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Squamous cell carcinoma

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What is squamous cell carcinoma?

Squamous cell carcinoma (SCC) is a type of skin cancer that originates in the squamous cells forming the outer layer of the skin. When squamous cell carcinoma occurs in locations such as the mouth, tongue and throat, it is usually named after the location (i.e. mouth cancer). Squamous cell carcinoma occurs when abnormal squamous cells grow uncontrollably in the skin. Occasionally, these abnormal cells can spread beyond the top layer of the skin to the deeper tissues and, rarely, to distant sites in the body.

The microscopic view of the skin showing the growth of a squamous cell cancer (purple). 

Causes

The cause of skin cancer, as with other cancers, is damage to cellular DNA. This damage results in uncontrolled growth of damaged cells, leading to tumor formation. This damage to skin cells is a result of exposure to ultraviolet (UV) radiation, which can come from sunlight, but also solariums and tanning beds. The intensity of the UV radiation and the time and pattern of exposure to it, all combine to affect the risk of cancer development.

Risk factors

You may be at higher risk of squamous cell carcinoma if any of the following apply to you:

  • Age - the risk of skin cancer increases with age;
  • UV radiation exposure - intense exposure that leads to sunburn, or accumulative exposure, such as working outdoors;
  • Smoking - specific for squamous cell carcinoma of the lips;
  • Tanning - using sun beds and solariums;
  • Family history of squamous cell carcinoma;
  • A weakened immune system, and;
  • Fair skin.

Stages

Treatment outcomes can vary greatly depending on the stage of cancer. Squamous cell carcinoma is staged according to the size and spread of the original tumor in the nearby area and whether the cancer has spread to other parts of the body, such as lymph nodes and organs.

Stage 0

This is also called Bowen's disease, or carcinoma in situ. It refers to the presence of cancerous cells that are contained to their place of origin, in this case the skin.

Stage I

The cancer is 2cm or less in size and has one or none of the following features: it is more than 2mm thick, has grown into the lower layer of the skin, is near a nerve, started on the ear or lip, or looks very abnormal under a microscope.

Stage II

The cancer is greater than 2cm and has two or more of the following features: it has grown into the lower layer of the skin, is near a nerve, started on the ear or lip, or looks very abnormal under a microscope.

Stage III

The cancer has spread to a lymph node on the same side of the body and this lymph node is less than 3cm in size, or the cancer has invaded the bones of the face.

Stage IV

The cancer has spread to a lymph node on the same side of the body and this lymph node is greater than 3cm, or has spread to multiple lymph nodes on either side of the body, or throughout the body to other sites.

Signs and symptoms

Squamous cell carcinoma can appear as a flat reddish patch that grows slowly, or a rough bump on the skin that can be dome-shaped and crusty. Squamous cell carcinoma is generally slow-growing and frequently forms an ulcer that will not heal. Some squamous cell carcinomas begin as pre-cancerous growths called actinic keratosis, which appear as small, pink, itchy, scaly patches.

Visual appearance of a squamous cell carcinoma on the face. 

Methods for diagnosis

Physical examination

Your doctor will examine the abnormal skin section and, if there are any concerns about the cells being potentially cancerous, will perform further tests.

Skin biopsy

A biopsy is a tissue sample taken for microscopic examination in the laboratory. A local anesthetic is often used during biopsies, but this depends on the size of the sample to be removed. Your doctor will choose the best type of biopsy and recommend if an anesthetic is required. There are three main types of skin biopsies:

A punch biopsy procedure to remove a skin sample for skin cancer analysis. 

Types of treatment

Treatment usually involves removal of the cancer at the site where it developed. In the vast majority of cases, this provides the cure.

Simple excision

This is the surgical removal of the abnormal tissue. It is usually performed as a minor procedure, in which a cut is made around the cancer and all the tissue containing cancerous cells is removed.

Cryotherapy

Liquid nitrogen is used to freeze-kill abnormal cells.

