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Skin Cancer Screening and Prevention

One of the most common services provided by dermatologists is a general skin examination for skin cancer screening. Dermatologists are specially trained to recognize and manage cancers of the skin. The vast majority of skin cancers fall into one of three categories: basal cell carcinoma, squamous cell carcinoma, and melanoma In addition, dermatologists screen people for precancerous lesions called actinic keratoses.

In the past these skin cancers were mostly a concern for people over the age of 50. However, changing social trends encouraging a more active outdoor lifestyle, and the prevailing misconception that a tan is "healthy", have led to increased sun exposure and, likewise, an increased incidence of these skin cancers in young people. The good news is that most skin cancers can be easily and effectively treated if caught early.

Your skin - more complex than you realize

What is the largest organ in the human body? No, it's not your liver, but rather your skin. Yes, your skin is an organ, just like the heart, lungs, and liver. It is the body's largest organ, in fact, and perhaps its most sensitive. The skin of the average adult covers almost 20 square feet and weighs over 10 pounds. Your skin is not just a simple covering, but it is really a very complex organ in structure and function. Each square inch of skin contains over 30 million cells, numerous sweat glands, thousands of nerve endings, and about 65 hairs.
  • There are three basic layers. Outermost is the waterproof paper-thin epidermis which is contantly renewing itself with cells that migrate up from below. It is this layer which contains melanocytes. Melanocytes produce melanin, a brown-black pigment. The number of melanocytes in a person is determined genetically. People with more melanin have darker skin while those with less have lighter colored skin. The epidermis also grows into fingernails, toenails and hair.
  • The second layer is the dermis or "true skin." The dermis contains a weave of collagen and elastin fibers which allow the skin to stretch and recoil. The dermis also includes blood vessels, lymph vessels, hair follicles, sebaceous glands (which produce oil), and sweat glands. There are also five types of nerve endings in the dermis which sense heat, cold, pain, touch, and pressure.
  • Together, the epidermis and dermis are called the cutaneous layer. Beneath is the subcutaneous layer which specializes in making and storing fat which provides protection and insulation.
The skin has many functions. The most obvious is protection from physical trama, dehydration, ultraviolet radiation, and infection. It also a sentinel providing information about your environment through sensors that detect pain, touch, pressure, heat and cold which link it intimately with the body's control center, the brain. When exposed to sunlight, your skin acts like an endocrine gland producing bone-building vitamin D. Your skin also acts as a thermostat regulating your temperature through your sweat glands. When your body is overheated, sweat is produced which cools the body through evaporation. Recent research suggests that the skin also plays an unsuspected role in activating immune system cells that protect the body from disease. Most of us take our skin for granted - until something goes wrong.

Actinic keratoses

Actinic keratoses are scaly, rough, reddish-brown or yellowish spots on sun-exposed skin of the face and body. These lesions are a direct result of decades of accumulated sun damage. They are considered pre-cancerous lesions by dermatologists, as we know a percentage of these will evolve into actual skin cancers over time.

Fortunately, these lesions can easily be treated in a number of ways. When lesions are distinct and fewer in number, treatment is often by freezing with liquid nitrogen, known as cryotherapy. Patients with numerous lesions can also be treated with topical 5-fluorouracil (5-FU) cream or solution. This method has the advantage of also treating very early areas of sun damage that cannot yet be appreciated. Both treatment options cause the damaged, pre-cancerous areas to peel, leaving healthier skin in its place. Larger, thicker lesions may be biopsied to rule out an evolving skin cancer.

Basal Cell Carcinoma

Basal cell carcinomas (abbreviated as BCC) are the most common type of skin cancer. More than half a million BCCs are diagnosed in the United States yearly. BCCs almost always occur on sun-exposed areas, with the face, ears and neck being the favored sites. They may arise as slow growing, pearly bumps or red scaly patches. Sometimes the lesions bleed easily and form scabs that never quite heal. Most BCCs remain in the area of skin where they arise instead of spreading to other organs. However, they can be very destructive, penetrating to muscle, cartilage or bone depending on the site, if they are left untreated.

Squamous Cell Carcinoma

Squamous cell carcinoma (abbreviated as SCC) are the second most common form of skin cancer. These are also the most common cancer to arise from actinic keratoses, the precancerous lesions mentioned earlier. Like BCCs, SCCs are frequently found on sun-exposed skin, but can develop in protected areas such as the genitals. They usually appear as red scaly patches, or as warty growths. They can also bleed and develop scabs. In rare cases, SCCs can spread to other organs and be fatal if untreated.

Treatment of BCCs AND SCCs

Fortunately, there are a number of treatment options for BCCs and SCCs that can be tailored to the size and location of the lesion, as well as the patient's needs. Early, superficial lesions, particularly those on the trunk and extremities, are frequently treated by a method called electrodessication and curettage. In essence, the cancer cells are literally scraped and burned away leaving a superficial ulcer-like wound that heals over 2-3 weeks with minimal, simple wound care. Superficial lesions can also be treated with aggressive cryotherapy or freezing.

