Transcript BIOE 301 Skin Cancer

BIOE 301
Skin Cancer
US Skin Cancer: 2004
• ~1,000,000 new cases of basal or
squamous cell carcinoma, and 59,350
new cases of malignant melanoma in
the US in 2004
– Most common cancer in US
• 9,800 deaths in US, 2004
Skin Cancer Around the World
Go To….
The Cancer Atlas: UV Radiation
http://www.cancer.org/downloads/AA/CancerAtlas08.pdf
Who gets Skin Cancer?
• Median age for diagnosis = 57
Age
group
% of
pop.
diagnos
ed
< 20
20-34 35-44 45-54 55-64 65-74 75-84
85+
0.8%
9.4%
5.0%
15.0% 19.4% 17.8% 17.9% 14.8%
– Think you’re safe???
Who gets Skin Cancer?
• Median age for diagnosis = 57
Age
group
% of
pop.
diagnos
ed
< 20
20-34 35-44 45-54 55-64 65-74 75-84
85+
0.8%
9.4%
5.0%
15.0% 19.4% 17.8% 17.9% 14.8%
– Think you’re safe???
“Too Young To Get Skin Cancer? Think again.
When I was only 15 melanoma changed my
life forever” by Jacky Sims
Tune In
• NPR: Rising Rates of Skin Cancer in Young Adults
http://www.npr.org/templates/story/story.php?storyId=4793569
Who is at Risk ?
Although anyone can develop skin cancer, some
people are at particular risk.
Risk factors include:
- Light skin color, hair color, or eye color.
- Family history of skin cancer.
- Personal history of skin cancer.
- Chronic exposure to the sun.
- History of sunburns early in life.
- Certain types of moles or a large number of
moles.
- Freckles, indicate sun sensitivity and www.cdc.gov
sun
damage
Risk to Children
– child's skin is thinner and more sensitive
– frequent sun exposure and sunburn in childhood set
the stage for high rates of melanoma later in life
– Children have more time to develop diseases with
long latency
– Children are more exposed to the sun. Estimates
suggest that up to 80 per cent of a person's lifetime
exposure to UV is received before the age of 18 .
– Children love playing outdoors but usually are not
aware of the harmful effects of UV radiation
UV Indicator
• New Global Solar UV Index
For more information, visit the EPA's UV Index Web site.
Interpret Today’s UV Index
http://www.cpc.ncep.noaa.gov/products/stratosphere/uv_index/gif_files/min2brn.gif
Truths & Myths about Sun
exposure
• 1.You can’t get sunburned on a cloudy day.
• False - Up to 80% of solar UV radiation can penetrate
light cloud cover. Haze in the atmosphere can even
increase UV radiation exposure.
• 2.UV radiation exposure is cumulative during the day
• True!
• 3. A tan protects you from the sun.
• False - A dark tan on white skin only offers an SPF of
about 4.
• 4. A sun tan is Healthy.
• False - A tan results from your body defending itself
against further damage from UV radiation.
www.who.org
Truths & Myths of Sun Exposure
Continued…
• 5. Sunscreens protect me so I can sunbathe much
longer.
• Fasle - Sunscreens are not intended to increase sun
exposure time but to increase protection during
unavoidable exposure.
• 6. Sunburn is caused by UV radiation which cannot be
felt.
• True - Most of the heating is caused by the sun’s visible
and infrared radiation and not by UV radiation.
• 7. Water offers only minimal protection from UV
radiation, and reflections from water can enhance your
UV radiation exposure.
www.who.org
• True!
The Skin
The Skin
Melanocytes and Melanin
•Melanocytes are
cells that produce
Melanin, a pigment
that gives skin, hair,
and eyes their
coloring.
http://www.mayoclinic.com/health/sun-damage/HQ01462
Suntan
• A Suntan results when the
skin increases production
of melanin, in response to
damage caused by UV
light. Melanin absorbs UV
light, and protects the
deeper layers of skin.
• Everytime the skin is
exposed to the sun, ones
lifetime dose of UV
increases. This damage
accumulates, increasing
ones risk for skin cancer.
UV Radiation (UVR)
Sunburn
Penetrating
Penetrating
Rays
Rays
Source:http://www.durascreen-usa.com/info1.asp
What About Tanning Beds?
•Video, CBS News: Teens Hooked On Tanning
Tanning beds emit mainly UVA rays. While they do not cause
sunburn, they are not safe! Research has shown that long term
users have an 8 fold greater chance of developing Melanoma.
Sunburn
•UVA and UVB penetrate the skin, bombarding the
genetic material inside skin cells causing damage.
•Cells do have repair mechanisms that can correct
mutations in the DNA.