Mohs' micrographic surgery

The skin is removed one layer at a time and immediately examined under a microscope for cancer. Layers are removed until no trace of cancer is found.

Electrodessication and curettage

Electrodessication and curettage is a simple surgical technique used to remove smaller squamous cell carcinomas. It involves using an instrument called a curette, which looks like a spoon with a sharp edge, to remove the tissue. This is followed by electrodessication, which uses a needle electrode to apply an electric current to the tissue to stop (cauterize) any bleeding.

Radiation therapy

Radiation therapy uses focused X-rays to destroy cancerous cells and is most commonly used in the treatment of large squamous cell carcinomas, or in situations where the tumor has spread. As the radiation beams hit normal tissue as well as cancerous tissue, radiation therapy is associated with some side effects. For example, radiation directed at the mouth can cause damage to the salivary glands, which then leads to a dry mouth and dental problems.

Chemotherapy

Chemotherapy works by attacking cancer cells and stopping their reproduction. Various medications are used, which can be administered either intravenously or orally. Chemotherapy is generally only used for cancers that are very large, or that have spread from the original site of the tumor.

Side effects occur because chemotherapy can also affect the growth of healthy cells. Your doctor will monitor such side effects and choose the most appropriate dose and type of medication for your situation.

Biological therapy

There is ongoing research into the use of biological therapies for the treatment of squamous cell carcinoma. These drugs target receptors that are involved in regulating the growth of cancer cells. Biological therapies can block this process, inhibiting the growth of the cancer.

Other therapies

Some people diagnosed with cancer seek out complementary and alternative therapies. None of these alternative therapies are proven to cure cancer, but some can help people feel better when used together with conventional medical treatment. It is important to discuss any treatments with your doctor before starting them.

Potential complications

Treatment side effects

In rare cases when the squamous cell carcinoma has spread throughout the body, requiring the use of systemic chemotherapy, side effects potentially include fatigue, nausea and vomiting. Other side effects may be associated with particular agents.

Advanced cancer

Metastasis

This is when the cancer spreads to other parts of the body through the bloodstream and lymphatic system, affecting the vital function of organs. This is very uncommon in the case of squamous cell carcinoma.

Prognosis

Prognosis varies according to the stage of the cancer. Squamous cell carcinoma generally has an excellent prognosis, as metastases are uncommon. Based on this, your doctor will discuss further treatment details suitable for your situation.

Prevention

The best way to prevent skin cancer is by minimizing your exposure to UV radiation, which can be done by avoiding sunlight during the times specific to your state, [1 ] seeking out shade and wearing protective clothing, such as hats and long-sleeved shirts with collars, to protect the arms and neck. Avoiding sun tanning and tanning beds is one of the easiest things you can do to help lower your risk.

If you are at high risk of developing squamous cell carcinoma - for instance, if you are taking medications for long-term suppression of your immune system or have had many squamous cell carcinomas in the past - your doctor may talk to you about other means of prevention. Vitamin A derivatives, called retinoids, have been shown to be effective in prevention of development of new squamous cell carcinomas.

References

  1. UV and sun protection times. Australian Government – Bureau of Meteorology. Accessed 20 March 2015 from link here
  2. Diagnosis and Treatment of Basal Cell and Squamous Cell Carcinoma - American Family Physician. Accessed 18 September 2014 from link here
  3. Non-melanoma skin cancer | Staging non-melanoma skin cancer | Health Library | NHS Inform. Accessed 18 September 2014 from link here
  4. Photodynamic Therapy. Accessed 18 September 2014 from link here
  5. Skin Cancer Symptoms & Signs | CTCA. Accessed 18 September 2014 from link here
  6. Skin Cancer Treatment (PDQ®) - National Cancer Institute. Accessed 18 September 2014 from link here
  7. Squamous cell carcinoma: Signs and symptoms. Accessed 18 September 2014 from link here
  8. Tests for skin cancer?: Cancer Research UK?: CancerHelp UK. Accessed 18 September 2014 from link here
  9. Treatment of melanoma and nonmelanoma skin ... [Adv Exp Med Biol. 2008] - PubMed - NCBI. Accessed 18 September 2014 from link here
  10. Types of skin cancer?: Cancer Research UK?: CancerHelp UK. Accessed 18 September 2014 from link here

