Surgery

Surgical excision is the primary treatment for nearly all basal cell carcinomas. Radiotherapy has a role in a limited number of lesions for which surgery would be too risky, too extensive, or insufficient.

Local Excision

Technique

Anaesthesia is usually local, but some patients may require general anaesthesia especially for larger lesions or if a skin flap is required.
The surgeon makes an incision through the epidermis and dermis to the subcutaneous tissues with a margin of 5 - 10 mm depending on the size and morphology of the lesion. The lesion and surrounding skin are lifted and the deep margin excised. Closure is usually primary with apposition of opposing skin edges.
The procedure usually takes less than 15 minutes unless the lesion is large or diffusely invading.

Advantages

Surgical excision is usually rapid and nearly always curative (99% +). Most patients do not require anaesthetic or a hospital stay. The tumour can be examined following resection to confirm diagnosis and margins.

Disadvantages

There is significant tissue loss with standard surgical excision. This can be particularly problematic in areas where there is little excess skin (eg. the anteromedial lower leg), where cosmesis is imporant (eg. ear, eyelid) or when the skin has other functions (such as the lip). Margins may be positive when an infiltrating or morpheic subtype is present. Some of these issues can be overcome by using a partial or full thickness skin graft.


Mohs Micrographic Surgical Excision

Mohs micrographic surgery was developed by Dr. Frederic Mohs in the 1930s and the first article regarding it was published in 1941 when he was 31 years old. It was used as a means of completely removing a malignancy while preserving as much uninvolved tissue as possible. The initial procedure used a painful zinc chloride fixative and took several days to complete; results were very good with cure rates of 90%. Dr Mohs died in 2002 from progressive myasthenia gravis.
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It was refined over the following thirty years and in 1974 Theodore Tromovitch and Samuel Stegman published a fresh-tissue technique that did away with the need for zinc chloride, utilising local anaesthetic and frozen sections instead. The technique has continued to improve since then and is now used mostly for difficult tumours of the head and neck region.

It is most commonly performed by specialist dermatological surgeons who require training in both surgery and pathological techniques.

It is an time consuming and expensive procedure, involving:

  • Initial excision
  • Examination of surgical margins while the patient remains in theatre
  • Mapping of positive margins
  • Re-excision of positive margins
  • Re-examination of new margins

This process is repeated until margins are clear. Tissue reconstruction is then performed.
Mohs surgery is typically performed for surgical sites where retention of normal tissue is important (eg. lip, ear, eyelid) or when the malignancy is of an aggressive or infiltrative type. It is of particular use in morphaeic/infiltrative forms of basal cell carcinoma for which margins are indistinct macroscopically.

Mohs surgery was introduced into Australia in 1978 and can be obtained in most state capitals.

In some areas Mohs surgery will be inferior to radiotherapy due to the extent of resection and difficulty in reconstruction, particularly in older patients who may be unable to tolerate such an extended operation. In other areas, it is unnecessary due to the ease of identification of the tumour and/or sufficient surrounding normal tissue for reconstruction to allow generous margins.

Advantages

Mohs surgery has the best rates of cure and also retains the most normal tissue, while at the same time allowing for complete examination of surgical margins.

Disadvantages

Mohs surgery is expensive and time consuming given the number of histological examinations required while the patient is still in theatre. Extensive tumours still require extensive excision which may still result in a poor cosmetic or functional outcome.


Diathermy and Curettage

Curettage of small basal cell carcinomas is often curative and has better cosmesis than other surgical techniques. It can be coupled with diathermy (aka electrodesiccation) to help control bleeding.

Advantages

Fast procedure which is curative for most small BCCs. In skilled hands the tumour mass can be removed with minimal loss of normal tissue.

Disadvantages

Margins can not be examined. The technique is not suitable for lesions of 6 mm or greater in size unless they are specially selected. It is also not suitable for infiltrative or superficial BCCs.


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