoma, your doctor will need to determine the thickness of your tumor and assess whether or not it has begun to spread to other parts of the body, particularly your lymph nodes or blood vessels.
A function known as Breslow’s depth provides doctors with an indication of your tumor’s thickness. Similarly, the Clark’s level provides a way to assess which layers of skin your tumor has spread to. A high Clark’s level generally indicates a deep tumor, but it does not necessarily indicate your likely prognosis, as Clark’s level does not reflect the stage of melanoma
Melanoma skin cancer tends to grow in two fashions: radiating outwards across the surface of the skin and vertically downward into the skin. During the radial growth phase, cancer cells spread laterally across your skin. While your tumor may still have grown over time, it has not necessarily spread to other organs yet, as its movement remains horizontal across the same layer of skin.
“It’s during the vertical growth phase, however, we think these melanoma skin cancers develop a propensity to spread,” says Dr. Mamelak. During this phase, cells begin to divide in the dermis, which lies deeper in the skin and contains sweat glands, blood and lymphatic vessels. Tumors that have reached the vertical growth phase can prove aggressive and may metastasize quickly, if they have not already.
Your doctor will monitor whether or not your cancer has metastasized, or spread to the lymph nodes, a process known as lymphatic spread. In some cases, doctors can remove the affected lymph node, or lymph nodes, before the cancer spreads to far. A patient may also experience hematogenous spread, when the cancer spreads to the bloodstream.
Melanoma may also be classified in terms of contiguous growth, where tumor cells locally invade organs or tissues that are directly next to or touching the skin cancer, or non-contiguous growth, where the cancer cells break off and spread to other parts of the skin or body that do not directly touch the original tumor.
It’s important to identify and treat melanoma early to improve your prognosis. Several surgical procedures and medical therapies offer good treatment options to both remove the tumor and treat it. If you suspect you may have melanoma, or you would like more information about how the disease progresses, please contact us to discuss your treatment options.