Nonmelanoma Skin Cancer
Contents:
General
Skin cancer is present when malignant cells are found in the outer layers of the skin. The skin protects the body against heat, light, infection, and injury. It also stores water, fat, and vitamin D.
The skin has two main layers and several kinds of cells. The top outer skin layer is called the epidermis. It contains three kinds of cells: flat, scaly cells on the surface called squamous cells; round cells called basal cells; and cells called melanocytes, which give the skin its colour.
There are several types of cancer that start in the skin. The most common are basal cell cancer and squamous cell cancer. Melanoma is more uncommon but is a more serious type of cancer. Skin cancer can occur anywhere on the body, but it is most common in places that have been exposed to more sunlight, such as face, neck, hands, and arms.
Types of nonmelanoma skin cancer
Basal Cell (Basal cell carcinomas - BCC)
Basal cell carcinoma is the most common form of skin cancer. These cancers are found in the basal cells, which are at the bottom of the epidermis. It usually occurs on areas of the skin that have been in the sun, most often on the nose. Often this cancer appears as a small raised bump that has a smooth, pearly appearance. Another type looks like a scar and is flat and firm to the touch. Basal cell carcinoma may spread to tissues around the cancer, but it usually does not spread to other parts of the body.
In a few cases, contact with arsenic, exposure to radiation, and complications of burns, scars, vaccinations, or even tattoos are contributing factors.
People who have fair skin, light hair, and blue, green, or grey eyes are at highest risk. Those whose occupations require long hours outdoors or who spend extensive leisure time in the sun are also at risk.
Squamous cell carcinoma
Squamous cell carcinoma is the second most common form of skin cancer. It starts in the epidermis involving the squamous cells that make up most of the upper layers of skin. Squamous cell cancers may occur on all areas of the body, but are most common in areas exposed to the sun such as the ears, lower lip, and the back of the hands.
Squamous cell carcinoma may also appear on areas of the skin that have been burned or exposed to chemicals or radiation. Often this cancer appears as a firm red bump. Sometimes the tumor may feel scaly or bleed or develop a crust.
Although squamous cell carcinomas usually remain confined to the epidermis for some time, they eventually penetrate the underlying tissues if not treated. Squamous cell tumors may spread to nearby lymph nodes and in a small percentage of cases, they spread to distant tissues and organs. When this happens, they can be fatal.
Actinic keratosis
Actinic keratosis is a skin condition that is not cancer, but sometimes changes into squamous cell carcinoma. It usually occurs in areas that have been exposed to the sun, such as the face, the back of the hands, and the lower lip. It appears as rough, red, pink, or brown, raised, scaly patches on the skin, or cracking or peeling of the lower lip that is not helped by lip balm.
Risk factors
Sunlight
Over exposure to sunlight increases the risk of developing nonmelanoma skin cancer and actinic keratosis (which can lead to skin cancer).
Artificial sunlight and sunlamps
Being exposed to artificial sunlight can increase the risk of developing skin cancer.
Skin Colour
Having a fair complexion (blonde or red hair, fair skin, green or blue eyes, history of freckling) increases your risk.
Environment
The level of UV light today is higher than it was 50 years ago because of the reduction of ozone in the earth's atmosphere. Ozone serves as a filter to screen out and reduce the amount of UV light that we are exposed to. With less atmospheric ozone, a higher level of UV light reaches the earth's surface.
Other influencing factors include elevation, latitude, and cloud cover. The rays of the sun are also strongest near the equator. In Antarctica, Chile, and New Zealand, the UV level is much higher than normal especially in the springtime due to the ozone hole in the southern hemisphere.
One factor that actually reduces UV is cloud cover. Climates and micro-climates with regular cloud cover may have a 50% lower level of UV light. The actual amount is affected by the density of the clouds.
Actinic, or solar, keratosis.
Actinic keratoses increases the risk of developing Squamous cell cancer. The keratosis are rough, scaly, slightly raised growths that range in colour from brown to red and may be up to one inch in diameter. They appear most often in older people.
