Melanoma is removed surgically by excision, which means cutting it out. The goal is to remove all of the melanoma cancer cells. This is often done as two procedures.
- The first procedure is a diagnostic excision.
- The second procedure is the re-excision, also called wide local excision.
Diagnostic excision removes the cancer
If your doctor suspects a skin spot is a melanoma, it is cut out with a small margin (usually about 2 mm) of normal skin surrounding it. This may be done by your family doctor, or you may be referred to another doctor for the procedure. This is called a diagnostic excision. The cut-out tissue is sent to a pathology lab for testing.
Re-excision ensures none is left behind
If the pathology report is positive for melanoma, a second procedure usually takes place a few weeks later. This is to make sure the melanoma has been completely removed and includes removing a larger margin of normal tissue.
The size of the re-excision margin depends on the Breslow thickness measured by the pathologist and the site of the melanoma. Sometimes it is difficult to achieve recommended margins in sites such as the mid-face.
Re-excision may be done by your family doctor if the melanoma is in situ (Stage 0) or thin and less than 1 mm in thickness (Stage IA). Otherwise, you will be referred to a dermatologist or a surgical specialist for further management.
How much skin will be removed when I have the re-excision?
The re-excision will remove the wound or scar from the diagnostic excision, with a margin of normal skin measured at the time of surgery, as shown in the table below.
|Breslow thickness||Size of margin|
|Melanoma in situ||5–10 mm|
|Melanoma < 1 mm||10 mm|
|Melanoma 1–2 mm||10–20 mm|
|Melanoma > 2 mm||> 20 mm|
Tell me more about the surgery
Simple excision and repair
In most cases, melanoma is cut out by simple excision.
- A local anaesthetic injection is given to numb the skin that is to be removed.
- The doctor will cut around and under the melanoma with a scalpel. As described above, a margin of normal skin tissue surrounding the melanoma will also be cut out.
- There might be some bleeding in the area, and the doctor may use a tool to burn and seal off the wound (electrocautery).
- The edges of the wound are sewn together to make a thin line of stitches (sutures).
- A dressing will be applied.
- You will be told how to care for your wound and when to get the stitches out.
Excision with complex repair
Some large wounds cannot be repaired by simply drawing the edges together and stitching them up. In these cases, the defect may require a skin flap or skin graft. Your doctor will explain the procedure to you.
Mohs micrographic surgery
- A local anaesthetic injection is given to numb the skin around the melanoma.
- The visible melanoma is removed in the normal way and sent to the pathology laboratory for standard processing.
- The dermatologist then takes horizontal sections (layers of skin tissue) surrounding the wound and examines them under the microscope. If cancer cells are found then another layer of tissue is cut out and checked. This continues layer by layer until there is no sign of cancer cells remaining in the skin.
- Depending on the size of the wound it may be closed with stitches, or reconstructed with a skin graft or flap.
- Mohs surgery usually takes about 3 hours, but in some cases, if the tumour is large, it can take a whole day or longer.