Squamous Cell Carcinoma (BCC, rodent ulcer)
What is a Squamous Cell Carcinoma?
This is the second most common type of skin cancer and is most commonly found in older people, but the popularity of sunny holidays and recreational use of sunbeds means that we are seeing them in younger age groups. SCC is a cancer of the keratinocytes of the skin.The incidence is continuing to increase. At Kings College in the United Kingdom, a 10-fold increased incidence rate was seen in SCCs from 1970 to 1992. [ref.1]
The most likely sites are the areas of skin often exposed to the sun, typically the face, ears, lips, mouth and hands. The appearance varies but is usually a scaly lump, nodule, ulcer or non-healing sore. They often start as small hard white or skin-coloured lumps in the skin that grow at a variable rate. Squamous cell carcinomas have the ability to spread to other parts of the body, but do not often do so. If left untreated, the tumour will increase in size and damage the surrounding skin. It may then spread to local lymph nodes or around the body and ultimately kill an individual.
Reference
Hughes JR, Higgins EM, Smith J, Du Vivier AW. Increase in non-melanoma skin cancer: the King’s College Hospital experience (1970-92). Clin Exp Dermatol 1995;20:304-7].
Examples of Squamous Cell Carcinoma:
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What causes a squamous cell carcinoma?
The main cause is exposure to sunlight over many years. Occasionally, a squamous cell carcinoma may be caused by exposure to certain substances used in industry, such as tar. They can sometimes develop in chronic ulcers or in patients who are on drugs that suppress the immune system.
Risk factors for SCC
UVR – excessive sun exposure
PUVA - photochemotherapy
OTR immunosuppression
Organ Transplantation recipient - OTR are more at risk of developing skin cancer compared to other patients
Chronic ulcer
Precancerous lesions such as Actinic keratoses or Bowens disease
Treatment of Squamous cell carcinoma
1 WLE = wide local excision
2 Mohs micrographic surgery
3 Radiotherapy
In the majority of cases, the SCC can be removed under local anaesthetic on one visit.
Surgical Excision
For well defined tumours, <2cm in diameter, excision with at least 4mm margin completely removes the tumour if 95% of cases. Larger tumours, thicker tumours, those on high risk sites or those with poor differentiation should be excised with wider margins
Radiotherapy may be appropriate for
- selected individuals
- certain lesions
- as an alternative to surgery
Certain factors predict the ability of an SCC to metastasise
- Size >2cm
- Site - ear, lip
- Host immunosuppression
- Perineural invasion
- Differentiation - poorly > moderately > well Depth -thicker >thinner
- Aetiology- non-sun exposed sites, areas of chronic inflammation mucosal SCC > cutaneous SCC
For metastatic disease - 25%.
In 2004, there were 540 deaths from non melanoma skin cancer http://info.cancerresearchuk.org/cancerandresearch/cancers/melanoma/
[accessed 30 May 2007]









