Malignant Melanoma Staging

The American Joint Committee on Cancer (AJCC) tumor/node/metastasis (TNM) classification and staging system for cutaneous melanoma are provided below. ^{[1, 2]}  

Table 1. TNM Classification for Malignant Melanoma (Open Table in a new window)

Anatomic stage/prognostic groups

Table 2. Clinical staging (Open Table in a new window)

Table 3. Pathologic staging (Open Table in a new window)

Stage IA:

• Lesions ≤1 mm in thickness with no evidence of ulceration or metastases (T1aN0M0) are associated with a 5-y survival rate of ~97%

Stage IB:

• Lesions ≤1 mm in thickness with ulceration noted but without lymph node involvement (T1bN0M0) or lesions 1.01-2 mm in thickness without ulceration or lymph node involvement (T2aN0M0) are associated with a 5-y survival rate of ~92%

Stage IIA:

• Melanomas >1 mm but ≤2 mm in thickness with no evidence of metastases but with evidence of ulceration (T2bN0M0) or lesions 2.01-4.0 mm in thickness without ulceration or lymph node involvement (T3aN0M0) are associated with an overall 5-y survival rate of ~81%

Stage IIB:

• Melanomas 2.01-4 mm in thickness with ulceration but no lymph node involvement (T3bN0M0) or lesions >4 mm in thickness without ulceration or lymph node involvement (T4aN0M0) are associated with a 5-y survival rate of ~70%

Stage IIC:

• Lesions >4 mm in thickness with ulceration but no lymph node involvement (T4bN0M0) are associated with a 5-y survival rate of ~53%

Stage IIIA:

• Patients with any-depth lesion, no ulceration, and 1 positive (micrometastatic) lymph node (T1-4aN1aM0) have a 5-y survival rate of ~70%

• T1-4aN2aM0 lesions (any-depth lesion, no ulceration, but 2-3 nodes positive for micrometastasis) are associated with a 5-y survival rate of 63%

Stage IIIB:

• Patients with any-depth lesion, positive ulceration, and 1 lymph node positive for micrometastasis (T1-4bN1aM0) or 2-3 nodes positive for micrometastasis (T1-4bN2aM0) have a 5-y survival rate of 50-53%

• Patients with any-depth lesion, no ulceration, and 1 lymph node positive for macrometastasis (T1-4a, N1b, M0) or 2-3 nodes positive for macrometastasis (T1-4aN2bM0) have a 5-y survival rate of 46-59%

Stage IIIC:

• Patients with any-depth lesion, positive ulceration, and 1 lymph node positive for macrometastasis (T1-4bN1bM0); 2-3 nodes positive for macrometastasis (T1-4bN2bM0); or ≥4 metastatic lymph nodes, matted lymph nodes, or in-transit met(s)/satellite(s) have a 5-y survival rate of ~40%

Stage IV:

• Melanoma metastatic to skin, subcutaneous tissue, or lymph nodes with normal LDH level (M1a) is associated with a 5-y survival rate of ~15%-20%

• M1b disease (metastatic disease to lungs with normal LDH level) has a 5-y survival rate of 7%

• M1c disease (metastatic disease to all other visceral organs and normal LDH level or any distant disease with elevated LDH level) is associated with a 5-y survival rate of 10%

Mitotic rate assessment

For mitotic rate assessment, the pathologist counts the number of cells in a certain amount of melanoma tissue that are in the process of dividing. A higher mitotic rate means that the cancer is more likely to grow and spread. The mitotic rate is used to stage thin melanoma.