Stages

Melanomas evolve from a highly-treatable superficial spreading cancer to a metastatic cancer afflicting the lymph nodes and vital organs. There are four primary stages of melanoma (I, II, III, and IV) and a higher number reflects a more advanced stage. There are many diagnostic and prognostic factors to consider in melanoma staging, but the international standard for staging melanoma is the American Joint Committee on Cancer's TNM Staging System. Within each of the four primary stages are more specific stages denoted by a single letter following the roman numeral. For example, one may have stage IIIA melanoma.

In cancer staging, there is clinical staging, and pathologic staging. These two different types of staging reflect the information considered for determining stage. A pathologic stage is more meaningful than a clinical stage because it draws a diagnosis based on more information than just that which is obtained during clinical staging. Clinical stage may be determined through the result of a biopsy of the primary tumor site, clinical/radiographic evaluation of lymph nodes, physical exams, and imaging tests (x-ray, CT Scan). Pathologic stage is determined through the clinical stage, a wide re-excision of the primary tumor site, and, if necessary, microscopic assessment of regional lymph nodes through sentinel lymph node (SNL) biopsy. Regional lymph nodes are an important part of melanoma staging because melanomas metastasize to regional lymph nodes before distant organs or lymph nodes.

TNM System

The TNM staging system as set forth by the American Joint Committee on Cancer (AJCC) describes cancers using three criteria: tumor thickness and ulceration, regional lymph node involvement, distant metastasis. A TNM stage assigned using clinically-obtained information is called a cTNM stage; likewise, a TNM stage assigned using pathologic evaluation is called a pTNM stage. It follows that a pTNM stage is more specific and meaningful than a cTNM stage. For each stage of melanoma, there is a specific set of corresponding pTNM stages, but cTNM stages as they correspond to melanoma stages are summarized in the following table:

Diagnostic/Prognostic Factors

Breslow Thickness

Breslow Thickness simply refers to the thickness (depth) of the primary melanoma tumor. Breslow Thickness is measured from the granular layer of skin to the deepest-found melanoma cells, and is recorded in millimeters.

Ulceration

Ulceration occurs when the epidermis of the primary tumor is not fully in-tact. This may present itself as a crater on the primary tumor. Ulceration, along with Breslow Thickness, define the "T" in a given TNM stage.

Mitotic Rate

Mitotic rate is not a "rate" in the word's traditional sense because mitotic rate does not include a notion of time. Rather, mitotic rate is the number of microscopically observable melanoma cell mitoses occurring at the time of primary tumor biopsy. Mitotic rate is not considered in TNM staging because it is not a consistently meaningful prognostic factor, though it may indicate risk for metastasis.

Clark Level

Clark Level, also known as level of invasion, is a system which describes how deeply melanoma cells have penetrated the skin. This system is not used in TNM staging, though it is similar to Breslow Thickness in the sense that it describes tumor depth. Clark Level is defined by the type of skin tissues melanoma cells are found in, rather than the millimeter thickness of the tumor. Studies found that Clark Level is a less accurate prognostic factor than Breslow Thickness, and this is why Breslow Thickness is used in TNM staging instead of Clark Level.

Clark Levels

Level I: Melanoma cells are confined to the epidermis (melanoma in-situ).

Level II: Melanoma cells invade but do not fill or expand the papillary (superficial) dermis.

Level III: Melanoma cells fill and expand the papillary dermis with extension of tumor to the papillary-reticular dermal interface.

Level IV: Melanoma cells infiltrate into the reticular dermis.

Level V: Melanoma cells infiltrate into the subcutaneous fat.

Stage 0 (in-situ)

The melanoma has not penetrated to the layers of skin beyond the epidermis (the top most skin), meaning that the cancer is only located at the visible lesion. Stage 0 melanomas are easily treatable and have a very high survival rate when properly treated. Surgically removing the melanoma and a small margin of surrounding healthy skin through a wide local excision is the most common and effective treatment for stage 0 melanomas. However, some dermatologists offer alternative non-invasive treatment options such as imiquimod cream (Zyclara).

Stage I

The melanoma is up to 2mm thick and has not metastasized to local lymph nodes or anywhere else in the body; however, Stage I melanomas may have ulceration. Melanoma ulceration is when part of the epidermis covering the cancerous lesion is not in tact. Ulceration is determined by a biopsy of the primary melanoma. There are two sub-classifications of stage I melanoma (stage IA and stage IB) which reflect different tumor depths and ulceration.

Stage IA

Primary tumor is less than 1.0mm thick, with or without ulceration.

SURVIVAL RATES FOR STAGE IA MELANOMA

5-year Survival Rate: 97% - 10-year Survival Rate: 95%

Stage IB

The melanoma is between 1.0 and 2.0mm thick without ulceration.

SURVIVAL RATES FOR STAGE IB MELANOMA

5-year Survival Rate: 92% - 10-year Survival Rate: 86%

Stage II

The melanoma is 1-4mm thick and has not metastasized to local lymph nodes or anywhere else in the body. Stage II melanomas may have ulceration. Melanoma ulceration is when part of the epidermis covering the cancerous lesion is not in tact. Ulceration is determined by a biopsy of the primary melanoma. There are three sub-classifications of stage II melanoma (stage IIA, IIB, and IIC) which reflect different tumor depths and ulceration.

Stage IIA

The primary tumor is between 1.0 and 2.0mm thick with ulceration, or the primary tumor is between 2.0 and 4.0mm without ulceration.

SURVIVAL RATES FOR STAGE IIA MELANOMA

5-year Survival Rate: 81% - 10-year Survival Rate: 67%

Stage IIB

The primary tumor is between 2.0 and 4.0mm thick with ulceration, or the primary tumor is thicker than 4.0mm without ulceration.