More extensive lesions and those on the face and neck are generally removed by surgical excision. This procedure is mostly performed under local anesthesia while the patient is awake. A specialized form of skin cancer surgery is Mohs surgery performed by specially trained dermatologic surgeons. Mohs micrographic surgery is named in honor of the physician who developed the basic technique, Dr. Frederic Mohs. The main difference between Mohs surgery and other methods of removing skin lesions is microscopic control. In Mohs surgery, multiple thin, horizontal layers of the cancer are removed using local anesthesia. While the patient waits comfortably, that tissue is fixed and examined under the microscope. If skin cancer is detected at the margins, the procedure is repeated until specimens are clear of cancer. Mohs surgery allows the surgeon to remove the entire skin cancer for a cure, while preserving as much skin as possible. This procedure is very useful in areas such as the nose, lips, and ears where we have little skin to spare, and in recurrent skin cancers.

With any form of surgery, once the cancer has been removed, the wound is closed in a straight line, using a flap or graft, or allowed to heal in slowly without stitches. The size of the wound, the cosmetic concern of the location, and the patient's health are all taken into consideration at this stage.

Malignant Melanoma

The number of melanomas diagnosed in the United States each year is growing faster than with any other form of cancer. Over the past two decades, the number of cases in whites has doubled. By the early part of the 21st century, it is predicted that between one in 75 and one in 90 Americans will develop melanoma. These are frightening statistics as melanoma can be deadly if not caught early.

Melanomas often arise as a changing mole or a new mole. Other risk factors include fair skin, a history of multiple sunbums, the presence of numerous large, irregular moles, and a family history of melanoma. Frequent use of tanning beds is also considered a probable risk factor. Despite the frequency of melanoma in fair-skinned people, those with dark skin, including African-Americans, are not completely safe. While sun exposure is a risk factor for melanomas, they can develop anywhere the body produces pigment, including odd sites such as the scalp, eye, inside the mouth, and the bottom of the feet. Early detection of melanoma is crucial for effective treatment. A simple guideline can help a person identify moles of concern. We call this the "ABCDE's of Melanoma":


ABCDE's of Melanoma

Asymmetry
 
Normal moles are usually symmetric, so that one half looks like the other. Melanomas are often asymmetrical
 

Border
 
Normal moles have smooth border. Melanomas often have irregular, scalloped or notched borders.
 

Color
 
Moles that have a variety colors or are much darker than the rest of a person's moles may be worrisome.
 

Diameter
 
Abnormal moles are often larger than 6 mm which is the size of a pencil eraser.
 

Elevation
 
Look for flat moles that become raised
 


Treatment of Malignant Melanoma

If detected in its early, superficial stages, melanoma has a very high cure rate with simple surgical excision alone. Thicker melanomas require surgical removal with larger margins of normal skin. In addition, because of the increased risk of spread to other organs, further labs including a chest x-ray and blood work are done. Another way to monitor for spread of the melanoma is through removal of lymph nodes in the region of the melanoma. Treatment of aggressive melanomas remains a challenge, and research involving trials of chemotherapy medications is very active.

Once someone is diagnosed with melanoma, it is extremely important to have regular skin examinations by an experienced physician to monitor for recurrences or new melanomas. It is also recommended that other family members be checked, as the risk of melanoma can run in the family.

Awareness is low

A high proportion of U.S. residents are unaware of the dangers of melanoma, the deadliest form of skin cancer, according to a survey released by the U.S. Centers for Disease Control and the American Academy of Dermatology Forty-two percent of those surveyed had no knowledge of the disease, with the level of awareness lowest among people ages 18 to 24 years. The survey also found the level of melanoma awareness to be directly related to levels of education and income.

Prevention

While our genetic makeup is beyond our control, one risk factor common to all of the skin cancers mentioned above is sun exposure. Practicing good sun sense can be very important in reducing your risk of skin cancer, especially if begun at a very young age. We now know that 80% of the sun damage we experience in a lifetime occurs before the age of 18. So teaching our children good sun protection can affect their adult health. The basic principles are as follows:
  • Avoid prolonged sun exposure during the times of most intense sun, between lOam and 2pm.
  • Wear your sunscreen daily! Get in the habit of wearing sunscreen, especially on the face, neck and hands, on a daily basis. Many sunscreens come in light moisturizers now, making daily wear more cosmetically acceptable. While we usually worry about getting sunburned at the beach, our skin is constantly barraged by ultraviolet rays during our daily activities, such as driving, walking the dog, running errands, and gardening.
  • On the subject of sunscreens, wear at least an SPF (sun protection factor) of 15. If you would normally start to turn pink in 30 minutes of sun exposure, with a SPF of 15 you would be able to stay out for 15 times that amount of time without burning. However, sunscreen should be reapplied every few hours, especially after water exposure or heavy sweating.
  • Wear a broad spectrum sunscreen, that is one that protects against UVB and UVA rays which are two forms of ultraviolet sun rays that contribute to sun damage.
  • Wear a broad-brimmed hat when spending time outside.
  • Make sure you have appropriate screening by a doctor. If you have multiple risk factors, or are over the age of 55, yearly skin exams are recommended. And, lastly, don't forget to check your own skin on a regular basis!
For more information:

  • Melanoma Patient's Information Page
  • Oncolink: Melanoma
  • Cancer Care: Melanoma


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