1. State/National Statistics: Basic Epidemiology of Skin Cancer
Presented by: Chris Johnson, MPH
Epidemiologist, Cancer Data Registry of Idaho
Cancer Awareness, Screening, and Prevention Alliance (CASPA)
May 18th, 2010 7-8:30 a.m.
Huckleberry Room
Central District Health Department. 

2. Outline Skin Skin Cancer SCC and BCC Melanoma Melanoma Risk Factors
Incidence
Stage
Survival
Mortality
Lifetime Risks
Prevention

3. The Skin
The skin is the body’s largest organ. It protects against heat, sunlight, injury, and infection. It helps regulate body temperature, stores water and fat, and produces vitamin D.
The skin has two main layers: the outer epidermis and the inner dermis.
For skin cancer, we are chiefly interested in cells of the epidermis, which include:
Squamous cells
Basal cells
Melanocytes

4. The Skin
The epidermis is mostly made up of flat, scale-like cells called squamous cells. Round cells called basal cells lie under the squamous cells in the epidermis. The lower part of the epidermis also contains melanocytes.
Melanocytes produce melanin, the pigment that gives skin its natural color. When skin is exposed to the sun, melanocytes produce more pigment, causing the skin to tan, or darken.
Sometimes, clusters of melanocytes and surrounding tissue form noncancerous growths called moles.

5. Skin Cancer Cancer may develop in any of the cell types:
Squamous Cell Carcinoma (SCC)
Basal Cell Carcinoma (BCC)
Melanoma
Skin cancer is the most common form of cancer in the United States.

6. Squamous and Basal Cell Carcinomas
The American Cancer Society estimates that substantially more than 1 million unreported cases of basal cell and squamous cell cancers occur annually in the US. This number is roughly equivalent to the total of all other cancer sites.
Death rates from basal cell and squamous cell carcinomas are low.
When detected early, approximately 95% of these carcinomas can be cured.
However, these cancers can cause considerable damage and disfigurement if they are untreated.
Basal cell and squamous cell carcinomas are more than 10 times as common as melanoma but account for less morbidity and mortality.
SCC may account for 20% of all deaths from skin cancer.
SCC and BCC are not reportable to CDRI unless regional or distant stage or on a mucous membrane.
There were 5 reportable SCC and BCC skin cases in 2007 in Idaho.
We do not know how many total cases of SCC and BCC there are per year in Idaho, but estimate it to be over 5,000.
Why don’t we collect data on SCC and BCC?
They are highly curable
This would not be a good use of resources.
Collection of these cases is not required by SEER, NPCR, COC.
The highest rates in the world are found in Queensland, a northerly province of Australia, where a population of largely English and Irish extraction is exposed to very high natural UV radiation levels

7. Melanoma
Melanoma occurs when melanocytes (pigment cells) become malignant.
Most melanocyte cells are in the skin; when melanoma starts in the skin, the disease is called cutaneous melanoma.
Melanoma may also occur in the eye (ocular melanoma or intraocular melanoma).
Rarely, melanoma may arise in the meninges, the digestive tract, lymph nodes, or other areas where melanocytes are found.
Skin melanoma usually begins in a mole.
It can occur on any skin surface.
In men, melanoma is often found on the trunk or the head and neck.
In women, it often develops on the lower legs.

8. Melanoma of the Skin
Melanoma is one of the most common cancers and the most serious type of cancer of the skin.
Melanoma accounts for less than 5% of skin cancer cases but causes a large majority (about 75%) of skin cancer deaths.
The American Cancer Society estimates that about 68,720 new cases of malignant melanoma will be diagnosed in 2009, and 8,650 will die from the disease in the US.
In some parts of the world, especially among Western countries, melanoma incidence is on the rise.
In the United States, melanoma incidence has more than doubled in the past 30 years.
All in situ and invasive melanoma cases are reportable to CDRI.
Collectively, BCC, SCC and Melanoma will claim the lives of about 11,000 Americans this year.

