Part 1: Skin Cancer- Epidemiology & Etiology

What is the largest organ of the body?

The skin

The skin measures ____sq feet, and weighs ___ lbs on the average person

22 ft²

10-12 lbs

label

A. Epidermis

B. Dermis

term. dermis

def. the connective tissue layer of the skin

term. epidermis

def. the epithelial layer of the skin

What are the 4 functions of the skin

1. Temperature

2. Barrier

3. Vitamin D

4. External Stimuli Receptors

Skin cancer has a (low/ high) incidence, and an overall (low/high) death rate

high, low

FYI: this is why we leave skin cancer out of cancer statistics

True or False: Skin cancer commonly metastasizes

False, it rarely does

How many cases of skin cancer per year?

Over 1M/ year

Skin Cancer Epidemiology (excluding Melanoma) (4)

• Male predominant (but women have been catching up) FYI: cuz men have outdoorsy jobs, women: tanning

• More common in:

  • fair skin

  • red hair

  • well-freckled people - 10x higher risk of skin cancer

  • people of Irish or Scottish descent

  • people with xeroderma pigmentosum - frequently get skin cancer on exposed surfaces

• Rare in black people

• Peak age is 7th decade in life (people in their 60s)

Why is skin cancer rare in black people?

They have more melanin, which serves as a protectant

If skin cancer does occur in black people, in what areas of the body does it tend to appear? What type of skin cancer is it?

non-pigmented areas

• palms of hands

• soles of feet

• and tends to be a melanoma

What is xeroderma pigmentosum?

genetic condition of pigment abnormalities

Etiology of skin cancer (6)

1. UV radiation

2. Medical radiation- more likely in squamous cell

3. Some chemicals- specially arsenic

4. HPV virus- specially in squamous cells cancers

5. Scars or Chronic Inflammatory Conditions- in squamous cell cancers

6. Genetic disorders including albinism

What is the major risk factor for skin cancer?

UV radiation

Which cancers are more likely to result from radiation exposure?

1. squamous cell cancers

2. basal cell cancers

squamous cell

What is another etiology factor listed in some text books for skin cancers? Why don’t we list it as one?

immune system deficiencies

HOWEVER, immune system deficiencies contribute to ALL CANCERS, it is not specific to skin cancers or any cancer

Which 2 sun components are harmful? Why?

1. UVA- once thought to be harmless. Penetrate deep enough to result in malignant transformations & act as a co-factor, encouraging tumor development initiated by UVB

2. UVB- damages DNA → causing mutations → result in cancer

Tanning beds use (UVA/ UVB) rays

UVA

T/F: A sun burn is the skin’s response to damage, but tanning is not

F: both are a response to damage

T/F: People living in the equator have a higher risk of skin cancer

True

Related to etiology are social/ cultural factors that can cause skin cancer, including:(3)

1. popularization of the “golden tan”

2. Fashion/ clothing trends that allow more skin exposure

3. Depletion of ozone layer allows more UV rays the atmosphere → higher exposure

What prevention program did Australia develop to reduce skin cancer?

Slip, slap, slop

What do the following stand for:

Slip

Slap

Slop

Slip on protective clothing

Slap on a hat

Slop on the sunscreen

SPF stands for

Sun Protection Factor

An SPF of at least ___ is recommended, but anything higher than ___ is trash

15, 25

What does an SPF of 15 mean

with sun protection of 15 SPF, 15 hrs of exposure is equivalent to 1 hr of exposure without sunscreen

How often should you reapply sunscreen?

Every 2 hours &

After swimming or heavy physical activity (Sweating)