10 Most frequently asked questions (FAQs)

What is squamous cell carcinoma?
Squamous cell carcinomas is a type of skin cancer that originates in the squamous cells, which form the outer layer of the top layer of skin (epidermis).
What are the signs and symptoms of squamous cell carcinoma?
Sometimes squamous cell carcinoma begins as a pre-cancerous growth called an actinic keratosis, which is visible as small, pink, itchy, scaly patches. Squamous cell carcinoma appears as a flat reddish patch that grows slowly, or a bump on the skin that is rough and sometimes dome-shaped and crusty. SCC often appears as an ulcer that won't heal.
What causes squamous cell carcinoma?
Squamous cell carcinoma is caused by damage to the DNA of squamous cells that causes them to replicate uncontrollably. For squamous cell carcinoma of the skin, the cellular damage is caused by UV radiation, which can come from sunlight, but also solarium tanning beds. Lifetime exposure, the pattern of exposure, as well as the intensity of UV radiation are all contributing factors to the development of skin cancer.
Who gets squamous cell carcinoma?
People at greatest risk of developing squamous cell carcinoma include those who have been sunburnt, who have accumulated long-term exposure to the sun (for instance by working outdoors), people who sunbathe or use tanning beds, people with a family history of the condition, fair-skinned people and those with weakened immune systems.
How is squamous cell carcinoma diagnosed?
A pathologist will diagnose squamous cell carcinoma by examining a sample of the affected skin.
How is squamous cell carcinoma treated?
Squamous cell carcinoma is treated using a combination of surgery, cryosurgery, radiation therapy, biologic and retinoid therapy and chemotherapy.
Can squamous cell carcinoma be cured?
The prognosis for squamous cell carcinoma varies according to the stage of the cancer. If the disease is detected before it has had time to spread throughout the body, the prognosis is usually good.
Can squamous cell carcinoma be prevented?
You cannot prevent skin cancer, but you can reduce your risk by limiting exposure to UV radiation during peak UV times, not tanning in the sun or using sun beds, seeking out shade and wearing protective clothing such as hats and long-sleeved shirts with collars to protect the arms and neck.
What are the chances of squamous cell carcinoma returning?
Squamous cell carcinoma can return after treatment. If it does, recurrence usually occurs in the first two years after surgery.
How common is squamous cell carcinoma?
Skin cancer, including squamous cell carcinoma, is the most common type of cancer.

Related topics

Melanoma

Melanoma is a type of cancer that starts in the melanocyte cells of the skin, usually due to damage from UV light (sunlight). A new or changing mole may be a sign of a potential melanoma. Melanoma cells can spread to other parts of the body.

Skin cancer

Skin cancer is a group of cancers that originate from several different types of skin cells. Treatment options vary, depending on the type and stage. Protective measures, such as minimising sun exposure and wearing appropriate clothing outdoors, can go a long way towards preventing skin cancer.

Basal cell carcinoma

Basal cell carcinoma (BCC) is cancer that starts in the skin’s basal cells, usually due to damage from UV light (sunlight). BCC often looks like a raised, pearly lump or sore, but can form deep ulcers as it enlarges. It rarely spreads in the body.

Bladder cancer

Bladder cancer is the name for cancers that arise in the tissues of the bladder, the organ that stores urine before it is expelled from the body during urination. Abnormal cells can form a tumour, affect urination and spread throughout the body.

About this article

Title: Squamous cell carcinoma

Author: Jonathan Meddings BMedLabSc (Hons)

First Published: 22 Sep 2014

Last reviewed: 17 Jan 2022

Category: Information on Squamous cell carcinoma

Average rating: 4.2 out of 5 (1556 votes)

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