9. Melanoma Risk Factors Light skin color, hair color, or eye color.
Rates are more than 10 times higher in whites than in African Americans.
Family history of skin cancer.
Personal history of skin cancer.
Intermittent exposure of untanned skin to intense sunlight.
Severe (blistering/peeling) sunburns early in childhood.
Presence of atypical or numerous moles (greater than 50).
Freckles, which indicate sun sensitivity and sun damage.
I am a poster child for melanoma risk factors.
… check, … check
Studies have found the following risk factors for melanoma:
Dysplastic nevi: Dysplastic nevi are more likely than ordinary moles to become cancerous. Dysplastic nevi are common, and many people have a few of these abnormal moles. The risk of melanoma is greatest for people who have a large number of dysplastic nevi. The risk is especially high for people with a family history of both dysplastic nevi and melanoma.
Many (more than 50) ordinary moles: Having many moles increases the risk of developing melanoma.
Fair skin: Melanoma occurs more frequently in people who have fair skin that burns or freckles easily (these people also usually have red or blond hair and blue eyes) than in people with dark skin. White people get melanoma far more often than do black people, probably because light skin is more easily damaged by the sun.
Personal history of melanoma or skin cancer: People who have been treated for melanoma have a high risk of a second melanoma. Some people develop more than two melanomas. People who had one or more of the common skin cancers (basal cell carcinoma or squamous cell carcinoma) are at increased risk of melanoma.
Family history of melanoma: Melanoma sometimes runs in families. Having two or more close relatives who have had this disease is a risk factor. About 10 percent of all patients with melanoma have a family member with this disease. When melanoma runs in a family, all family members should be checked regularly by a doctor.
Weakened immune system: People whose immune system is weakened by certain cancers, by drugs given following organ transplantation, or by HIV are at increased risk of developing melanoma.
Severe, blistering sunburns: People who have had at least one severe, blistering sunburn as a child or teenager are at increased risk of melanoma. Because of this, doctors advise that parents protect children’s skin from the sun. Such protection may reduce the risk of melanoma later in life. Sunburns in adulthood are also a risk factor for melanoma.
Ultraviolet (UV) radiation: Experts believe that much of the worldwide increase in melanoma is related to an increase in the amount of time people spend in the sun. This disease is also more common in people who live in areas that get large amounts of UV radiation from the sun. In the United States, for example, melanoma is more common in Texas than in Minnesota, where the sun is not as strong. UV radiation from the sun causes premature aging of the skin and skin damage that can lead to melanoma. Artificial sources of UV radiation, such as sunlamps and tanning booths, also can cause skin damage and increase the risk of melanoma. Doctors encourage people to limit their exposure to natural UV radiation and to avoid artificial sources.

10. Ultraviolet Radiation
These risk factors pertain to UV light exposure.
This is how things work:
From nuclear fusion, radiation , or sunlight, shoots out form the sun towards the surface of the earth.
The ozone layer, a thick concentration of O3 molecules, absorbs some radiation in the ultraviolet (UV) spectrum, preventing it from reaching the earth’s surface.
Under a clear sky at noon, up to 0.5% of the energy reaching the surface of the earth from the sun consists of biologically active UV-B radiation. The absolute intensity is primarily controlled by the sun's angle so that, during winter or in the morning and evening, it is only a small fraction of that at noon in summer. Ozone (O3) is very rare in the earth’s atmosphere – about 3 ppm. Most of it is located between 12 and 18 miles above the surface. Stratospheric ozone (sometimes referred to as "good ozone") absorbs most of the biologically damaging ultraviolet sunlight (UV-B), allowing only a small amount to reach the Earth's surface. Many experimental studies of plants and animals and clinical studies of humans have shown the harmful effects of excessive exposure to UV-B radiation.
EARTH SURFACE

11. UV Radiation Wavelengths
Ultraviolet radiation (or UV radiation)— Electromagnetic radiation with wavelengths between 100 and 400 nanometers. These rays are emitted from the sun and are not visible. They inflict increasingly more damage upon a recipient as the wavelength decreases. Based on its effects, UV radiation is subdivided into three wavelength ranges named UV-A, UV-B and UV-C:
UV-A covers the wavelength range nm. UV-A is not absorbed by the ozone layer. UV-A are present with relatively equal intensity during all daylight hours throughout the year, and can penetrate clouds and glass. Does not cause sunburn, does cause tanning. Recent research suggests its role in melanoma.
UV-B covers the wavelength range nm. UV-B is more energetic than UV-A, and is partially absorbed by the ozone layer. UV-B rays cause sunburn, tanning, and have been shown to cause SCC and BCC. UV-B also has the beneficial effect of vitamin-D production.
UV-C covers the wavelength range nm. UV-C is the most dangerous form of UV radiation, but is completely absorbed by the ozone layer. Artificial UV-C (for example emitted by electric discharges) is a threat for certain occupational group, like welders.
At high noon, ultraviolet radiation reaching ground level is 95% UVA and 5% UVB, while before 10am and after 2pm this percentage changes over time to 99% UVA and 1% UVB.

12. UV Exposure
More than 90% of skin cancers in the US are attributed to UV-B exposure.
Other causes of skin cancer include arsenic, other chemical exposures.
Human exposure to UV-B depends upon an individual's
location (latitude and altitude)
the duration and timing of outdoor activities (time of day, season of the year = angle of the sun)
and precautionary behavior (use of sunscreen, sunglasses, or protective clothing).
UV exposure in childhood and intense intermittent UV exposures are the major environmental risk factors for melanoma and BCC, and cumulative UV exposure is the major preventable risk factor for SCC.

13. UV Exposure From NOAA Climate Data.
The UV Index is a measure of total ultraviolet radiation, and not just Vitamin D-producing UVB.

