What is Skin Cancer (Squamous Cell Carcinoma of the Skin)

Squamous Cell Carcinoma of the Skin is one type of skin cancer.

The skin is the largest organ of the body. It serves as a protective barrier between us and the environment, keeping water in and infection out. The skin in composed of two main layers:

  • The epidermis – consisting of keratinised stratified squamous epithelium; and
  • The dermis – a dense connective tissue.

Epidermal components of the skin include hair follicles and hair; sweat, sebaceous and mammary glands; and nails.

The functions of the skin include:

  • Providing a protective barrier from the external environment;
  • Homeostasis – assisting in the regulation of body temperature and water loss;
  • Sensory function – providing information about the external environment;
  • Excretion of body fluids – sweating; and
  • Synthesis of vitamin D on exposure to sunlight.

In addition, cells in the deep part of the epidermis make melanin to protect us from ultraviolet radiation. From a cancer viewpoint, the most important cells in the epidermis are squamous cells, basal cells and melanocytes.

Statistics on Skin Cancer (Squamous Cell Carcinoma of the Skin)

It is the second most common form of skin cancer. It occurs with increasing age with sex incidence being more common in males.

Geographically, the tumour is found worldwide, but with striking geographical variation, with incidence decreasing with increasing distance from the equator. Squamous cell carcinomas are more common in areas with high levels of sunlight.

Risk Factors for Skin Cancer (Squamous Cell Carcinoma of the Skin)

The most important predisposing factor in the development of squamous cell carcinoma is the exposure to ultraviolent radiation (UVB) sunlight. Chronic exposure to sunlight is associated with premature aging, blunting of the immunological responses of the skin to environemnstal antigens and the development of premalignant and malignant neoplasms. However, there are also important genetic contributions to the development of squamous cell carcinoma. Risk factors relating to exposure and susceptability to sunlight include: fair skin, Northern European ancestory, childhood freckling and the number of past sunburns. Squamous cell carcinoma is the skin cancer most closely associated with cumulative sun exposure.

Other predisposing factors include: Ionising radiation, chemical carcinogens such as cigarette smoke and betel nut chewing (particularly in the mouth and on the lips), chronic immunosuppression (incidence of squamous cell carcinoma much greater than that of BCC), rare genetic conditions such as xeroderma pigmentosa, and the Human Papilloma Virus (HPV) that has been found in association with some cutaneous SCC. Squamous cell carcinoma, in particular, is found in patients following organ transplantation. SCC can also arise in areas of scarring (known as Marjolin’s ulcer) due to burns, chronic ulcers or sinus tracts.

Progression of Skin Cancer (Squamous Cell Carcinoma of the Skin)

This type of tumour spreads by lymphatic infiltration with spread to regional lymph nodes. Systemic spread occurs later in the course of the disease.

How is Skin Cancer (Squamous Cell Carcinoma of the Skin) Diagnosed?

General investigations may show no abnormality with the vast majority of squamous cell carcinomas.

Prognosis of Skin Cancer (Squamous Cell Carcinoma of the Skin)

Squamous cell carcinoma of the skin is associated with a good prognosis, with less than 5% of lesions showing evidence of regional lymph node metastases at diagnosis. With appropriate treatment the 5 year disease free survival rate is at least 95%. As with most malignancies, the earlier the stage at diagnosis, the better the prognosis.

How is Skin Cancer (Squamous Cell Carcinoma of the Skin) Treated?

The treatment of choice for squamous cell carcinoma is surgical excision to a margin of at least 0.5cm both in depth and laterally. Simple excision gives cure rates of approximately 90% whilst Moh’s surgery is associated with cure rates of around 97%. Adjuvant radiotherapy can be used when the margins are compromised by adjacent vital structures. Radiotherapy is also associated with good cure rates but is reserved for patients not able to tolerate surgical excision. Interferon and photodynamic therapy are newer experimental treatment modalities being explored.

Improvement in symptoms is an important measurement. Specific monitoring may be by clinical follow-up to detect recurrence or the appearance of new primary lesions. This should include visual inspection and palpation for any deeper recurrence or lymphatic spread, as well as questioning the patients about any altered sensation in the area of the lesion.

The symptoms that may require attention are somatic pain from bony infiltration and neurogenic pain if nerve tissue is compressed. Visceral pain from metastatic disease may also occur.

Skin Cancer (Squamous Cell Carcinoma of the Skin) References

Visit Virtual Medical Centre’s guide to Ultraviolet Radiation.

All content and media on the HealthEngine Blog is created and published online for informational purposes only. It is not intended to be a substitute for professional medical advice and should not be relied on as health or personal advice. Always seek the guidance of your doctor or other qualified health professional with any questions you may have regarding your health or a medical condition. Never disregard the advice of a medical professional, or delay in seeking it because of something you have read on this Website. If you think you may have a medical emergency, call your doctor, go to the nearest hospital emergency department, or call the emergency services immediately.