What is the treatment of SCC?
Invasive SCC will need to be surgically removed with a margin of clinically normal-looking skin around the lesion. The margin required will tend to be greater than for a BCC. The exact margin chosen is a judgment that takes into consideration the risk factors for aggressive SCC
It’s helpful to consider the risk factors for SCC recurrence in terms of risk factors before biopsy and risk factors from the pathology report.
The risk factors for a more aggressive SCC that are known prior to surgical excision are:
- SCC found in these sites are more likely to re-occur: Ear or hair-bearing lip.
- Being on immunosuppressive medication
- Having previous treatment for that SCC
- Larger SCC is more likely to re-occur after treatment (eg. more than 2cm in diameter)
- Not being very rapidly growing (as SCCs do tend to grow rapidly, this is not that helpful a risk factor)
The standard excision margin is around 3-4mm, but that precise figure will depend on clinical features and patient preference.
Following excision with margins, will any further treatment (eg. surgery) be required? The risk factors in the pathology report for an aggressive SCC are:
- Invading nerves in the skin (“Perineural invasion”) – up to 5% of SCC shows perineural invastion.
- “Poorly differentiated” (see pathology report below) SCC.
- SCC Invading deep into the skin (dermis).
- unusual pathological variants (eg “spindle cells”).
The latest guidelines highlight the importance of the depth of an SCC. Depth is measured using the “Breslow thickness,” which is the distance from the top of the skin (almost) to the deepest level of The SCC. The Breslow thickness is also used to stage melanoma, and its use to help stage SCC is a recent development. A Breslow thickness of at least 2mm indicates an SCC that may be more aggressive.
Further treatment (Surgery) will often be required when the above pathological features are identified.
The excision margin required for SCC will tend to be greater than for a BCC