14. Mean UV by County * AVGLO units = watt-hours per square meter (Wh/m2).
† AVGLO source: Tatalovich Z, Wilson JP, Cockburn M. A comparison of thiessen polygon, kriging, and spline models of potential UV exposure. Cartogr Geogr Info Sci 2006; 33(3):

15. Ozone Layer Depletion
Is ozone loss to blame for the melanoma upsurge in the US and Europe?
Unlikely:
UV-B has not yet increased much in the US and Europe.
Melanoma takes years to develop. There hasn't been enough time for ozone depletion to play a significant role.
Current and future increases in UV radiation exposure due to ozone depletion will exacerbate the trend toward higher incidence of melanoma.
First of all, UV-B has not, so far, increased very much, at least
in the US and Europe.
Second, melanoma takes years to develop. There hasn't been
enough time for ozone depletion to play a significant role.
Third, the melanoma epidemic has been going on since the 1940's.
Recent increases in rates may just reflect better reporting, or
the popularity of suntans in the '60's and '70's. (This becomes
more likely if UV-A is in fact involved.)

16. UV-B Exposure - Sunburn
33.7% of U.S. adults report having had a sunburn in 2004 (BRFSS).
In Idaho, 48.4% of white adults reported having had a sunburn in 2008.
Parents or caregivers reported that 72% of adolescents aged years have had at least one sunburn, and 43% of white children aged <11 years experienced a sunburn in the past year.
A substantial segment of the adult population is not consistently practicing sun-protection behaviors.
None of the states with sunburn prevalence among whites greater than 45% were traditional "sunbelt" states. Persons living in the northern states might use fewer precautions during the first sunny days after winter or might travel to other locations where they acquire sunburns. States with lower UV radiation (i.e., those in higher latitudes) have had more rapid increases in melanoma incidence than states with higher UV radiation.

17. Sunburn
Sunburn prevalence varies somewhat by Health District in Idaho.

18. Sunburn
Among adults in Idaho, sunburn varies considerably by age. Younger people are much more likely to burn.

19. Synopsis of Melanoma in Idaho
In 2007, there were 341 invasive cases of melanoma and 43 melanoma deaths among Idaho residents.
Melanoma is the 5th most common cancer in Idaho in terms of incidence and 16th most common site for cancer deaths.
Those are the risk factors. Now we will get into melanoma statistics.

20. Melanoma Incidence 2007
There were 6,823 invasive cases of cancer diagnosed among Idaho residents in (5.0% of the total) were melanoma.
In Health District 4, there were nearly 100 new cases of invasive melanoma in 2007.

21. Top 10 Cancer Incidence - Males
Of 3,623 cancer cases among males in Idaho, 2007, 197 (5.4% of total) were melanoma.

22. Top 10 Cancer Incidence -Females
Of 3,200 cancer cases among females in Idaho, 144 (4.5% of total) were melanoma.

23. Incidence by Race/Ethnicity
Melanoma rates vary considerably by race/ethnicity. Rates in whites are more than 10 times higher than among blacks. The variation is mostly due to the protective effects of skin pigmentation.

24. Incidence by Age
Incidence rates increase sharply with age, and males have higher rates than females.
The area of the graph that shows higher rates among females in age groups has been attributed by some to be related to tanning bed usage.
The elderly (especially elderly men) bear a disproportionate burden of morbidity and mortality from melanoma and nonmelanoma skin cancer. Men older than age 65 account for 27% of all newly diagnosed cases (in both sexes) of malignant melanoma and women in the same age group account for 15%.

25. Incidence of Invasive Melanoma by Site on Body and Sex, United States, 2004—2006
Melanomas occur on different parts of the body for males and females. This is likely due to intermittent intense exposures.
Data are from population-based cancer registries that participate in the National Program of Cancer Registries (NPCR) and/or the Surveillance, Epidemiology, and End Results (SEER) Program and meet high-quality data criteria (see Table 1 for a list of registries). These registries cover 77.6% of the population for
Rates are per 100,000 population and are age-adjusted to the 2000 US standard population (19 age groups; Census P ; see Day ).

26. This map shows incidence rates of melanoma by state for the latest available year (2006). Idaho ranked 11th among whites from

27. This map shows melanoma rates by county for 1998-2007
This map shows melanoma rates by county for The counties with dashed lines had fewer than 10 cases and thus unstable rates. Some of the variation in rates is likely due to incomplete reporting of melanomas to CDRI by non-hospital sources. This is a known problem in US registries, but Idaho appears to have better reporting overall than most states.
Ada and Valley Counties had high rates.

