Skin cancer is a disease in which malignant (cancer) cells form in the tissues of the skin. The body’s largest organ is the skin. It protects us against infection, injury, sunlight, and heat. It also helps control our body temperature and stores water, fat and Vitamin D. The skin has two main layers: the epidermis and the dermis. The dermis is the lower, inner layer of the skin and the epidermis is the upper, outer layer. It is in the epidermis where skin cancer begins.
Three Kinds of Epidermis Skin Cells
The epidermis is made up of three kinds of skin cells. These include:
- Squamous cells – thin, flat cells that form the top layer of the epidermis
- Basal cells – round cells under the squamous cells
- Melanocytes – skin cells found in the lower part of the epidermis that make melanin (the pigment that gives skin its natural color)
Common Body Areas for Skin Cancer
When we expose our skin to the sun, melanocytes make more pigment, which causes our skin to darken or tan. Skin cancer occurs most commonly in the skin that is frequently exposed to the sun, such as the face, neck, hands and arms. Though these are common areas, remember that skin cancer can occur anywhere on the body.
Types of Skin Cancer
There are different types of cancers that start in the skin. The most common types are basal cell and squamous cell carcinoma, which are both non-melanoma skin cancers. Non-melanoma cancers of the skin rarely spread to other parts of the body. Melanoma, however, is more likely to invade nearby tissue and spread to other places in the body, and it is the rarest of the three common types of skin cancer. Other skin conditions, such as actinic keratosis, can sometimes turn into squamous cell carcinoma.
Risk Factors for Non-Melanoma Skin Cancer and Actinic Keratosis
Skin color and being exposed to sunlight can increase the risk of non-melanoma skin cancer and actinic keratosis. Risk factors are anything that increases your chance of getting a disease. Having a risk factor, or not having any, does not mean that you will or will not get cancer. You should talk to your dermatologist if you feel you may be at risk. The risk factors include:
Basal Cell Carcinoma and Squamous Cell Carcinoma
- Exposure to UV rays – natural or artificial radiation exposure for periods of time
- Fair complexion – having light skin that freckles, burns, and does not tan
- Light eye color – having blue, green or gray colored eyes
- Hair color – having red or blond colored hair
- Actinic keratosis – having existing actinic keratosis lesions of the skin
- Past treatment with radiation – any therapy for previous cancer or excessive X-rays
- Having a weakened immune system – having HIV or other immunodeficiency diseases
- Genes – a family history of skin cancer
- Arsenic exposure – any exposure to this chemical
Actinic Keratosis
- Exposure to UV rays – natural or artificial radiation exposure for periods of time
- Fair complexion – having light skin that freckles, burns, and does not tan
- Light eye color – having blue, green or gray colored eyes
- Hair color – having red or blond colored hair
Signs of Non-Melanoma Skin Cancer and Actinic Keratosis
Non-melanoma skin cancer and actinic keratosis often appear as a change in the skin. Not all changes, though, are a sign of non-melanoma cancer or actinic keratosis. You should check with your doctor if you notice any changes in your skin. Possible signs include:
Non-Melanoma Skin Cancer
- A sore that does not heal
- Areas of the skin that are raised, smooth, shiny, look pearly
- A firm lesion that look like a scar and may be white, yellow or waxy
- A rash that is raised and red or reddish-brown
- Scaly, bleeding or crusty skin
Actinic Keratosis
- A rough, raised and scaly patch on the skin that may be red, brown, or tannish
- A flat scaly, raised discolored skin lesion
- Cracking or peeling of the lower lip that is not helped by lip balm or petroleum jelly
Test and Procedures for Non-Melanoma Skin Cancer and Actinic Keratosis
Dermatologists use tests or procedures to examine the skin, detect abnormalities, and diagnose non-melanoma skin cancer and actinic keratosis. These laboratory and other measures help the doctor determine your exact type of skin problem. These procedures and diagnostic testing options include:
- Skin Exam – Doctor checks the skin for spots/bumps that look abnormal in size, color, shape or texture.
- Conventional Biopsy – All or part of the abnormal area is cut from the skin and viewed under a microscope by a pathologist, who checks for signs of cancer.
- Shaved biopsy – Doctor uses a sterile razor blade to “shave off” the abnormal-looking growth. The specimen goes to a laboratory where a pathologist examines it.
- Punch biopsy – This is a form of biopsy where the dermatologist uses a special instrument (called a punch or trephine) to remove a circle of the tissue from the abnormal growth. The skin tissue is sent to a pathologist for evaluation.
Factors that Affect Prognosis, Recovery and Treatment Options
With non-melanoma skin cancer and actinic keratosis, certain factors affect prognosis, or the chance of recovery, as well as the options for treatment. The prognosis depends mostly on the stage of the cancer or type of skin lesion. Also, the type of treatment used to remove the cancer varies depending on several factors. These treatment options depend on:
- Stage of cancer – whether or not it has spread deep in the skin or to other places in the body
- The type of cancer – different types respond differently to treatment
- Size of the tumor – larger lesions could be more difficult to treat
- Part of the body the cancer affects –spread to lymph nodes or internally
- General health of the patient – immunodeficiency or chronic illnesses
Staging Non-Melanoma Skin Cancer
After the dermatologist diagnoses non-melanoma skin cancer or actinic keratosis, he does more tests to determine whether the cancer cells have spread within the skin or elsewhere in the body. He then can “stage” your skin cancer or actinic keratosis. The staging process helps doctors with the treatment process. This information, gathered from these tests, determines the stage of the cancer. A biopsy is often the only test needed for non-melanoma cancer. But, for squamous cell carcinoma, your doctor may have your lymph nodes checked to see if the cancer has spread.
Three Methods of Metastasis
When non-melanoma cancerous cells break away from the original, primary tumor, and travel to other parts of the body, a secondary tumor could form. This is called metastasis. There are three ways that cancer spreads through the body, or metastasizes. The three methods of metastasis are through:
- Tissue – cancer invades the tissue around the tumor
- The lymph system – cancer invades the lymph ducts and goes to other places in the body
- The blood – cancer invades the capillaries and veins and travels to other parts of the body