What is Formal Surgical Excision?
A formal surgical excision is commonly performed in the skin cancer clinic as a way to both remove and treat a suspected lesion. Surgical Excision provides the best possible full-thickness skin sample for the pathologist to work with. This method is usually the best way to diagnose a suspected melanoma.
There are two main issues to consider:
- Is the objective to do a single curative procedure at the same time as confirming the diagnosis? Examples are removal of a BCC or SCC which are identified by dermatoscopy.
- Or is the objective to get a biopsy sample? Other methods of biopsy are punch biopsy and shave biopsy. It is generally recommended that pigmented skin lesions (possible melanoma) are biopsied with a formal surgical excision although there are places for both Punch Biopsy and Shave Excision.
The standard procedure is an elliptical or diamond shaped excision with variations on this theme. The procedure is a sterile procedure performed under local anaesthetic.
Lesions not suitable for ellipses are flaps and grafts which are carried out by different specialists (some skin cancer doctors or dermatologists, and most plastic surgeons).
How big will the scar be?
The question is really – what is the length of the scar? For a standard excision, imagine a circle drawn around the lesion. This circle must include a margin of normal skin either side of the lesion (the margin is usually 2-4mm but may be considerably greater). Now measure the width (diameter) across this circle and multiple this figure by 3 to get the approximate length of scar.
For example, consider a lesion measuring 8mm across that is removed with margins of an additional 2mm either side. The total width of the skin to be removed is 8mm (the lesion itself) + 2mm (margin of skin one side) + 2mm (margin of skin the other side) = a diameter of 12mm across. The length of the scar will be approximately 3 x the diameter. In this example, 3 x 12mm = approximately a 36mm length scar.
So you can see how a small lesion (8mm) leaves a much longer scar (around 3.5cm). This often comes as a surprise.
The scar may be a little shorter or longer depending on factors such as the movement of the skin.
What are the risks of surgical excision?
- Infection: around 5% but depends on a number of variables (age, medical problems, medications, type of procedure, climate – North Queensland has a significantly rate of wound infection)
- Bleeding: usually 20 minutes of firm pressure over an absorbent material will stop bleeding
- Wound deshiscence (the wound coming apart) eg following bleeding or infection
- Minor risks: swelling (seroma – clear fluid or ooze under the skin), suture allergy
- Rare risks: reaction or allergy to local anaesthetic (with or without adrenaline)
- Longer term risks: Hypertrophic scar is excessive but normal scar tissue. Keloid scar is scar tissue that continues to grow outside the wound edge. Keloid is most likely to occur on the front of chest, shoulders, ear lobes. Some people are genetically prone to keloid scarring. Keloid is more common in Asian, Black & Hispanic people.
What are the alternative treatments?
There are risks to everything medical (almost) – and doing nothing is rarely an option with skin cancer. However, there may other surgical or topical treatments that are appropriate, and these options should be discussed. However, it’s usually pretty clear when a skin cancer is is best removed in its entirety.
When are the stitches removed?
A rough guide only (it is an individual decision depending on factors such as ease of closure, age of patient & how physical the person will be afterwards)
- Face 5 days
- Scalp: 7 to 9 days
- Trunk & Back: 10 to 14 days
- Legs and feet: 14 days or longer
- upper limbs: 8 to 14 days
The face heals quickly and early removal of sutures will reduce risk of suture scars. The lower legs need the longest time before removal of suture because of the tension of the skin in that area and the movement to be expected with day to day activities.
How should I care for the wound?
The wound is only at 10% of final strength at 2 weeks, and 50% at 4 weeks. Healing wounds are delicate and need to be respected!
The key is to keep it covered until the removal of the sutures. It’s proven that moist wounds heal faster and better than dry wounds. The old adage of “getting air to the wound” is not appropriate! Typically, a clean dry dressing may be put on and replaced when required until suture removal.
It’s a good idea not to over-do the physical activities soon after the procedure, particularly for complex closures or excisions on the limbs or back. Come to an agreement with your doctor and stick to it!
After the sutures are removed, it is proven that “taping” the wound for up to 3 months reduces scarring. This is particularly important in areas where the scars tend to spread over time eg the back. How do you tape the wound? Just use steristrips or fixomull tape from the pharmacy, cut to size and put over the wound. Fixomull is a breathable fabric that sticks to skin that you can buy from a pharmacy.