28. SEER Summary Staging 2000
Cancer staging is the process of describing the extent of the disease or the spread of the cancer from the site of origin.
In situ – noninvasive; basement membrane of epidermis is intact (Clark’s level I)
Localized – papillary/reticular dermis invaded (Clark’s level II-IV)
Regional – subcutaneous tissue invaded (Clark’s level V), satellite nodules <= 2 cm from primary tumor, regional lymph nodes involved
Distant – extension to underlying cartilage, bone, skeletal muscle, metastasis to skin or subcutaneous tissue beyond regional lymph nodes or visceral metastasis
AJCC Stages of Melanoma
The following stages are used for melanoma:
Stage 0: In stage 0, the melanoma cells are found only in the outer layer of skin cells and have not invaded deeper tissues.
Stage I: Melanoma in stage I is thin:
The tumor is no more than 1 millimeter (1/25 inch) thick. The outer layer (epidermis) of skin may appear scraped. (This is called an ulceration).
Or, the tumor is between 1 and 2 millimeters (1/12 inch) thick. There is no ulceration.
The melanoma cells have not spread to nearby lymph nodes.
Stage II: The tumor is at least 1 millimeter thick:
The tumor is between 1 and 2 millimeters thick. There is ulceration.
Or, the thickness of the tumor is more than 2 millimeters. There may be ulceration.
Stage III: The melanoma cells have spread to nearby tissues:
The melanoma cells have spread to one or more nearby lymph nodes.
Or, the melanoma cells have spread to tissues just outside the original tumor but not to any lymph nodes.
Stage IV: The melanoma cells have spread to other organs, to lymph nodes, or to skin areas far away from the original tumor.
In a study of Florida melanoma cases, late-stage diagnosis was more common among patients who were male, unmarried, smokers, and who lived in communities with low median incomes and education levels.

29. Incident Cases by Stage
The distribution by stage is very similar between Idaho and the U.S.
There are about 6 times as many early stage cases than late stage.

30. Melanoma Trends
Early stage incidence rates increased about 3.8% per year in SEER regions from 1973 to Late stage incidence rates increased about 3.2% per year during the same period. The ratio of early to late stage cases has increased somewhat over time, but has generally remained about 6 early stage cases to 1 late stage case.

31. Trends
Some experts say the rise in incidence reflects a true increase in the disease, while others contend it is an artifact of more intensive recent surveillance. Some experts suggest that the rise in melanoma incidence may in part reflect longer life expectancy as well as efforts to detect melanoma earlier.
The incidence of thin invasive lesions is increasing faster than that of thick ones, which reflects earlier detection by physicians and greater public awareness of warning signs of skin cancer.
The incidence and mortality rates of melanoma have increased during the past several decades in the United States. Among the reasons for these trends, increased exposure to UV radiation as a result of lifestyle changes is generally recognized as an important factor.

32. Incidence Trends
The incidence of melanoma of the skin increased at a rate of about 3.5% per year in Idaho from 1975 to The rate of increase was higher for males (4.1% per year) than for females (2.8% per year), and rates of melanoma incidence among males were higher than among females. The incidence of in-situ melanoma of the skin increased at a higher rate (9.2% per year from 1980 to 2007) than for the invasive cases depicted in the graph. The trends for Idaho and SEER Whites are very similar, with Idaho rates showing more variation due to smaller numbers of cases.

33. Melanoma Incidence Rates By Stage and State, Grouped into Low, Medium, and High Tertile Groups, 2004—2006
This figure shows melanoma incidence rates for states in 3 tertiles based on low, medium, or high rates of early stage melanoma by state. Although early stage rates vary widely, late stage rates are similar. This is evidence supporting problems with reporting of early stage melanomas in some state cancer registries.
Data are from population-based cancer registries that participate in the National Program of Cancer Registries (NPCR) and/or the Surveillance, Epidemiology, and End Results (SEER) Program and meet high-quality data criteria (see Table 1 for a list of registries). These registries cover 77.6% of the population for
Rates are per 100,000 population and are age-adjusted to the 2000 US standard population (19 age groups; Census P ; see Day ).

34. Cancer Survival
Cancer is not a death sentence. Overall, across all sites, 5-year relative cancer survival is about 66%.
Among cancers, survival from melanoma is quite good: about 88%.

35. Melanoma Survival by Stage
Survival depends greatly upon the stage of disease at the time of diagnosis.
Idaho has lower stage-specific melanoma survival rates than SEER regions. This was true even when limited to Ada County.
5-year relative survival for localized cases was about 94% for Idaho cases and 99% for SEER.
5-year relative survival for regional cases was about 54% for Idaho cases and 66% for SEER.
5-year relative survival for distant cases was about 12% for Idaho cases and 16% for SEER.

36. Melanoma Mortality
There were 10,931 deaths among resident Idahoans in 2008, 2,503 of which were cancer. There were 50 melanoma deaths in Melanoma constituted 2.0% of cancer deaths and 0.5% of total deaths in Idaho in 2008.
From , there were 226 melanoma deaths in Idaho, 62 among residents of Health District 4.

37. Leading Causes of Mortality and Melanoma - Males
In 2008, there were 5,522 deaths among male Idahoans. These included 1,308 cancer deaths, 33 of which were melanoma. Among males, melanoma deaths were 2.5% of all cancer deaths, and 0.6% of all deaths. Note that for the first time, in 2008 cancer was the leading cause of death in Idaho. This was true for both males and females.

