- Cancer of the skin is the most common of all cancer types
- Squamous cell carcinoma is the second most common form of skin cancer. An estimated 700,000 cases of squamous cell carcinoma are diagnosed each year in the US
- Approximately 65 percent of all squamous cell carcinomas arise in lesions that previously were diagnosed as actinic keratoses
- Actinic keratosis is the most common pre-cancer; it affects more than 58 million Americans
The skin is the body’s largest organ. It protects against heat, light, injury, and infection. It helps control body temperature. It stores water and fat. The skin also makes vitamin D.
The skin has two main layers
- Epidermis: The epidermis (the top layer of the skin) is mostly made of flat cells called squamous cells. Under the squamous cells in the deepest part of the epidermis are round cells called basal cells. Cells called melanocytes make the pigment (color) found in skin and are located in the lower part of the epidermis.
- Dermis: The dermis (under the epidermis) contains blood vessels, lymph vessels, and glands. Some of these glands make sweat, which helps cool the body. Other glands make sebum, an oily substance that keeps the skin from drying out. Sweat and sebum reach the surface of the skin through tiny openings called pores.
What is squamous cell carcinoma?
Squamous cell carcinoma (SCS) is an uncontrolled growth of abnormal cells arising in the squamous cells, which compose most of the skin’s upper layers (the epidermis). Squamous cell carcinomas may occur on all areas of the body including the mucous membranes and genitals, but are most common in areas frequently exposed to the sun, such as the rim of the ear, lower lip, face, bald scalp, neck, hands, arms and legs. About 2 out of every 10 skin cancers are squamous cell carcinomas.
Research has shown that people with certain risk factors are more likely than others to develop squamous cell carcinoma. A risk factor is anything that increases a person’s chance of developing a disease. Studies have found the following risk factors for squamous cell carcinoma:
- Ultraviolet (UV) exposure. Ultraviolet rays damage the DNA of skin cells and UV radiation is thought to be the major risk factor for most basal cell skin cancers. Sunlight and tanning beds are main sources of UV rays and people with a lot of exposure to light from these sources are at greater risk.
- There are 3 types of ultraviolet rays: UVA, UVB, and UVC
- UVA rays are mainly linked to long-term skin damage such as wrinkles, but are also thought to play a role in some skin cancers.
- UVB rays are the main cause of sunburns. They are also thought to cause most skin cancers.
- UVC rays are not present in sunlight and they do not normally cause skin cancer.
- Light colored skin. The risk of basal cell skin cancer is much higher for whites than for African-Americans or Hispanics, due to the protective effect of the skin pigment melanin found in people with darker skin. Whites with fair skin that freckles or burns easily are at especially high risk.
- Age. The risk of developing basal cell increases with age, most likely because of the buildup of sun exposure over time.
- Gender. Males are about twice as likely as women to develop basal cell skin cancer.
- Exposure to certain chemicals. Exposure to large amounts of arsenic (a heavy metal naturally found in well water in some areas) increases the risk.
- Radiation Exposure. People who have had prior radiation treatment are at a higher risk for developing basal cell carcinoma.
- Previous Skin Cancer. Anyone previously diagnosed with basal cell carcinoma has a higher chance of developing it again.
- Long-term/Severe skin inflammation or injury
- Psoriasis treatment
- Xeroderma pigmentosum. An inherited condition that reduces the skin’s ability to damage DVNA caused by sun exposure.
- Reduced Immune System. The immune system helps the body fight off cancers of the skin as well as other organs. People with weakened immune systems are more likely to develop basal cell carcinoma. Weakened immune systems can be a result of illness such as AIDS or drugs, such as cancer chemotherapy.
- Human Papilloma Virus (HPV) infection. Some HPV types, especially those that people get in their genital and anal area, seem to be related to skin cancers in these areas.
- Leukoplakia. White patches on the tongue, gums, cheeks, or elsewhere inside the mouth have the potential to develop into squamous cell carcinoma. They may be caused by sources of chronic irritation, such as habitual alcohol consumption or tobacco use, or rough edges on teeth or dentures.
- Bowen’s Disease. This is now generally considered an early, noninvasive stage of squamous cell carcinoma. It appears as a persistent red-brown, scaly patch that may resemble psoriasis or eczema. If untreated, it may invade deeper structures. Bowen’s disease is most often caused by exposure to the sun or to arsenic, but other chemical carcinogens, radiation, genetics and trauma also may play a role.
Signs and symptoms
Squamous cell carcinomas may appear as growing lumps, often with a rough, scaly, or crusted surface and can bleed if bumped. They may also look like flat reddish patches in the skin that grow slowly. They often look like warts and sometimes appear as open sores with a raised border and a crusted surface over an elevated pebbly base.
Usually, the doctor’s first step in determining if a patient has skin cancer is taking the patients’ medical history. The doctor will ask when the mark on the skin appeared, if it has changed in size or appearance, and if it has caused any symptoms (pain, itching, bleeding, etc.) During the physical exam, the doctor will note the size, shape, color and texture of the area (or areas) in question, and whether there is bleeding or scaling. The rest of the patient’s body may also be checked for spots and moles that could be related to skin cancer. If the patient is being seen by a primary care physician and skin cancer is suspected, a referral to a dermatologist may be appropriate. If the doctor suspects that a spot on the skin is a squamous cell cancer, the patient will need to have a biopsy, which is the only way to make a definite diagnosis. In this procedure, the doctor tries to remove all of the suspicious-looking growth. There are different ways to do a skin biopsy.
