The National Cancer Institute says that each year in the United States, more than 58,000 people learn they have melanoma, the most dangerous type of skin cancer. Melanoma causes more than 8,000 deaths per year, according to the Merck Manual, and has a better prognosis if diagnosed before it spreads. Melanoma staging, which ranges from Stage 0 to Stage 4, describes the size and depth of the lesion and metastasis, if any. A biopsy removes cells for microscopic examination. Beginning stages of melanoma, before cancer spreads, include Stage 0, 1 and 2.
Stage 0
Staging for melanoma includes scoring for three factors, called TNM. T, for tumor, describes the depth or thickness of the cancer cells, labeled as 0 to 4. N stands for "nearby," describing whether the tumor has spread to the lymph nodes, and M, which stands for metastasis, or whether the cancer cells have spread to distant sites, according to the American Cancer Society. Stage 0 melanoma is described as Tis, meaning in situ, or confined to the top layer of cells, N0, M0. The earliest stage of detectable melanoma, Stage 0 describes lesions that haven't spread beyond the epidermis, the most superficial layer of skin. The five-year survival rate for Stage 0 melanomas removed surgically is 100 percent, the Merck Manual reports. Stage 0 melanoma most likely won't recur, the Melanoma Center says.
Stage 1
Stage 1, further divided into Stage 1A and 1B, describes small melanomas with no ulceration. Stage 1 disease is less than 1mm, while Stage 2 disease may be less than 1mm with ulceration, or 1mm to 2mm without ulceration. Ulceration causes a scraped appearance to the skin, the National Cancer Institute reports, and is reported as A, for absent ulceration, and B for ulceration. Cancer has not spread to nearby lymph nodes. Survival rates are greater than 95 percent for 1A and 89 percent to 91 percent for 1B, Merck says.
Stage 2
In Stage 2A , ulceration is present and the tumor is between 1mm and 2mm with ulceration and between 2mm to 4mm without ulceration. For Stage 2B, melanoma measures between 2mm to 4mm with ulceration and over 4mm without. Survival rates for Stage 2A range from 77 percent to 79 percent, and survival rates for Stage 2B from 63 percent to 67 percent, Merck says. In Stage 2 disease, melanoma has not spread to the lymph nodes.