38. Leading Causes of Mortality and Melanoma - Females
In 2008, there were 5,409 deaths among female Idahoans. These included 1,195 cancer deaths, 17 of which were melanoma. Among females, melanoma deaths were 1.4% of all cancer deaths, and 0.3% of all deaths.

39. Patterns in Melanoma Mortality
Melanoma mortality in the US reflects the relationship between UV radiation levels in each geographic region, the sun-protection behaviors of each generation of males and females in each age group, the geographic mobility of the population, and risk awareness and early detection.

40. This map shows melanoma mortality for 2002-2006 by state
This map shows melanoma mortality for by state. Idaho has among the highest rates of melanoma mortality.

41. Mortality Trends
Rates of melanoma mortality have also increased over time, but at a much slower rate than the incidence rates. In the US, melanoma mortality has increased about 52% since about 1.0% per year. The Idaho rates are very similar, but show much variation due to the smaller numbers of deaths per year.

42. Risks of Developing and Dying from Melanoma
The lifetime risk of developing melanoma in the US was 1 in 1,500 in Today, it is 1 in 45.
The lifetime risk for dying of melanoma is 0.46% in US white men and 0.23% in US white women.
These tables come from the latest annual report of the Cancer Data Registry of Idaho and use incidence and mortality data. The report is available at idcancer.org.
Source: SEER Cancer Statistics Review

43. Risks of Developing and Dying from Melanoma

44. Preliminary Results from CDC Melanoma Monograph
Many papers, many authors
A few preliminary results:
Socio-economic status (SES)
Physician per county population
Relationship to incidence differs by stage at time of diagnosis
As a bonus, I wanted to cover some information from a CDC-led monograph on melanoma that I am working on.

45. Melanoma & SES
SES measures contribute substantially to variation in cutaneous melanoma incidence and mortality.
Patients with higher SES measures are more likely to be diagnosed with melanoma.
However, patients with lower SES measures are more likely to have an advanced stage at diagnosis, and worse outcomes, including higher mortality.
Complex relationship between:
socioeconomic factors, environmental risk factors and sun exposure behavior,
awareness of melanoma prevention, access to primary care and melanoma screening,
potential variation in ultraviolet exposure related to differences in outdoor recreation and leisure, a product of SES itself.
The relationship between melanoma and socio-economic status is the strongest among any cancer site.

46. Melanoma & SES
93% of cases were among non-Hispanic whites, so the results are for this race/ethnicity group.
Results from the multilevel Poisson regression models for early and advanced stage melanoma incidence for non-Hispanic whites. For the early stage models, counties with higher high school education, lower poverty, higher median household income, and lower unemployment showed higher incidence rates. County urbanicity was not statistically significant.
In the late stage model, no SES variable had significant effects at the county level.

47. Melanoma & SES
In the late stage model, no SES variable had significant effects.

48. Melanoma & Physician Density
Having more dermatologists, internists, and general practitioners per population in the county increased the incidence of early stage melanoma.
For internists and GPs, an additional physician per 10,000 population increased the early stage incidence of melanoma by less than 1%. Increasing the number of dermatologists by one per 10,000 increased the early stage incidence of melanoma by about 14%. Note, however, that the numbers of primary care physicians and dermatologists are shown on the same scale (per 10,000), which is not appropriate.
Having more dermatologists, internists, or general practitioners per population in the county did not increase the incidence of late stage melanoma.

49. Prevention of Melanoma
Primary Prevention
Avoiding the disease in the first place
Secondary Prevention
Screening
Early diagnosis and treatment

