Skin Cancer

Guide I-106
Bruce Jacobs, Ph.D., Extension Health Specialist
Robert J. Segal, M.D., Fellow, American Academy of Dermatology
College of Agriculture, Consumer and Environmental Sciences New Mexico State University. (Print Friendly PDF)

Skin cancer is the most common type of cancer in the United States. It develops when skin cells become damaged beyond repair, and cancer cells form. When these cancer cells multiply, a tumor or abnormal growth of tissue develops.

Three Major Types of Skin Cancer

Three types of skin cancer comprise more than 99 percent of all skin cancers and are named based on the type of skin cell they develop from: (1) basal cell carcinoma (BCC) from the basal cell, (2) squamous cell carcinoma (SCC) from the squamous cell, and (3) melanoma from the melanocytes. BCC and SCC are also called non-melanoma skin cancers. For all of these skin cancers, the cure rate is always higher if detected and treated early. Also, early treatment is much simpler, less invasive and less expensive.

Basal Cell Carcinoma (BCC) is the most common skin cancer (making up about 8 of every 10 cases). Most of the time BCC occurs on areas of the body exposed to the sun, such as the scalp, ears, nose, neck, shoulders and back. While it rarely spreads to other parts of the body, basal cell carcinoma can damage and disfigure surrounding skin.

Possible signs:

  • Small raised bump that looks smooth, shiny and translucent
  • A small, pink, crater-like growth with a raised, rolled border and an indentation in the center
  • A scar-like area that is white, yellow or waxy
  • Reddish irritated patches of skin
  • A sore that does not heal

Squamous Cell Carcinoma (SCC) is the second most common type of skin cancer. Out of 100 cases of skin cancer, about 15 will be SCC. As with basal cell carcinoma, squamous cell carcinoma most frequently occurs on areas of the body exposed to the sun. It can, however, occur on other parts of the body including inside the mouth. SCC can spread and become fatal.

Possible signs:

  • A crusty wart-like growth
  • A raised growth with a depression in the center
  • Scaly red-patched area
  • A sore that does not heal

Melanoma is the third most common type of skin cancer occurring in about 5 of every 100 cases of skin cancer. Most skin cancer deaths are due to melanoma. It’s the most lethal skin cancer because it can very quickly spread in the body to internal organs and throughout the lymphatic system, a major part of the body’s immune system. An increased survival rate is directly related to early detection and treatment. Not all melanomas are sun-related and can develop on parts of the body not exposed to the sun.

Possible signs:

  • Most melanomas are black like the color of a watermelon seed
  • Flat or slightly elevated discolored patch (tan, brown, red, black, blue or white)
  • Black or brown discoloration (usually under the nails, on the soles of the feet or palms of the hands)
  • A bump that is usually black, but can be blue, gray, white, brown, tan, red
  • Change on the skin such as (1) a new spot developing or (2) a change in size, shape or color of an existing spot or mole

In 2005 in the United States, it is estimated that more than 1 million new cases of basal cell and squamous cell cancers and 59,580 cases of melanoma will occur (this statistic does not include very early stage melanoma). It’s also estimated that 7,770 people in the United States will die from melanoma this year. That’s one person dying from this cancer approximately every hour.

Sun Exposure: The Leading Cause of Skin Cancer

Overexposure to the sun’s ultraviolet (UV) rays damages skin cells and is the leading cause of skin cancer. Therefore, it is critically important to protect yourself from cumulative exposure to the sun.

New Mexico has factors that increase exposure to UV rays: high elevation; clear skies; and a high, reflective desert. On a mid-summer day, a fair-skinned person can get sunburned within nine minutes. New Mexico’s year-round warm climate increases people’s time outdoors and prompts the use of less clothing–increasing exposure to the sun.

Fortunately, there are various steps you can take to protect yourself from the sun’s UV rays:

  • Wear a wide-brimmed hat that protects your scalp, eyes, ears, face and neck
  • Wear wrap-around sunglasses that provide “100% UV protection”
  • Always use a broad-spectrum sunscreen with a sun protection factor (SPF) of 30 or higher (see product label), even on cloudy days; apply generous amounts and reapply every two hours (more often after swimming or other exercise)
  • Limit time in the sun when rays are strongest (between 10 a.m. and 4 p.m.)
  • Seek shade (especially when you can’t see your shadow, or when your shadow’s length is less than your height)
  • Avoid getting sunburned
  • Wear clothes with a tight weave that cover your skin (look for “sun protective” clothing and laundry-treatment products made specifically for protection against UV rays; check with your dermatologist about these products)
  • Avoid deliberate tanning in the sun
  • Do not use tanning beds and sunlamps, as these also emit UV radiation
  • Protection from the sun should begin in childhood

Risk Factors for Skin Cancer

  • Family or personal history of skin cancer
  • A history of sun exposure (for example: outdoor employment, tanning)
  • A history of severe, blistering sunburn(s), particularly in childhood or teenage years
  • Sun sensitivity (sunburning easily)
  • While people of all colors can develop skin cancer, light-skinned people, especially those who freckle easily, are at higher risk
  • Men are slightly more likely to develop skin cancer than women
  • Living in geographic locations that are exposed to high levels of the sun’s UV rays, such as New Mexico
  • A suppressed immune system caused by immunosuppressive medications or immune compromising diseases
  • Specific to non-melanoma: occupational exposure to chemicals such as arsenic, industrial tar, coal, paraffin, and mineral oils; exposure to radiation treatment
  • Specific to melanoma: having many moles or having large (pencil-eraser sized) moles

Prevention and Early Detection are Vitally Important!

Taking preventive action against the harmful effects of UV rays is a major step to significantly decreasing the risk of skin cancer. Additionally, early detection of signs of skin cancer is crucial for preventing its spread. See a dermatologist immediately if you recognize any possible signs of skin cancer.

How To Do a Skin Self-Exam*

You can improve your chances of finding skin cancer promptly by performing a simple skin self-exam regularly.

The best time to do this self-exam is after a shower or bath. You should check your skin in a well-lighted room using a full-length mirror and a hand-held mirror. It’s best to begin by learning where your birthmarks, moles, and blemishes are and what they usually look like. Check for anything new–a change in the size, texture, or color of a mole, or a sore that does not heal.

Check all areas, including the back, the scalp, between the buttocks, and the genital area

  1. Look at the front and back of your body in the mirror, then raise your arms and look at the left and right sides.
  2. Bend your elbows and look carefully at your palms; forearms, including the undersides; and the upper arms.
  3. Examine the back and front of your legs. Also look between your buttocks and around your genital area.
  4. Sit and closely examine your feet, including the soles and the spaces between the toes.
  5. Look at your face, neck, and scalp. You may want to use a comb or a blow dryer to move hair so that you can see better.

By checking your skin regularly, you will become familiar with what is normal. If you find anything unusual, see your doctor right away. Remember, the earlier skin cancer is found, the better the chance for cure.
*From the National Cancer Institute (


  • American Academy of Dermatology
  • American Cancer Society
  • Centers for Disease Control and Prevention
  • National Cancer Institute
  • Skin Cancer Foundation

Information Disclaimer
The information provided in this publication is only intended to be general summary information to the public. The primary purpose of this publication is educational. Nothing contained in this publication is, or should be considered or used, as a substitute for medical advice, diagnosis or treatment.

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Printed and electronically distributed July 2005, Las Cruces, NM.