What is skin cancer?
Skin cancer is a collective term for a variety of types of cancer that affect the skin, lips, eyelids, and nails. The majority of cases of skin cancer are the result of ultraviolet (UV) exposure. All types of skin cancers have very high cure rates and excellent outcomes when detected early. Although the number of skin cancers is increasing, studies have shown skin cancers are now being diagnosed at earlier stages and at smaller sizes. As a result, one of the main missions of a dermatologist is to detect skin cancer early and prevent spread to other areas of the body.
The most common type of skin cancer is called basal cell carcinoma (BCC), which affects over two million Americans a year. It affects both men and women and occurs most commonly on skin surfaces exposed to excessive ultraviolet light such as the face, scalp, ears, neck, chest, hands, and forearms. This type of skin cancer is slow growing and rarely spreads to internal organs. The second most common skin cancer is squamous cell carcinoma (SCC) and affects about 700,000 Americans a year. Like BCCs, SCCs most commonly occur on sun-exposed skin. Although rare, large SCCs have the potential to spread to lymph nodes and internal organs. Together BCCs and SCCs are known as non-melanoma skin cancer (NMSC).
Melanoma is a less common form of skin cancer with 75,000 new diagnoses every year in the U.S.. Melanoma derives from the skin cells that make pigment called melanocytes. Melanoma has an extremely high cure rate if it is found early while the cancer is limited to the most superficial layer of the skin (or <1 mm of skin invasion). However, melanoma can spread quickly in the body if it becomes spreads to the deeper layers of then skin. Sadly, one American dies hourly from melanoma, and the risk of melanoma increases by 75% with a history of indoor tanning.
What are the signs and symptoms?
Any skin cancer can caused mild pain or bleeding, but these symptoms are often absent in the very early stages skin cancer. BCCs most commonly appear as a shiny, pink or red, raised bump on the skin surface. It may have an appearance of a large acne lesion, but unlike acne, it doesn’t heal within a month of its appearance. BCCs develop on sun exposed skin surfaces such as the face, scalp, ears, neck, chest, hands, and forearms. SCCs typically have a hard, crusted or scaly, pink to red-colored appearance. In women, a common area for developing SCCs is on the lower legs. Melanomas often have one or more features of the “ABCDE rule” and can appear on ANY surface of the skin. In women, melanoma occurs most frequently on their backs and legs. The “ABCDE rule” includes the following:
A = asymmetry, the appearance of the lesion looks different from left to right or top to bottom
B = borders are irregular or jagged
C = colors that are varied, with hues of black, dark brown, blue, white, or red
D = diameter greater than 6 mm
E = evolution or changingWhat are the risk factors?
The most common risk factors for skin cancer include sun exposure, indoor or outdoor tanning, previous sunburns, positive family history, more than 50 moles, long-term exposure to x-rays, and a history of smoking. In addition, patients with a decreased ability to tan such as those with pale skin, blue, green, or grey eyes, and/or red or blonde hair are at increased risk for skin cancer. However, skin cancer occurs in ALL skin colors and on ALL surfaces of the body. Occasionally we will see skin cancer develop in a non-healing open sore (ulcer), in the scar of a third degree burn, or in a patient with a history of a weakened immune system. Finally, scientists have recently found a few genes associated with both melanoma and breast cancer; CDK2NA and BRCA2.
How is it diagnosed?
The diagnosis of skin cancer often begins with a skin check by a board certified dermatologist. The idea of a skin check can seem a little intimidating, but let me reassure you that your doctor will treat you and your skin with the upmost respect. For a full body skin check, you will be asked to change into a gown and then your dermatologist will check your skin surface from the scalp to the tip of your toes. I typically start the exam by checking areas such as the hands and arms, followed by the legs. It is my way to slowly introduce patients to the skin check by first checking areas that you most commonly show in clothing. I will often use a drape or sheet to carefully drape the areas I am looking at so my patients do not feel as exposed. I also chat with my patient about their family, work, the weather, etc., in order to help put them more at ease.
During your exam, your dermatologist will look at your normal moles and check for any irregularities based on the ABCDE rule above. They will also check for skin cancer and may ask you questions about a particular lesion they find. These questions include “How long has a lesion has been present?” and “Does it have any symptoms?” If a lesion looks suspicious, your dermatologist may choose to do a skin biopsy. The word biopsy often sounds scary when patients first hear it. However, in most cases only a small piece of skin about the size of a pencil eraser is removed. The procedure is done in the office with a small amount of injectable, local anesthesia, called lidocaine with epinephrine, to keep you comfortable during the procedure. If you are pregnant or breastfeeding, your doctor may choose to use lidocaine without epinephrine as it is a class B medication and will be safe for your baby. This skin tissue is removed, sent to a laboratory for processing, and then examined under a microscope in order to obtain a diagnosis.
For Part 2 of the Skin Cancer Series click here!
1. American Academy of Dermatology: www.aad.org
2. American Society of Dermatologic Surgery: www.asds.net
3. Lee KC, et al. Safety of cosmetic dermatologic procedures during pregnancy. Dermatol Surg. 2013 Nov;39(11):1573-86.