50. HP 2010 Objectives
Objective 3-9: Increase to 75% the proportion of persons who use at least one of the following protective measures that may reduce the risk of skin cancer:
avoid the sun between 10 a.m. and 4 p.m.
wear sun-protective clothing when exposed to sunlight
use sunscreen with a sun-protection factor (SPF) of 15 or higher
and avoid artificial sources of ultraviolet light
Objective 3-8: Reduce melanoma deaths to 2.5 per 100,000 population
3-8.
Reduce the rate of melanoma cancer deaths.
Target: 2.5 deaths per 100,000 population.
Baseline: 2.8 melanoma cancer deaths per 100,000 population occurred in 1998 (age adjusted to the year 2000 standard population).
Target setting method: 11 percent improvement.
Data source: National Vital Statistics System (NVSS), CDC, NCHS.
Total Population, 1998
Melanoma Cancer Deaths
Rate per 100,000
TOTAL
2.8
Race and ethnicity
American Indian or Alaska Native
DSU
Asian or Pacific Islander
0.3
Asian
DNC
Native Hawaiian and other Pacific Islander
Black or African American
0.5
White
3.1
Hispanic or Latino
0.8
Not Hispanic or Latino
2.9
3.3
Gender
Female
1.8
Male
4.1
Education level (aged 25 to 64 years)
Less than high school
High school graduate
2.7
At least some college
2.3
DNA = Data have not been analyzed. DNC = Data are not collected. DSU = Data are statistically unreliable. Note: Age adjusted to the year 2000 standard population.
3-9.
Increase the proportion of persons who use at least one of the following protective measures that may reduce the risk of skin cancer: avoid the sun between 10 a.m. and 4 p.m., wear sun-protective clothing when exposed to sunlight, use sunscreen with a sun-protective factor (SPF) of 15 or higher, and avoid artificial sources of ultraviolet light.
3-9a.    (Developmental) Increase the proportion of adolescents in grades 9 through 12 who follow protective measures that may reduce the risk of skin cancer.
Potential data source: Youth Risk Behavior Surveillance System (YRBSS), CDC, NCCDPHP.
3-9b.    Increase the proportion of adults aged 18 years and older who follow protective measures that may reduce the risk of skin cancer.
Target: 75 percent of adults aged 18 years and older use at least one of the identified protective measures.
Baseline: 47 percent of adults aged 18 years and older regularly used at least one protective measure in 1998 (age adjusted to the year 2000 standard population).
Target setting method: Better than the best.
Data source: National Health Interview Survey (NHIS), CDC, NCHS. Data on artificial ultraviolet light source are developmental.
Persons Aged 18 Years and Older, 1998 (unless noted)
Type of Protective Measure
3-9b. Regularly Used at Least One Protective Measure
Limited Sun Exposure*
Wore Protective Clothing*
Used Sunscreen*
Percent 47 28 24 31 48 26 44 34 25 22 23 50 39 17 37 12 49 41 30 27 32 35 54 33 40
Education level (aged 25 years and older) 29 45
Some college
Family income level
Poor 43 19
Near Poor 46
Middle/high income 51
Geographic location
Urban
Rural
Disability status
Persons with activity limitations
57 (1992)
38 (1992)
33 (1992)
27 (1992)
Persons without activity limitations
53 (1992)
31 (1992)
28 (1992)
29 (1992)
DNA = Data have not been analyzed. DNC = Data are not collected. DSU = Data are statistically unreliable. Note: Age adjusted to the year 2000 standard population. *Data for limited sun exposure, used sunscreen, and wore protective clothing are displayed to further characterize the issue.

51. Primary Prevention
Skin cancer is largely preventable when sun protection measures against UV rays are used consistently.
Preventing sunburn, especially in childhood, may reduce the lifetime risk for melanoma.
Recommendations:
Avoid exposure to the midday sun (from 10 a.m. to 4 p.m.) whenever possible. When your shadow is shorter than you are, remember to protect yourself from the sun.
If you must be outside, wear long sleeves, long pants, and a hat with a wide brim.
Protect yourself from UV radiation that can penetrate light clothing, windshields, and windows.
Protect yourself from UV radiation reflected by sand, water, snow, and ice.
(23). National surveys indicate that only one third of Americans practice sun-protective behaviors, and their practices vary greatly, depending on age, sex, and their ability to tan and burn (9,12,13).
Preventive strategies include reducing sun exposure (e.g., by wearing protective clothing and using sunscreen regularly), avoiding sunlamps and tanning equipment, and practicing skin self-examination. Help protect your skin by using a lotion, cream, or gel that contains sunscreen. Many doctors believe sunscreens may help prevent melanoma, especially sunscreens that reflect, absorb, and/or scatter both types of ultraviolet radiation. These sunscreen products will be labeled with “broad-spectrum coverage.” Sunscreens are rated in strength according to a sun protection factor (SPF). The higher the SPF, the more sunburn protection is provided. Sunscreens with an SPF value of 2 to 11 provide minimal protection against sunburns. Sunscreens with an SPF of 12 to 29 provide moderate protection. Those with an SPF of 30 or higher provide the most protection against sunburn.
Wear sunglasses that have UV-absorbing lenses. The label should specify that the lenses block at least 99 percent of UVA and UVB radiation. Sunglasses can protect both the eyes and the skin around the eyes.
There is little direct evidence, however, that any of these interventions reduce skin cancer morbidity or mortality.

52. Primary Prevention
Only one third of adults reported that they use sunscreen, seek shade, or wear protective clothing when out in the sun.
Adolescents aged years were found to routinely practice sun-protective behaviors slightly less than adults (using sunscreen (31%), seeking shade (22%), and wearing long pants (21%).
Among children aged <11 years, sunscreen use (62%) and shade seeking (26.5%) were the most frequently reported sun-protective behaviors.
Young people have moderate to high awareness of skin cancer but are unaware of the connection between severe sunburns and skin cancer; sunburns, although considered painful and embarrassing, are not perceived as a health threat.