Actinic cheilitis
This is a type of actinic keratosis occurring on the lips that increases the risk of developing Squamous cell carcinoma. Lips become dry, cracked, scaly, and pale or white. It mainly affects the lower lip, which usually receives more sun exposure than the upper lip.
Leukoplakia.
These are white patches on the tongue or inside of the mouth and they have the potential to develop into Squamous cell carcinoma.
Bowen's disease.
This is now thought to be a superficial Squamous cell carcinoma that has not yet spread. It appears as a persistent red-brown, scaly patch which may resemble psoriasis or eczema. If untreated, it may invade deeper structures.
Other contributing risk factors
- Having scars or burns on the skin.
- Being exposed to arsenic.
- Having chronic skin inflammation or skin ulcers.
- Being treated with radiation.
- Taking immunosuppressive drugs (for example, after an organ transplant)
Prevention
Avoid the midday sun
The main way to minimise the risk of skin cancer is to protect the skin from the sun. The following guidelines help to reduce the suns damaging effects.
- Minimize exposure to the sun at midday and between the hours of 10:00AM and 3:00PM.
- Apply sunscreen with at least a SPF-15 or higher, to all areas of the body which are exposed to the sun.
- Reapply sunscreen every two hours, even on cloudy days. Reapply after swimming or perspiring.
- Wear clothing that covers your body and shades your face. (Hats should provide shade for both the face and back of the neck.)
Avoid artificial sunlight
Avoid exposure to UV radiation from sunlamps or tanning salons. UV rays damage skin and can increase the risk of non melanoma skin cancer.
Protect children
Children's skin is very delicate and can burn easily from the sun's rays. The damage done to young skin may not manifest itself until they are older. It is very important to protect children adequately from the sun's harmful rays.
- Children under six months of age should be kept completely out of the sun
- Keep children older than six years of age out of the sun from 10:00am and 3:00pm when sun exposure is at its strongest
- Apply sunscreen liberally and frequently to children
Screening
The following people should ensure they visit their doctor for regular mole checks.
- People with fair skin, whose skin tends to burn quickly
- People who have a large number of abnormal moles
- People with a long history of sun exposure
There is no national screening programme in any European country
Symptoms
Nonmelanoma skin cancer and actinic keratosis often appear as a change in the skin.
Possible signs of nonmelanoma skin cancer include:
- A sore that does not heal
- Areas of the skin that are:
- Small, raised, smooth, shiny, and waxy
- Small, raised, and red or reddish-brown
- Flat, rough, red or brown, and scaly
- Scaly, bleeding, or crusty
- Similar to a scar and firm
Possible signs of actinic keratosis include:
- A rough, red, pink, or brown, raised, scaly patch on the skin.
- Cracking or peeling of the lower lip that is not helped by lip balm.
Diagnosis
The following procedures may be used to diagnose skin cancer:
- Skin examination: A doctor or nurse checks the skin for bumps or spots that look abnormal in colour, size, shape, or texture.
- Biopsy: All or part of the abnormal-looking growth is cut from the skin and viewed under a microscope to see if cancer cells are present.
There are 3 main types of skin biopsies:
- Shave biopsy: A sterile razor blade is used to 'shave-off' the abnormal-looking growth.
- Punch biopsy: A special instrument called a punch or a trephine is used to remove a circle of tissue from the abnormal-looking growth.
- Excisional biopsy: A scalpel is used to remove the entire growth.
Treatment
Treatment depends on the type of cancer, the size and location of the cancer and the patient's overall health.
After the initial diagnosis tests are done to find out if cancer cells have spread within the skin or to other parts of the body, this is called staging.
A biopsy is often the only test needed to determine the stage of nonmelanoma skin cancer. Lymph nodes may be examined in cases of squamous cell carcinoma to see if the cancer has spread to them.
Four types of standard treatment are used to treat non melanoma skin cancer and Actinic Keratosis (Actinic keratosis is not cancer but is treated because it may develop into cancer).
1. Surgery
One or more of the following surgical procedures may be used to treat nonmelanoma skin cancer or actinic keratosis:
Mohs micrographic surgery
The tumor is cut from the skin in thin layers. During surgery each layer of tumor removed are viewed through a microscope to check for cancer cells. Layers continue to be removed until no more cancer cells are seen. This type of surgery removes as little normal tissue as possible and is often used to remove skin cancer on the face.
