It is important to determine the exact stage of the disease to be able to accurately determine further treatment. When the melanoma is detected in its earlier stages, there is a better survival rate.
The stage is determined on the basis of clinical, histopathologic findings and additional diagnostic results that are required in order to determine the expansion of melanoma to lymph nodes and other organs.
Stages are determined on the basis of TNM classifications of the AJCC (American Joint Committee on Cancer) where T indicates the size of the tumour, N indicates the involvement of lymph nodes, and M indicates the existence of metastasis.
For this stage the term "melanoma in situ" is sometimes used. A melanoma, which was discovered at this stage, is in the superficial area of the skin (the epidermis) and has not spread to the dermis of the skin. Lymph nodes are not affected and there are no distant metastases.
Stage I is divided into two subgroups: IA and IB, depending on the thickness of the melanoma (< 0.8 mm, 0.8 – 1.0 mm, > 1.0 – 2.0 mm) with or without ulceration. Lymph nodes are not affected and there are no distant metastases.
Stage II is divided into three subgroups A, B and C with respect to thickness and the existence ulceration, but has not expanded to the lymph, lymph nodes or distant organs.
Stage III – a melanoma which can be various thicknesses, but it is expanded through the lymph into the lymph nodes, or in the skin areas in the immediate vicinity. A small melanoma in the vicinity of the primary melanoma is referred to as a satellite melanoma.
Stage IV indicates a melanoma that has spread to distant parts of the body. It may expand to distant organs such as the brain, lungs, liver and in the bone or in distant parts of the skin.
The stage in which a melanoma is discovered affects the average survival rate of patients with melanoma. The earlier the melanoma is detected, the survival rate is higher, and thus the survival rate for early detected melanoma, for example, in stage IA is around 97%. If the tumour is detected in stage IV, then the survival rate is 15 to 20%.
Monitoring (follow-up) of patients, or the frequency of control examinations, depends on the stage of the disease. Monitoring includes a dermatological, clinical and dermoscopic examination, laboratory tests (including LDH), abdominal ultrasound, postoperative scarring and regional lymph nodes, and in higher stages, CT and PET/CT scans.