Skin Cancer Diagnosis

If your physician suspects that a mark on the skin is melanoma, you will need to have a biopsy to make a definite diagnosis. This procedure is called an excisional biopsy or wide local excision. If the growth is too large to be removed entirely, your physician will remove a sample of the tissue with a punch biopsy or incisional biopsy.

A biopsy usually can be done in the physician's office using local anesthesia. A pathologist then examines the tissue under a microscope to look for cancer cells.

If cancer is detected The prognosis from melanoma depends on the stage at which it is diagnosed. Cancer is staged using the numbers 0 through IV (see more about cancer staging at cancerstaging.org). There are several important factors that determine the prognosis from melanoma:

• Breslow Thickness: The thickness of the melanoma, measured by the pathologist in millimeters, is a very important factor. In general, thin melanomas (1 mm thickness) have an excellent prognosis. Melanomas >4 mm are serious melanomas with a significant chance of spreading to other parts of the body. Melanomas between 1 and 4 mm are called "intermediate thickness" melanomas, with an intermediate chance of spreading to lymph nodes or elsewhere.

  

• Clark's Level: This is a measure of the level of invasion of the melanoma into the skin, graded from I to V. In general, it is not as helpful or accurate as the Breslow thickness. Many patients focus on the Clark's level of invasion because it is a number they can easily remember. Many Clark's level IV melanomas, however, have a very good prognosis.

• Lymph Nodes Status: Whether or not the cancer has spread to the regional lymph nodes (usually in the neck, under the arm, or in the groin) is the single most important factor predicting survival.

  

• Ulceration: Ulceration is defined by the pathologist as the absence of an intact epithelium overlying the melanoma. It turns out that ulceration is a very important factor, and if present, indicates a worse prognosis.

The Staging System

Stage 0: The melanoma cells are found only in the outer layer of skin cells and have not invaded deeper tissues. This is called melanoma-in-situ. In situ means that the melanoma has not invaded to the point that it could spread to lymph nodes or other places. Melanoma-in-situ is not really invasive cancer-it is pre-cancerous.

Stage I: The melanoma is thin and has not spread to nearby lymph nodes. It is considered thin if:

• The tumor is no more than 1 millimeter (1/25 inch) thick. The outer layer (epidermis) of skin may have an ulceration, which means it appears scraped; or
• The tumor is between 1 and 2 millimeters (1/12 inch) thick with no ulceration.

Stage II: The melanoma is at least 1 millimeter thick and has not spread to nearby lymph nodes. It is considered Stage II if:

• The tumor is between 1 and 2 millimeters thick. There is ulceration; or
• The thickness of the tumor is more than 2 millimeters. There may be ulceration.

Stage III: Melanoma cells have spread to one or more nearby lymph nodes.

Stage IV: The melanoma cells have spread to other organs, to lymph nodes or to skin areas far away from the original tumor.

Melanoma is considered recurrent when the cancer has returned after it has been treated. It may have come back in the original site or in another part of the body.