Skin lesions, such as basal and squamous cell cancers, require treatment and the decision is often made to remove them surgically. There are a number of techniques available to achieve this, depending on the position and size of the lesion in question.
A local anaesthetic injection will be applied to the area of abnormal cells and the dermatologist will cut around and under the lesion, leaving – in the case of a small basal cell carcinoma (BCC) – a 4 mm margin of normal skin around it.
For BCCs larger than 2 cm in diameter, a 5 mm margin may be considered appropriate, as is normal when removing squamous cell cancers. The procedure is usually completed in 30-60 minutes and the defect is repaired with sutures, which normally remain in place for a week or so. The specimen is then sent for analysis and confirmation of complete excision.
In the case of a suspected malignant melanoma, an excisional biopsy of the suspicious area with a margin of 2 mm of normal skin around it is normally obtained and sent for analysis to establish a firm diagnosis before further surgery is undertaken.
This procedure involves the removal of cancerous cells by scraping them away with a surgical instrument called a curette. Following removal, an electric needle is used to destroy any remaining cancerous tissue. This technique is useful for the removal of superficial BCCs.
If a cancer recurs following incomplete excision, the treatment of choice may be Mohs’ micrographic surgery. This technique involves removing abnormal cells in a step by step process, layer by layer and sending frozen sections of the tissue for analysis while the patient is still in the department. If it has not been completely excised, further layers are removed until only healthy cells remain.
This process spares tissue as it only requires narrow margins and that is a bonus when surgery is again being performed on a previously operated site. It also has a very high success rate, approaching 99%. Mohs is also the preferred option when dealing with facial cancers, very large cancers or those invading nerves.
Following removal of a large BCC or squamous cell cancer, the resultant defect may be too large to be repaired by stitching the edges of the wound together. In such cases, a skin graft harvested from another part of the body may be required to aid healing and restore the appearance of the wound site.