Реферат на тему Skin Cancer Essay Research Paper Skin cancer
Skin Cancer Essay, Research Paper
Skin cancer is a disease in which cancer (malignant) cells are found in the outer layers of the skin. Skin protects your 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 layer of skin 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 gives skin its color. The inner layer of skin is called the dermis. This layer is thicker, and contains blood vessels, nerves, and sweat glands. The hair on skin also grows from tiny pockets in the dermis, called follicles.
There are several types of cancer that start in the skin. The most common are basal cell cancer and squamous cell cancer. These types of skin cancer are called nonmelanoma skin cancer. Melanoma is a type of skin cancer that starts in the melanocytes. It is not as common as basal cell or squamous cell skin cancer, but it is much more serious. Skin cancer is more common in people with light colored skin who have spent a lot of time in the sunlight. Skin cancer can occur anywhere on the body, but it is most common in places that have been exposed to more sunlight, such as your face, neck, hands, and arms. Skin cancer can look many different ways. The most common sign of skin cancer is a change on the skin, such as a growth or a sore that wont heal. Sometimes there may be a small lump. This lump can be smooth, shiny and waxy looking, or it can be red or reddish brown. Skin cancer may also appear as a flat red spot that is rough or scaly. Like most cancers, skin cancer is best treated when it is found early. If a spot or lump on your skin is detected, a doctor may remove the growth and look at the tissue under a microscope. This is called a biopsy. Most nonmelanoma skin cancers can be cured. The chance of recovery (prognosis) and choice of treatment depend on the type of skin cancer and how far it has spread. Other kinds of cancer that may affect the skin include cutaneous T-cell lymphoma, a cancer of the lymph system, and Kaposis sarcoma. Cancers that start in other parts of the body may also spread (metastasize) to the skin. Once skin cancer is found, many tests may be done to see if the cancer has spread.
Here is a brief rundown of the different types of skin cancer: Basal cell cancer- Basal cell cancer is the most common type of nonmelanoma skin cancer. It usually occurs on areas of your skin that have been in the sun. Often this cancer appears as a small raised bump that has a smooth, pearly appearance. Another type looks like a scar, and it is firm to the touch. Basal cell cancers may spread to tissues around the cancer, but it usually does not spread to other parts of the body. Squamous cell carcinoma- Squamous cell tumors also occur on areas of your skin that have been in the sun, often on the top of the nose, forehead, lower lip, and hands. They may also appear on areas of skin that have been burned, exposed to chemicals, or had x-ray therapy. Often this cancer appears as a firm red bump. Sometimes the tumor may feel scaly or bleed or develop a crust. Squamous cell tumors may spread to the lymph nodes in the area (lymph nodes are small bean-shaped structures that are found throughout the body; they produce and store infection-fighting cells). Actinic keratosis-Actinic keratosis is a skin condition that is not cancer, but can change into basal cell or squamous cell skin cancer in some people. It appears as rough, red or brown, scaly patches on the skin, usually in areas that have been exposed to the sun.
There are treatments for all patients with skin cancer. Three kinds of treatments are used: surgery (taking out the cancer) chemotherapy (using drugs to kill cancer cells) radiation therapy (using x-rays to kill cancer cells). Biological therapy (using your bodys immune system to fight cancer) is being tested in clinical trials. Many skin cancers are treated by doctors who treat skin diseases (dermatologists). Often, the cancer can be treated in the doctors office. Surgery is the most common treatment for skin cancer. The doctor may remove the cancer using one of the following: Electrodesiccation and curettage burns the lesion and removes it with a sharp instrument. Cryosurgery freezes the tumor and kills it. Simple excision cuts the cancer from your skin along with some of the healthy tissue around it. Micrographic surgery removes the cancer and as little normal tissue as possible. During this surgery, the doctor removes the cancer and then uses a microscope to look at the cancerous area to make sure no cancer cells remain. Laser therapy uses a narrow beam of light to remove cancer cells. Depending on the size of the cancer, skin may be taken from another part of the patient s body and put on the area where the cancer was removed. This is called a skin graft. Radiation therapy uses x-rays to kill cancer cells and shrink tumors. Radiation therapy for skin cancer comes from a machine outside the body (external radiation therapy). Chemotherapy uses drugs to kill cancer cells. In treating skin cancer, chemotherapy is often given as a cream or lotion placed on the skin to kill cancer cells (topical chemotherapy). Chemotherapy may also be taken by pill, or it may be put into the body by a needle in a vein or muscle. Chemotherapy given in this way is called a systemic treatment because the drug enters the bloodstream, travels through the body, and can kill cancer cells outside the skin. Systemic chemotherapy is being tested in clinical trials. Biological therapy tries to get your own body to fight cancer. It uses materials made by the body or made in a laboratory to boost, direct, or restore the bodys natural defenses against disease. Biological therapy is sometimes called biological response modifier (BRM) therapy or immunotherapy. Photodynamic therapy uses a certain type of light and a special chemical to kill cancer cells.