Skip Navigation Links
Centers for Disease Control and Prevention

 CDC Home Search Health Topics A-Z
Office of Surveillance, Epidemiology, and Laboratory Services
EXCITE

EXCITE Home  |  Contact Us
Menu Contents



Science Olympiad» Disease Detectives Event » National Event Exercises
Skin Cancer Module: Practice Exercises



See Also...
Skin Cancer Home
Module 10: Skin Cancers
Module 12: Principles of Prevention
Skin Cancer Glossary
   

On this Page
Objective
Melanoma Rates Are Going Up
Risk Factors for Melanoma
Words to the Wise
Exercise

Module 11:Epidemiology of Melanoma

Objective: Learn more about the current trends in melanoma.

Melanoma is the most serious skin cancer. It can even kill. But melanoma can be prevented. And it can be treated if found early.

Melanoma Rates Are Going Up

In 2001—

  • There were 51,400 new cases of melanoma found in the United States.
  • Melanoma caused about 7,800 deaths in the United States.

The incidence of melanoma has gone up by 4 percent a year since 1973. We don't know all the reasons for this rapid increase. But scientists suspect that the following play an important role:

  • more total exposure to the sun
  • changing patterns of exposure

Incidence by Race and Location

The incidence of melanoma among whites goes up as you get nearer the equator. The world's highest melanoma rate is in Australia. Melanoma is not common in darker-skinned people, such as those of African or Asian background. But darker-skinned people can still get melanoma. They often develop the disease at sites not exposed to the sun. These include the nail beds and soles of the feet.

Back to Top

Risk Factors for Melanoma

There are several known risk factors for melanoma. They include—

  • sun exposure
  • skin type (I, II, III, etc.)
  • skin, hair, and eye color
  • freckling
  • number and type of moles
  • personal and family history

Sun Exposure

There is very strong evidence that sun exposure can cause skin cancer. Ultraviolet (UV) rays damage DNA and cause tumors. But different patterns of sun exposure tend to cause different cancers.

Long-Term Sun Exposure Vs. Short "Bursts"
Squamous cell carcinomas are linked to total sun exposure over time. But melanomas and, more recently, basal cell carcinomas are linked to "short, intense exposure."

Squamous cell carcinomas usually occur in skin areas that get the most sun over long periods of time. Examples are the face and back of the hands and forearms. Basal cell carcinomas usually occur on the face, but recently, more and more are showing up on areas that are not chronically exposed to the sun. On the other hand, melanoma usually appears in areas exposed to the sun intensely for short periods. Examples are the trunk in males and the lower legs in females. Melanoma is also more common in people who get sun only in intense bursts on weekends and vacations.

Back to Top

How the Incidence of Skin Cancer Depends on the Pattern (short bursts or over a long period of time) and the Amount of Exposure

Graphs
[ Text Description ]

Reprinted from the Journal of Photochemistry & Photobiology B, Vol 63, 2001, pp 8-18, Armstrong: "The epidemiology of solar radiation and skin cancer", figure 5, with permission from Elsevier Science.

Skin Type, Coloring, Freckling, and Moles

Physical traits linked with a higher risk for melanoma include—

  • fair skin
  • skin that burns easily
  • light eyes (blue/green/gray)
  • blond or red hair
  • freckling

Having a lot of moles can also raise risk. This is especially true if you have any oddly shaped moles. Moles are also called "nevi." Oddly shaped nevi are referred to as "atypical." Most moles develop from sun exposure in childhood. So having a lot of moles may mean that you got a lot of sun as a young child. About 40 percent of melanomas begin in existing moles. So checking moles for the "ABCDs" of melanoma is an important step toward early detection. (The ABCDs of melanoma were covered in module 10. They are Asymmetry, irregular Border, uneven Color, and Diameter larger than a pencil eraser.)

To see some examples of "benign," or non-cancerous, nevi and melanoma, go to http://www.skincarephysicians.com/melanomanet/skin_lesions.htm.*

Personal and Family History

You have a higher risk of melanoma if you or someone in your family has ever had the disease.

Back to Top

Words to the Wise

Some very important risk factors for melanoma can be changed. You can lower risk by preventing—

  • unprotected sun exposure, especially intense, "off and on" exposure
  • sunburns early in life

Just a few bad sunburns in childhood or young adulthood can raise your risk for melanoma. We are all born with physical traits that we can't change. But we can change what we do. You can reduce your risk of melanoma by protecting yourself from the sun's ultraviolet rays.

Exercise

Go back to the Web site http://seer.cancer.gov to see how the incidence of melanoma has gone up over the last 25 years.

Step 1: From the "Choose a Cancer Site" pop-up menu, choose "Melanomas of the Skin."
Step 2: Under "Incidence," find "Line Charts Displaying Age-Adjusted (1970 U.S. Standard Population) SEER Incidence Rates for Individual Years: Nine Registries for 1973-1998."
Step 3: Click on rates for [All Ages] by Sex, then by Race, then by Race and Sex. In what groups have the incidence rates gone up? Why do you think so?

Back to Top

Back to Skin Cancer Home





This page last reviewed April 24, 2007

EXCITE Home | Contact Us
CDC Home | Search | Health Topics A-Z
Privacy Policy | Accessibility

United States Department of Health Human Services
Centers for Disease Control and Prevention
Office of Surveillance, Epidemiology, and Laboratory Services
Scientific Education and Professional Development Program Office