53. Findings of the Task Force on Community Preventive Services on Reducing Exposure to Ultraviolet Light
The Task Force recommends two interventions:
educational and policy approaches in primary schools --- changing children's covering-up behavior (wearing protective clothing); and
educational and policy approaches in recreational or tourism settings --- changing adults' covering-up behaviors.
The recommended interventions had small to moderate behavior change scores in studies:
In primary schools, the median net relative increase was 25% (interquartile range: 1%--40%, six studies).
In recreational settings, the median net relative increase was 11.2% (interquartile range: 5.1%--12.9%, five studies).
It should be noted that the interventions were targeted to populations rather than single persons. Small changes in behavior in large populations can result in substantial public health benefits.

54. Sunscreen
Sunscreen's role in preventing skin cancer has been demonstrated to be complex.
Using sunscreen has been shown to prevent squamous cell and basal cell skin cancers.
Sunscreens May Not Reduce the Risk of Cutaneous Melanoma
The evidence for the effect of sunscreen use in preventing melanoma is mixed.
The conflicting results may reflect the fact that sunscreen use is more common among fair-skinned people, who are at higher risk for melanoma;
or, this finding may reflect the fact that sunscreen use could be harmful if it encourages longer stays in the sun without protecting completely against cancer-causing radiation.
Some sunscreens only protect against UVB radiation.
Sunscreen also blocks vitamin D formation in the skin, a process that some researchers believe also promotes cancer.
To date, no criteria exist in the U.S. for measuring and labeling the amount of UVA defense a sunscreen provides. However, the FDA plans to introduce UVA standards within the next few years.
Sunscreen does not appear to be effective against melanoma because sunscreen use has been associated with more childhood sunburns, a risk factor for melanoma. This is attributed to people using sunscreen to enable them to spend more time in the sun, thereby increasing the risk of sun damage.
Epidemiologic studies suggest that sunscreen use could be considered harmful if it increased a person's total time in the sun and total UV exposure. Partly for that reason, sunscreen use alone might not protect against melanoma despite its protective effect on SCC. The International Agency for Research on Cancer (IARC) recommends that sunscreens not be used as the sole method for skin cancer prevention and not be used as a means to extend the duration of UV exposure (21).
Sunscreens probably prevent squamous-cell carcinoma of the skin when used mainly during unintentional sun exposure. No conclusion can be drawn about the cancer-preventive activity of topical use of sunscreens against basal-cell carcinoma and cutaneous melanoma. Use of sunscreens can extend the duration of intentional sun exposure, such as sunbathing. Such an extension may increase the risk for cutaneous melanoma (26).
Daily sunscreen use on the hands and face reduced the total incidence of squamous cell cancer in a randomized trial of 1,621 residents in Australia (rate ratio [RR]: 0.61; 95% confidence interval [CI] = ) (9). Sunscreen had no effect on basal cell cancer. Based on this trial, 140 people would need to use sunscreen daily for 4½ years to prevent one case of squamous cell cancer. An earlier randomized trial demonstrated that sunscreen use reduced solar keratoses, precursors of squamous cell cancers (10). There are no direct data about the effect of sunscreen on melanoma incidence. An unblinded randomized trial showed that children at high risk for skin cancers who used sunscreen developed fewer nevi than those who did not. Several epidemiologic studies have found higher risk for melanoma among users of sunscreens than among nonusers (11--13). A recent meta-analysis of population-based case-control studies found no effect of sunscreen use on risk for melanoma (14).
The evidence is clear that exposure to solar UV-B affords protection against numerous cancers, and that current public health recommendations that advocate little or no sunlight exposure should be revisited – especially since the adverse health effects of vitamin D deficiency are not limited to cancer, but also appear to include type 1 diabetes, multiple sclerosis, rheumatoid arthritis, cardiovascular disease, and osteoporosis.

55. Sunscreen Controversy
Many do not block UVA radiation, which does not cause sunburn but can increase the rate of melanoma, so people using sunscreens may be getting too much UVA without realizing it.
Additionally, sunscreens block UVB, and if used consistently this can cause a deficiency of vitamin D.
Even some products labeled "broad-spectrum UVA/UVB protection" do not provide good protection against UVA rays.
The best UVA protection is provided by products that contain zinc oxide, avobenzone, and ecamsule.