SURVIVAL RATES FOR STAGE IIB MELANOMA

5-year Survival Rate: 70% - 10-year Survival Rate: 57%

Stage IIC

Stage IIC melanomas are thicker than 4.0mm with ulceration.

SURVIVAL RATES FOR STAGE IIC MELANOMA

5-year Survival Rate: 53% - 10-year Survival Rate: 40%

Stage III

Stage III melanomas have lymph node involvement and are discovered through sentinel lymph node biopsies following a clinical diagnosis. Sentinel lymph node biopsies are recommended for patients with melanomas at least 1mm thick.

Stage IIIA

The primary tumor is either up to 1.0mm thick with or without ulceration, or between 1.0 and 2.0mm without ulceration. There is at least one, and up to three regional, clinically occult, tumor-involved lymph nodes. In other words, there are between 1 and 3 tumor-involved lymph nodes which can only be detected through pathologic means, such as sentinel lymph node biopsy.

SURVIVAL RATES FOR STAGE IIIA MELANOMA

5-year Survival Rate: 93% - 10-year Survival Rate: 88%

Stage IIIB

There is no evidence of a primary tumor, but one clinically detected tumor-involved lymph node, or no tumor-involved lymph nodes but the presence of in-transit, satellites, and/or microsatellite metastases.

The primary tumor is up to 1.0mm thick with our without ulceration, or between 1.0 and 2.0mm without ulceration, and either 1.) one clinically detected tumor-involved lymph node 2.) no tumor-involved lymph nodes but the presence of in-transit, satellites, and/or microsatellite metastases or 3.) either two or three tumor-involved lymph nodes, at least one of which was clinically detected.

The primary tumor is between 1.0 and 2.0mm thick with ulceration, or between 2.0 and 4.0mm without ulceration, and either 1.) one clinically occult tumor-involved lymph node (detected through pathologic means such as SNL biopsy) 2.) one clinically detected lymph node 3.) no tumor-involved lymph nodes but the presence of in-transit, satellites, and/or microsatellite metastases 4.) either two or three tumor-involved clinically occult lymph nodes or 5.) either two or three tumor-involved lymph nodes, at least one of which was clinically detected.

SURVIVAL RATES FOR STAGE IIIB MELANOMA

5-year Survival Rate: 83% - 10-year Survival Rate: 77%

Stage IIIC

There is no evidence of the primary tumor and either 1.) two or three tumor-involved lymph nodes, at least one of which was clinically detected 2.) one clinically occult or clinically detected tumor-involved lymph node and the presence of in-transit, satellite, and/or microsatellite metastases 3.) four or more tumor-involved lymph nodes, at least one of which was clinically detected, or the presence of any matted nodes 4.) two or more clinically occult or clinically detected tumor-involved lymph nodes and/or presence or any matted nodes, and the presence of in-transit, satellite, and/or microsatellite metastases.

The primary tumor is up to 2.0mm thick with or without ulceration, or the primary tumor is between 2.0 and 4.0mm without ulceration, and either 1.) one clinically occult or clinically detected tumor-involved lymph node and the presence of in-transit, satellite, and/or microsatellite metastases 2.) four or more clinically occult tumor-involved lymph nodes 3.) four or more tumor-involved lymph nodes, at least one of which was clinically detected, or the presence of any matted nodes 4.) two or more clinically occult or clinically detected tumor-involved lymph nodes and/or presence or any matted nodes, and the presence of in-transit, satellite, and/or microsatellite metastases.

The primary tumor is between 2.0 and 4.0mm thick with ulceration or the primary tumor is thicker than 4.0mm without ulceration, and any degree of lymph node involvement greater than the N1 classification (one tumor-involved lymph node, or in-transit, satellite, and/or microsatellite metastases with no tumor-involved nodes).

The primary tumor is thicker than 4.0mm with ulceration, and either 1.) one clinically occult tumor-involved lymph node (detected through pathologic means such as SNL biopsy) 2.) one clinically detected lymph node 3.) no tumor-involved lymph nodes but the presence of in-transit, satellites, and/or microsatellite metastases 4.) either two or three tumor-involved clinically occult lymph nodes or 5.) either two or three tumor-involved lymph nodes, at least one of which was clinically detected 6.) one clinically occult or clinically detected tumor-involved lymph node and the presence of in-transit, satellite, and/or microsatellite metastases.

SURVIVAL RATES FOR STAGE IIIC MELANOMA

5-year Survival Rate: 69% - 10-year Survival Rate: 60%

Stage IIID

The primary melanoma is thicker than 4mm with ulceration and either 1.) four or more clinically occult tumor-involved lymph nodes (detected through pathologic means such as SNL biopsy) 2.) four or more tumor-involved lymph nodes, at least one of which was clinically detected, or the presence of matted nodes 3.) two or more clinically occult or clinically detected tumor-involved lymph nodes and/or the presence of any matted nodes, and the presence of in-transit, satellite, and/or microsatellite metastases.

SURVIVAL RATES FOR STAGE IIID MELANOMA

5-year Survival Rate: 32% - 10-year Survival Rate: 24%

Stage IV

Stage IV melanoma has metastasized beyond the primary tumor and local lymph nodes to distant lymph nodes or organs (distant metastasis), including the liver, lungs, and central nervous system (CNS). The primary tumor may be of any thickness, and lymph node involvement may occur in the full spectrum of degrees; the defining characteristic of stage IV melanoma is the disease's metastasis to distant sites.

SURVIVAL RATES FOR STAGE IV MELANOMA

5-year Survival Rate: 15-20% - 10-year Survival Rate: 10-15%