Stages of Melanoma

Melanoma, the most serious type of skin cancer, develops in the cells (melanocytes) that produce melanin — the pigment that gives your skin its color. Melanoma can occur anywhere on the skin, and people with unusual moles, a family history of skin cancer, or repeated exposure to sunlight are at the highest risk.

Melanoma can most easily be identified by a change in the way that a mole or pigmented area looks — especially if it changes shape, size, or becomes painful, tender, itchy or begins to bleed.

Melanomas are classified into stages 0-IV, with 0 being the least invasive and IV being the most, usually meaning the cancer has metastasized, or spread, to other parts of the body. Melanomas are categorized into their stages by how thick or deep the tumor is, where the melanoma is located, whether it has spread to the lymph nodes, and whether it has metastasized to other parts of the body.

Stage 0

A Stage 0 tumor, also referred to as in situ, only affects the outermost layer of skin, or the epidermis. Stage 0 melanoma is localized and unlikely to spread to other parts of the body.

Stage I

Stage 1 melanoma is usually very thin and has only affected the next layer of skin below the epidermis, the dermis.

Stage II

A stage II tumor is considered medium-risk, but is still localized and penetrates further into the dermis. It is larger than stage I — usually a thickness of 1mm or greater. Stage II cells may also have traits that could indicate risk of spreading to nearby lymph nodes such as ulcerations.

Stage III

Stage III is considered high-risk and has spread locally or to a regional lymph node located near where the cancer started. Stage III tumors are classified into subgroups A, B, C, or D based on the size and number of lymph nodes involved.

Stage IV

Stage IV is the most serious stage of skin cancer and has traveled through the bloodstream to other parts of the body like other locations on the skin, distant lymph nodes, bones, or other organs such as lungs, the liver, or the gastrointestinal tract.

If you identify a spot on your skin that looks unusual, visit a dermatologist right away to have the area biopsied. Receiving a melanoma diagnosis can feel scary, but understanding the different classifications, or stages, of skin cancer can help determine the best treatment path forward.

Disclaimer: This blog provides general information and discussion about medical, cosmetic, mohs, and surgical dermatology. The words and other content provided in this blog, and in any linked materials, are not intended and should not be construed as medical advice. If the reader or any other person has a medical concern, he or she should consult with an appropriately-licensed dermatologist or other health care worker.