56. Recent Sunscreen Research
A recent meta-analysis found consistently that sunscreen users above 40 degrees latitude are at a higher risk of melanoma than people who don't use sunscreen, even when differences in skin color are taken into account.
Wearing sunscreen decreased melanoma risk in studies closer to the equator.
In the Northern hemisphere, 40 degrees draws a line between New York city and Beijing.
The UV light that reaches the Earth's surface is composed of UVA (longer) and UVB (shorter) wavelengths. UVB causes sunburn, while they both cause tanning. Sunscreen blocks UVB, preventing burns, but most brands only weakly block UVA. Sunscreen allows a person to spend more time in the sun than they would otherwise, and attenuates tanning. Tanning is a protective response (among several) by the skin that protects it against both UVA and UVB. Burning is a protective response that tells you to get out of the sun. The result of diminishing both is that sunblock tends to increase a person's exposure to UVA rays.
It turns out that UVA rays are more closely associated with melanoma than UVB rays, and typical sunscreen fails to prevent melanoma in laboratory animals.
Modern tanning beds produce a lot of UVA and not much UVB, in an attempt to deliver the maximum tan without causing a burn. Putting on sunscreen essentially does the same thing: gives you a large dose of UVA without much UVB.
The authors of the meta-analysis suggest an explanation for the fact that the association changes at 40 degrees of latitude: populations further from the equator tend to have lighter skin. Melanin blocks UVA very effectively, and the pre-tan melanin of someone with olive skin is enough to block most of the UVA that sunscreen lets through. The fair-skinned among us don't have that luxury, so our melanocytes get bombarded by UVA, leading to melanoma. This may explain the incredible rise in melanoma incidence in the US in the last 35 years, as people have also increased the use of sunscreen. It may also have to do with tanning beds, since melanoma incidence has risen particularly in women.

57. Ultraviolet-B (UVB)-vitamin D-cancer hypothesis
UVB-induced vitamin-D may decrease the rates of some cancers.
Several ecological and observational studies have examined the hypothesis, in addition to one good randomized, controlled trial.
Results for breast and colorectal cancer satisfy the criteria best, but there is also good evidence that other cancers do as well, including bladder, esophageal, gallbladder, gastric, ovarian, rectal, renal and uterine corpus cancer, as well as Hodgkin's and non-Hodgkin's lymphoma.
Several cancers have mixed findings with respect to UVB and/or vitamin D, including pancreatic and prostate cancer and melanoma. Even for these, the benefit of vitamin D seems reasonably strong.
The action spectrum of ultraviolet radiation mainly responsible for melanoma induction is unknown, but evidence suggests it could be ultraviolet A (UVA), which has a different geographic distribution than ultraviolet B (UVB).
The evidence is fairly clear that exposure to solar UV-B affords protection against numerous cancers, and that current public health recommendations that advocate little or no sunlight exposure should be revisited – especially since the adverse health effects of vitamin D deficiency are not limited to cancer, but also appear to include type 1 diabetes, multiple sclerosis, rheumatoid arthritis, cardiovascular disease, and osteoporosis.

58. Sun Exposure: UV-B
A number of public health organizations state that there needs to be a balance between having the risks of having too much (skin cancer) and the risks of having too little sunlight (vitamin-D deficiency).
There is a general consensus that sunburn should always be avoided.
However, not all physicians agree with the assertion that there is an optimal level of sun exposure, with some arguing that it is better to minimize sun exposure at all times and to obtain vitamin D from other sources.
Serum levels of 25(OH) D3 are below the recommended levels for a large portion of the general adult population and in most minorities, indicating that Vitamin D deficiency is a common problem in the United States.

59. Tanning Beds
Tanning beds primarily emit UVA. The lamps used in tanning salons emit doses of UVA as much as 12 times that of the sun.
Use of sunbeds (with deeply penetrating UVA rays) has been linked to the development of skin cancers, including melanoma.
In July 2009, the IARC released a report that categorized tanning beds as “carcinogenic to humans.” The agency, which is part of the World Health Organization (WHO), previously classified tanning beds as “probably carcinogenic.” The change comes after an analysis of more than 20 epidemiological studies indicating that people who begin using tanning devices before age 30 are 75% more likely to develop melanoma.
The World Health Organization recommends that no person under 18 should use a sunbed.

60. Secondary Prevention
Self Skin Examinations
Medical Skin Examinations

61. Signs and Symptoms: ABCD
Asymmetry Border
Color Diameter

62. Cost-Effectiveness of Screening for Malignant Melanoma
Journal of the American Academy of Dermatology. 41(5, Part 1): , November 1999.
The cost-effectiveness ratio for a screening program of adults older than age 20 who were at high risk for skin cancer was about $30,000 per year of life saved.
This is reasonably cost-effective compared with other accepted cancer screening strategies.

63. National Melanoma/Skin Cancer Detection and Prevention Month
May is National Melanoma/Skin Cancer Detection and Prevention Month. This month is dedicated to increasing public awareness of the importance of skin cancer prevention, early detection, and treatment, including basal cell, squamous cell, and melanoma. 

64. CDC Resources CDC recommends easy options for sun protection1—
Use sunscreen with sun protective factor (SPF) 15 or higher, and both UVA and UVB protection.
Wear clothing to protect exposed skin.
Wear a hat with a wide brim to shade the face, head, ears, and neck.
Wear sunglasses that wrap around and block as close to 100% of both UVA and UVB rays as possible.
Seek shade, especially during midday hours.

65. NCI Resources

66. NCI Resources

67. CDC Resources

68. That concludes my talk about state and national skin cancer statistics.
More info is available at
Questions?