Staging is commonly used in melanoma diagnosis and treatment to indicate the advancement and severity and cancer in a patient. Melanoma stages range between 0-IV based on the TNM (tumour, nodes, metastasis) system. The TNM system is dictated by the size of the primary (first) tumour, the occurrence of cancer cells in the surrounding lymph nodes, whether the cancer has metastasized (spread to other regions in the body), and whether there is ulceration (if there is ulceration, the skin covering the melanoma cannot clearly be seen). While these figures can be intimidating in the later stages, the staging system is imperative for dictating the treatment process a patient will undergo.

Stage 0 is thin melanoma which has not penetrated (invaded) the deeper layers of the skin (in situ).

Stages I and II are melanomas that are limited to the skin. These melanomas vary in how thick they are and whether the skin covering the melanoma is ulcerated or not. Thicker melanomas and ulcerated melanomas have a higher risk of recurring.

Stage III is melanoma that has spread from the original site of your melanoma to 1 or more of the nearby lymph nodes or to the nearby skin/tissue in between. Stage III melanoma is divided into 4 groups, A, B, C, and D.

Stage IV is melanoma that has spread farther than regional lymph nodes, to distant sites such as the lung, liver, or brain.

To read more about the new (January 2018) 8th Edition AJCC Melanoma Staging System click here:

About Melanoma


While staging is clearly a complicated process with many variables, it is important to understand why a particular cancer case has been given its stage, and what that means for the future treatment of that patient.

Thank you for reading, and we hope this answers some of your questions about melanoma staging! For more information, take a look at our sources below. Be aware that while we write our blogs from a Canadian perspective, not every source we utilize is Canadian.


Works Cited Above:

Melanoma Staging”. NCCN Guidelines for Patients: Melanoma. 2014: National Comprehensive Cancer Network Foundation.

Canadian Cancer Society, “Stages of Melanoma“.