•When the damage is overwhelming, cells undergo
apoptosis (cell suicide) causing the skin to peel.
• Damaged cells that are not repaired or killed may
give rise to skin cancer.
•While dark skin may not turn red and blister, damage
to the cells still occurs.
Histology of Skin Cancer
Histology of Skin Cancer
Histology of Skin Cancer
Types of Skin Cancer:
Basal Cell Carcinoma, Squamous
Cell Carcinoma, and Melanoma
Basal Cell Carcinoma
• Most common type of skin
cancer.
• Slow-growing cancer that rarely
metastasizes and is almost
never fatal.
Basal Layer
• Growths begin in the the basal
layer and are made of basal
cells. Basal cells continually
divide to replenish the 2 square
meters of surface skin that is
continually weathering away.
Basal Cell Carcinoma
• Usually develop on sun-exposed areas like the head and
neck.
• Sometimes appear as a red patch of skin or a pearly,
translucent bump. They can also be an irritable open
sore that doesn't heal, or a scar-like lesion.
Squamous Cell Carcinoma
– 2nd most common form
of skin cancer.
– The most common type
of skin cancer in people
with darker skin
– These cancers develop
in higher levels of the
epidermis, where cells
grow tough to protect
the body.
Squamous Cell Carcinoma
– May occur on all parts of the body, including mucus
membranes, but most common on sun exposed
parts of the body (face, neck, hands, shoulder,
arms).
– Can appear as a scaly red patch that sometimes
scabs or bleeds; an open sore that refuses to heal; or
a raised, wart-like growth.
Melanoma
• Melanoma is the most severe skin cancer.
While less common, it occurs at a much
younger age (between 20 and 45 years).
• It is a malignant tumor that originates in
the melanocytes.
• Every blistering sunburn before the age of
18 increases one’s chance of developing
melanoma.
Diagnosis: The ABC’s of
Melanoma
Assymmetry
When half of
the mole does
not match the
other half.
Border
When the
border of the
mole is ragged
or irregular
Color
When the color
of the mole
varies
throughout
Diameter
If the mole’s
diameter is
larger than a
pencil eraser
Progression and 10yr. Survival Rate
in Melanoma.
How Successfully Can We Treat
Skin Cancer?
Non-Melanoma Treatment and Cure Rate
Type of Cancer
Treatment
Basal Cell
Carcinoma
Moh’s micrographic
surgery
Squamous Cell
Carcinoma
Simple Excision
Cure
Rate
99%
95-99%
Mohs Procedure
• http://www.mohscollege.org/mohssurgery.mpg
Melanoma Treatment Options
• Type of treatment depends on stage of
cancer…
• Surgical Excision (always done) via Moh’s
or other method
• Depending on Severity of Cancer
– Removal of Regional Lymph Nodes
– Chemotherapy
– Radiation
Melanoma Survival
Stage I
Stage II
Stage III
Stage IV
Should We Screen?
Conflicting Recommendations..
Opinion of the National Cancer
Institute
• Non-Melanoma and Melanoma Skin Cancer
-Inadequate evidence to determine whether visual
examination of skin in asymptomatic individuals
would lead to a reduction in mortailty.
-Fair evidence that it would have negative and
potentially harmful consequences (unnecessary
surgery).
Clinical Trials
Screening Technology: Dermoscopy
• Simple combination of light
source and magnification
allows for increaseddiagnostic accuracy
• More Advanced Versions
have come available
– SolarScan: Records
Images, computer
analyzes and compares
mole shape and color to
known clinical diagnostic
criteria.
http://www.dermoscopy.org/atlas/base.htm
Above: Basic Dermatoscope
Above: SolarScan
Screening Technology
• MelaFind
– Currently in phase III clinical
trials in the United States
– Produces 10 wavelengths to
penetrate the skin at varying
depths and collect images.
– Looks for disorder among the
skin cells: a characteristic of
cancer
Melafind
References
•
http://www.southeastmissourihospital.com/health/adult/women/skincaus.htm
•
http://www.ehponline.org/members/2003/111-14/innovations.html
•
http://www.smu.org.au/what-is-melanoma-/what-causes-melanoma-.html
• http://www.cancer.org/docroot/AA/content/AA_2_5_9x_Cancer_Atla
s.asp
•
http://www.ehponline.org/members/2003/111-14/EHP111pa770PDF.PDF
•
http://www.aafp.org/afp/20000715/357.html
•
http://www.clevelandclinicmeded.com/diseasemanagement/dermatology/melanoma/t
able1melanoma.htm
•
Project SAFETY Teacher’s Guide. University of Texas MD Anderson Cancer Center.
Ordering information available online at:
http://www.mdanderson.org/departments/projectsafety/