The only way to definitively diagnose the various types of skin cancer is to biopsy suspicious-looking lesions. Useful information, such as tumor depth, can only be obtained by biopsy. Biopsy methods include:
- Shave biopsy: During this procedure the doctor uses a thin, sharp blade to shave off the abnormal growth. This is the most common form of biopsy when the doctor suspects a basal cell carcinoma or squamous cell carcinoma.
- Punch biopsy: A punch biopsy is when a sharp, hollow tool is used to remove a circle of tissue from the abnormal area.
- Incisional biopsy: This procedure is performed using a scalpel to remove part of the growth.
- Excisional biopsy: During this procedure, your doctor uses a scalpel to remove the entire growth and some tissue around it. Excisional biopsy is the ideal choice when a doctor suspects a melanoma. However, depending on the size or location of the tumor, an excisional biopsy may not always be possible.
If the biopsy indicates you have melanoma, your doctor needs to know the extent (stage) of the disease to select the best treatment plan for you. The staging of skin cancer is based on these three factors:
- The size of the growth
- How deeply it has grown beneath the top layer of skin
- Whether it has spread to nearby lymph nodes or to other parts of the body
The stages of melanoma are as follows:
- Stage 0: The cancer involves only the top layer of skin. It is called melanoma in situ.
- Stage I: The growth is less than two millimeters deep.
- Stage II: The growth is more than two millimeters deep.
- Stage III: The cancer has spread below the skin to cartilage, muscle, bone or to nearby lymph nodes. It has not spread to other places in the body.
- Stage IV: The cancer has spread to other places in the body.