- Shave Biopsy. Doctor will numb the area with a local anesthetic then shave off the top layers of the skin with a small surgical blade.
- Punch Biopsy. A punch biopsy removes a deeper sample of skin. The doctor uses a tool that looks like a tiny round cookie cutter. Once the skin is numbed with a local anesthetic, the doctor rotates the punch biopsy tool on the surface of the skin until it cuts through all the layers of skin.
- Incisional and Excisional Biopsies. An incisional biopsy removes only a portion of the tumor. An excisional biopsy removes the entire tumor. After numbing the area with a local anesthetic, a surgical knife is used to cut through the full thickness of the skin.
A pathologist then examines the tissue under a microscope to check for cancer cells. Sometimes it is helpful for more than one pathologist to check the tissue for cancer cells.
Staging cancer is preferred to determine if a cancer has spread away from where it originally started.
Squamous cell skin cancers is have a small risk of spreading to other organs (though greater than basal cell), so staging may be done, particularly in people who have a high risk of spread. The following stages are used for squamous cell carcinoma:
- Stage 0: Tumor is still confined to the epidermis, the outer most layer of skin
- Stage I: The tumor is 2 cm across or smaller and has none or only 1 high risk feature (see below). It has not spread to the lymph nodes and has not spread to other distant organs
- Stage II: The tumor is larger than 2 cm across or is any size with 2 or more high risk features. It has not spread to the lymph nodes or other distant organs
- Stage III: Tumor has grown into facial bones or has spread into one lymph node less than 3 cm across but has not spread to distant organs.
- Stage IV: Tumor is has grown into the other bones in the body or the base of the skull. The tumor may or may not have spread to distant organs and has spread to nearby lymph nodes.
- Tumor is thicker than 2mm
- Tumor has invaded down into the lower dermis or subcutis
- Tumor has grown into tiny nerves in the skin
- Tumor started on an ear or on non-hair bearing lip
- Tumor cells look very abnormal when seen under a microscope
People with squamous cell carcinoma may be treated by the following:
- Other forms of local therapy
- Radiation therapy
- Systemic chemotherapy
- Targeted therapy
- Simple excision. The skin is first numbed with a local anesthetic. The tumor is then cut out with a surgical knife, along with some surrounding normal skin. The remaining skin is then carefully stitched back together, leaving a small scar.
- Curettage and electrodesiccation. This treatment removes the cancer with a curette (a long, thin instrument with a sharp looped edge on one end), then treating the area with and electric needle to destroy any remaining cancer cells. The process is then often repeated. It will leave a small scar.
- Mohs Surgery. The surgeon removes a very thin layer of the skin (including the tumor) and then checks the sample under a microscope. If cancer cells are seen, the next layer of skin is removed and examined. The process is repeated until the skin samples are found to be free of cancer cells.
- Cyrosurgery. The doctor applies liquid nitrogen to the tumor to freeze and kill the cells.
- Topical Chemotherapy. An anti-cancer medicine is placed directly on the skin rather than being given orally or injected into the vein. Because it is only applied to the skin, the drug does not spread throughout the body, so it doesn’t cause the same side effects that can occur with systemic chemotherapy. It is most often used when the skin cancer is too large for surgery. It is also used when the doctor keeps finding new cancers. Most often, the drug comes in a cream or lotion and is applied to the skin one or two times a day for several weeks. Some examples are fluorouracil (5-FU) and imiquimod. These drugs may cause your skin to turn red or swell. They may itch, hurt, ooze, or cause a rash or sun sensitivity. These skin changes usually go away after treatment is over. Topical chemotherapy usually does not leave a scar. If healthy skin becomes too red or raw when the skin cancer is treated, your doctor may stop treatment.
- Immune Response Modifiers. Drugs are given that can boost the body’s immune system response against the cancer, causing it to shrink and go away.
Radiation therapy (also called radiotherapy) uses high-energy rays to kill cancer cells. The rays come from a large machine outside the body. They affect cells only in the treated area. This treatment is given at a hospital or clinic in one dose or many doses over several weeks. Radiation is not a common treatment for skin cancer. But it may be used for skin cancer in areas where surgery could be difficult or leave a bad scar. You may have this treatment if you have a growth on your eyelid, ear, nose or areas where surgical healing may be impaired. It also may be used if the cancer comes back after surgery to remove it.
Xoft Electronic Brachytherapy (exBx)
One of the biggest benefits to Xoft Electronic Brachytherapy (eBx) is that is it requires fewer sessions than traditional radiation. Treatment for skin cancer can be accomplished in as little as 5 sessions.
Follow-up care after treatment for skin cancer is important. Your doctor will monitor your recovery and check for new skin cancer. New skin cancers are much more common than having a treated skin cancer spread. Between scheduled visits, you should check your skin regularly and contact the doctor if you notice anything unusual. It also is important to follow your doctor’s advice about how to reduce your risk of developing skin cancer again.