Simple excision
The tumor is cut from the skin along with some of the normal skin around it.
Shave excision
The abnormal area is shaved off the skin's surface with a small blade.
Electrodesiccation and curettage
The tumor is cut out of the skin with a curette (a sharp, spoon-shaped tool). A needle-shaped electrode is then used to treat the area. The electric current stops the bleeding and destroys cancer cells that remain around the edge of the wound. The process may be repeated one to three times during the surgery to remove all of the cancer.
Cryosurgery or Cryotherapy
This treatment uses an instrument to freeze and destroy tissue.
Laser surgery
A laser beam is used as a knife to make bloodless cuts in tissue or to remove a surface lesion such as a tumor.
Dermabrasion
A rotating wheel or small particles are used to rub away the top layer of skin cells.
2. Radiation therapy or Radiotherapy
Radiation therapy uses high-energy x-rays or other types of radiation to kill cancer cells. The way the radiation therapy is given depends on the type and stage of the cancer being treated.
External radiation therapy uses a machine outside the body to send radiation beams towards the cancer.
Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer.
3. Chemotherapy
Chemotherapy uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping the cells from dividing.
Chemotherapy for nonmelanoma skin cancer and actinic keratosis is usually topical, applied to the skin in a cream or lotion.
Retinoids
Retinoids are derived from vitamin A and are sometimes used to treat or prevent nonmelanoma skin cancer. The retinoids may be taken by mouth or applied to the skin. The use of retinoids is being studied in clinical trials for treatment and prevention of actinic keratosis.
4. Photodynamic therapy (PDT)
Photodynamic therapy uses a drug and a certain type of laser light to kill cancer cells. A drug that is not active until it is exposed to light is injected into a vein or applied on the skin directly. The drug is taken up by all the cells but is retained much longer in cancer cells. Laser light applied to the cancer cells activates the drug and kills the cells. Photodynamic therapy causes little damage to healthy tissue. It is used mainly to treat tumors on or just under the skin or in the lining of internal organs, such as the lungs and the oesophagus.
Biologic therapy /biotherapy or immunotherapy
Biologic therapy is a new treatment in development that uses the patient's immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body's natural defenses against disease.
Basal Cell Carcinoma
Treatment of basal cell carcinoma may include the following:
- Mohs micrographic surgery
- excision
- Electrodesiccation and curettage
- Cryosurgery
- Radiation therapy
- Laser surgery
- Topical chemotherapy with 5-fluorouracil
- Photodynamic therapy
- Clinical trial of systemic retinoids as chemoprevention
- A clinical trial of biologic therapy
Follow-up skin examinations are important for people with basal cell carcinoma because they are likely to have a new or recurrent tumor within 5 years of the first one.
Squamous Cell Carcinoma
Treatment of squamous cell carcinoma may include the following:
- Mohs micrographic surgery.
- Simple excision.
- Electrodesiccation and curettage.
- Cryosurgery.
- Radiation therapy.
- Topical chemotherapy with fluorouracil.
- Laser surgery.
- A clinical trial of biologic therapy.
- A clinical trial of biologic therapy and retinoids.
Follow-up skin examinations are important for people with squamous cell carcinoma because squamous cell carcinoma can spread.
Treatment Options for Actinic Keratosis
Treatment of actinic keratosis may include the following:
- Topical chemotherapy.
- Cryosurgery.
- Electrodesiccation and curettage.
- Dermabrasion.
- Shave excision.
- Laser surgery.
- A clinical trial of topical chemotherapy with retinoic acid
Statistics
World
World wide skin cancers are very common.
Europe
There are approximately 460,000 new cases of skin cancer in Europe each year.
UK
There are more than 46,000 new cases of skin cancer in the UK each year.
Trends
There is a year on year increase in the number of skin cancers diagnosed.
Socio-economic
Skin cancer is an occupational hazard for those who work outdoors in the sunlight.
Survival
If the skin cancer is detected early there is a very high chance of survival. Survival rates are improving thanks to early detection.
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