Squamous cell carcinoma, or SCC, is a cancer of the cells at the bottom of the skin's outermost layer.
- The skin is the largest organ in body.
Its purposes are to:
- Act as a barrier to protect the body from injury and keeps out infection.
- Keeps in necessary fluids and proteins.
- Protects the body from the harmful effects of ultraviolet light.
- Helps to control our body temperature.
Squamous cell carcinoma is not infectious and cannot be passed on to other people.
There are two layers in the skin:
- the epidermis
- underneath that, the dermis
The epidermis contains three types of cells:
- On the surface are flat cells, known as squamous cells
- Under the layer of squamous cells are rounder cells called basal cells
- In between the basal cells are melanocytes
Most squamous cell carcinomas are slow growing. If it is left untreated for a long time, squamous cell carcinoma can spread to other parts of the body.
However, most people treated for squamous cell carcinoma are completely cured with simple treatment.
What causes squamous cell carcinoma?
There are risk factors that increase the probability of getting squamous cell carcinoma.
- Exposure to Ultra Violet (UV) rays from the sun or a sun bed.
- Previous radiotherapy.
- Overexposure to chemicals, coal, tar, soot, pitch, asphalt, creosotes, paraffin waxes, petroleum derivatives, hair dyes, cutting oils, arsenic.
- Family history of SCC.
- Reduced immunity: e.g. if a person has HIV or is taking immune suppressant drugs post organ transplant.
Squamous cell carcinomas most often develop in areas that have been damaged by exposure to the sun.
They are mainly found on the face, bald scalps, arms, backs of hands and lower legs. SCC have a scaly appearance and sometimes have a hard, horny cap and sometimes can feel tender to touch.
What are the symptoms?
Squamous cell carcinomas can appear in a variety of forms. They are usually painless and grow slowly.
They can appear anywhere on the body but are most likely to occur on exposed skin, especially the face.
Squamous cell carcinomas can develop as a small lump on the skin. They may:
- be smooth and pearly
- look waxy
- be a firm, red lump
- bleed sometimes
- develop a crust
- begin to show signs of healing and yet never quite heal
- may be itchylook like a flat, red spot, which is scaly and crusty
TIP: If you have any of these symptoms you should have them checked by your doctor - but remember, they are common to many illnesses other than SCC.
How is it diagnosed?
After visiting a GP a referral will probably be made to a hospital for some tests. These may include:
If the results of the tests show a squamous cell carcinoma, another referral will be made to a doctor who specialises in the treatment of the skin (called an dermatologist).
The stage of a cancer is a term used to describe its size and whether it has spread beyond its original site.
A commonly used staging system for squamous cell carcinoma is:
- Stage 0: Also called carcinoma in situ. Carcinoma in situ means that cancer cells are present, but they are all contained in a small area in the top layer of skin (the epidermis). They have not started to spread or grow into deeper layers of skin. Squamous cell stage 0 is also called Bowen's disease. If it is not treated, it can develop into a squamous cell skin cancer.
- Stage 1: Cancer is less than 2cm across and has not spread.
- Stage 2: Cancer is more than 2cm across and has not spread.
- Stage 3: Cancer has spread into the tissues under the skin and possibly to nearby lymph nodes.
- Stage 4: Cancer has spread to another part of the body. This very rarely occurs with squamous cell cancers of the skin.
How is it treated?
A team of doctors and other staff at the hospital will plan treatment. It will depend on the size of the tumour and where it is.
Treatment may be coordinated by an oncologist (a doctor who specialises in treating cancer with chemotherapy), a dermatologist (a doctor who specialises in the skin) and a radiologist (a doctor who specialises in treating cancer with radiation).
Treatment may involve:
- Photodynamic therapy
Surgery for Squamous Cell Carcinoma
- The aim of surgery is to remove the tumour. When larger tumours are removed, skin grafts are sometimes needed to replace the removed skin. A skin graft is a thin layer of healthy skin taken from another part of the body.
- This is done under either a local or general anaesthetic. In many cases, surgery is the only treatment needed.
Imiquimod cream for Squamous Cell Carcinoma
- Imiquimod is a cream that destroys the skin cancer by stimulating the body’s immune system to fight the cancer.
- This treatment is not invasive, although it has to be used for approximately 7 weeks, and can cause the skin to become red and sore.
Cryotherapy for Squamous Cell Carcinoma
- If the cancer is very small and only affecting the surface layers of the skin it may be possible to remove it by freezing it.
- This is called cryotherapy or cryosurgery. Liquid nitrogen is sprayed on to the cancer to freeze it. The cold can be a bit painful when the liquid nitrogen is applied (some patients describe the feeling as like a bee-sting).
Photodynamic therapy for Squamous Cell Carcinoma
- Photodynamic therapy (PDT) is a newer treatment for skin cancer. PDT uses laser, or other light sources, combined with a light-sensitive drug (sometimes called a photosensitising agent) to destroy cancer cells.
- A photosensitising cream will be applied to the skin. The patient then needs to wait for approximately four to six hours before being treated.
- Treatment with the light will last 20-45 minutes.
Radiotherapy for Squamous Cell Carcinoma
Radiotherapy is often given to people with squamous cell carcinoma before and/or after surgery. This is to shrink and destroy the tumour.