Definition
Skin cancer is a malignant growth on the skin which can have many causes. Skin cancer generally develops in the epidermis (the outermost layer of skin), so a tumor is usually clearly visible. It is the most common form of human cancer. It develops primarily on areas of sun-exposed skin, including the scalp, face, lips, ears, neck, chest, arms and hands, and on the legs in women. It has been estimated that nearly half of all Americans who live to age 65 will develop skin cancer at least once.
The most common warning sign of skin cancer is a change in the appearance of the skin, such as a new growth or a sore that will not heal.
The top layer of skin (the epidermis) is as thin as a pencil line, and it provides a protective layer of skin cells that your body continually sheds. The epidermis contains three types of cells:
a) Squamous cells that lie just below the outer surface,
b) Basal cells which produce new skin cells and sit beneath the squamous cells,
c) Melanocytes, which produce the pigment that gives skin its normal color (melanin) and are located in the lower part of the epidermis. When the controlled development of these cells is disturbed by various reasons, a skin cancer may occur.
Risk Factors
People with certain risk factors are more likely to develop skin cancer. These risk factors can be listed as below:
Lighter natural skin color
Family history of skin cancer
Personal history of skin cancer
Exposure to the sun through work and play
A history of sunburns early in life
Skin that burns, freckles, reddens easily, or becomes painful in the sun
Blue or green eyes
Blond or red hair
Certain types and a large number of moles
UV and Sun Protection
The best known cause of skin cancer development is the ultraviolet (UV) radiation found in sunlight, commercial tanning lamps and tanning beds. Both ultraviolet A and ultraviolet B contribute to skin cancer. The best way to prevent skin cancer is the protection from the sun. Center for Disease Control (CDC) recommends five easy options for sun protection:
Seek shade, especially during midday hours (10:00 a.m.-4:00 p.m.), when UV rays are strongest and do the most damage.
Cover up with clothing to protect exposed skin.
Get a hat with a wide brim to shade the face, head, ears, and neck.
Grab shades that wrap around and block as close to 100% of both UVA and UVB rays as possible.
Rub on sunscreen with sun protective factor (SPF) 15 or higher, and both UVA and UVB protection.
Alert
The most common warning sign of skin cancer is a change on the skin, especially a new growth or a sore that doesn’t heal. The cancer may start as a small, smooth, shiny, pale, or waxy lump. Or it can appear as a firm red lump. Sometimes, the lump bleeds or develops a crust. Skin cancer can also start as a flat, red spot that is rough, dry, or scaly. Actinic keratosis, which appears as rough, red or brown scaly patches on the skin can sometimes turn into a squamous cell cancer. Like skin cancer, it usually appears on sun-exposed areas but can be found elsewhere.
3 Different Forms of Skin Cancer
Changes in the skin are not sure signs of cancer; however, it is important to see a doctor if any symptom lasts longer than 2 weeks. There are mainly three different forms of skin cancer.
Basal cell carcinoma: This form makes up approximately 70-75 % of all. It is usually locally destructive and progress very slowly.
Squamous cell carcinoma: While making about 25 % of all skin cancers, it can be more aggressive and rarely spread to local lymph nodes.
Malignant melanoma: 1-5 %. It is a very aggressive tumor and very frequently seen with regional and/or distant metastasis.
Biopsy
When an area of skin does not look normal, the doctor may remove all or part of the growth, which is called a biopsy. This tissue goes to histopathologic examination to check for cancer cells. A biopsy is the only sure way to tell if the problem is cancer.
Metastasis
The skin cancer is usually a local disease and very rarely spreads beyond the skin, except for malignant melanoma. Only in very large and long lasting cancer may need regional and distant metastasis to decide on the stage of the disease.
Treatment
In treating skin cancer, the main goal is to remove or destroy the cancer completely with as small a scar as possible. Best treatment option for everybody can change according to the location and size of the cancer, the risk of scarring, and the person’s age, general health, and medical history. There are many treatment options for skin cancer.
Curettage and Electrodesiccation: Under local anesthesia the cancer is scooped out with a sharp and spoon-shaped instrument known as curette. The area is also treated by an electric current from a special machine (cautery) to control bleeding and destroy any cancer cells remaining around the edge of the wound (electrodesiccation). Most patients develop a flat, white scar.
Mohs’ Surgery: Mohs’ technique is a special type of surgery used for skin cancer. Its purpose is to remove all of the cancerous tissue and as little of the healthy tissue as possible. It is especially helpful when the shape and depth of the tumor is not clear. This method should be used only by doctors who are specially trained in this type of surgery and can be necessary in less than 10 % of the cases.
Cryosurgery: Extreme cold may be used to treat actinic keratosis and certain small skin cancers. Liquid nitrogen is applied to the growth to freeze and kill the abnormal cells. After the area thaws, the dead tissue falls off. More than one freezing may be needed to remove the growth completely. Cryosurgery usually does not hurt, but patients may have pain and swelling after the area thaws. A white scar may form in the treated area.
Laser Therapy uses a narrow beam of light to remove or destroy cancer cells. This approach is sometimes used for cancers that involve only the outer layer of skin. Photodynamic therapy destroys cancer cells with a combination of laser light and drugs that make the cells sensitive to light.
Surgery is the mainstay of skin cancer treatment for today. Depending on the size and location of the tumor, the tumor is usually removed with safety margins of 4-7 mm. Then the defect can be closed primarily, can be covered by adjacent skin (flaps) or a piece of healthy skin taken from another part of the body or can be left open to heal by itself (secondarily).
Radiation therapy is usually used for cancers that occur in areas that are hard to treat with surgery. Several treatments may be needed to destroy all of the cancer cells. Radiation therapy may cause a rash or make the skin in the area dry or red.
Topical Chemotherapy is the use of anticancer drugs in a cream or lotion applied to the skin. Actinic keratosis and very limited superficial cancers can be treated effectively this method. Intense inflammation is common during treatment, but scars usually do not occur.
Follow Up
For all cancers, a serious followup is necessary. Besides, it is known that if someone had a skin cancer before, there is a 50 % chance of having another one within the next 3 years. So the doctor who cures the cancer always asks the patient to come for a routine followup visit on a regular basis for at least 3-5 years.