Skin Cancer Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

2 main types of skin cancer

A

Keratinocyte skin cancer - basal cell carcinoma and squamous cell carcinoma
Melanoma

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2
Q

Why may the incidence of non-melanoma skin cancer in Scotland be increasing?

A

Cheap air travel
More leisure time
Sun-seeking behaviour
Ageing population

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3
Q

What does melanoma arise from?

A

Melanocytes - pigment forming cells scattered along the basal layer

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4
Q

Which skin cancer is most likely to spread - keratinocyte skin cancer or melanoma?

A

Melanoma as melanocytes migrate into the skin from the neural crest and move around

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5
Q

What does melanoma survival depend on?

A

Breslow thickness

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6
Q

What is Breslow thickness?

A

The measurement of depth of the melanoma from the surface of the skin to the deepest point of the tumour

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7
Q

5 year survival of melanoma with:

  • Breslow thickness <1mm
  • Breslow thickness >4mm
  • Metastases
A
<1mm = 95-100%
>4mm = 50%
Metastases = 5%
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8
Q

Diagnosis of melanoma

A

ABCDE rule
“ugly duckling” sign
Dermoscopy

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9
Q

ABCDE rule in diagnosis of melanoma

A
A = asymmetry
B = border
C = colour (change of colour or presence of 2/3 different)
D = diameter (>0.7mm is likely to be melanoma)
E = evolution (speed of change, changing over weeks/months)
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10
Q

“Ugly duckling sign”

A

The mole suspected as being a melanoma looks very different to all other moles

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11
Q

Why is dermoscopy useful in the diagnosis of melanoma?

A

It allows us to see a magnified view showing pigment pattern

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12
Q

Atypical mole syndrome

A

Genetic condition where patients have multiple atypical moles. These patients are more likely to develop melanoma but are harder to monitor as they have so many moles

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13
Q

Clinical presentation of basal cell carcinoma

A

Slow growing lumps or ulcers that are painless
‘Pearly’ or translucent
Visible, arborising blood vessels
Central ulceration
Locally invasive but rarely metastasise
Can look scar-like with ill-defined edges

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14
Q

Different types of basal cell carcinoma

A

May present as scaly plaque - superficial
Nodular or nodulystic
Infiltrative - “morphoeic”
Pigmented

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15
Q

Clinical presentation of squamous cell carcinoma

A

Hyperkeratotic (crusty) lump or ulcer
Arises on sun damaged skin - often seen in elderly
Grow fairly fast
May be painful and/or bleed

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16
Q

Risk of metastases of squamous cell carcinoma

A

3-5%

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17
Q

Common sites for squamous cell carcinoma (higher risk)

A

Ear, lip, scalp

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18
Q

Keratoacanthoma

A

Self resolving squamous cell carcinoma

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19
Q

Precursor lesions for squamous cell carcinoma

A

Actinic keratosis

Bowen’s disease - carcinoma in situ

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20
Q

Where to squamous cell carcinomas tend to spread to when they metastasise?

A

Lymph nodes and bone

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21
Q

Rarer sites for squamous cell carcinoma

A

Chronic ulceration/wounds/scarring

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22
Q

Actinic keratoses

A

Pre-cancerous skin lesions. Precursors for non-melanoma skin cancers

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23
Q

What do actinic keratoses tell us about the skin?

A

That the skin is damaged

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24
Q

Actinic keratoses are highly associated with the risk of developing what?

A

Squamous cell carcinoma or basal cell carcinoma

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25
Q

What is Bowen’s disease?

A

Carcinoma in situ

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26
Q

Which type of cancer is Bowen’s disease related to?

A

Squamous cell carcinoma

27
Q

Risk factors for skin cancer

A

Sun exposure
Genetic predisposition
Immunosuppression
Other environmental

28
Q

Genetic predisposition conditions that can cause increased risk for skin cancer

A

DNA repair syndromes
Albinism
Naevoid basal cell carcinoma syndrome
Epidermolysis bullosa

29
Q

What is albinism?

A

A congenital absence of melanin.

There is absence or defect of tyrosinase

30
Q

Albinism is autosomal dominant/recessive

A

Recessive

31
Q

Other environmental factors that are risk factors for skin cancer

A
Coal tar
Smoking
Ionising radiation
Arsenic
Trauma
Chronic ulceration
32
Q

Skin cancer prevention

A

Behaviour
Clothing
Sunscreens
Regular self surveillance for early detection

33
Q

Things that fall under behaviour modification in skin cancer prevention

A

Avoid sun in its height (11am-3pm)
Use shade where possible
Particular care of babies/children
Avoid sunbeds

34
Q

Things that fall under clothing modification in skin cancer prevention

A

Tightly woven, loose fitting clothing (dark clothing)

Long sleeves, trousers, skirts, hat, sunglasses

35
Q

Information you should give about sunscreens in skin cancer prevention

A

The sunscreen should be broad spectrum (SPF 30+) with UVA protection
You usually only get a 1/3rd of the protection it says
Application is important - apply twice in sufficient quantities, re-apply after swimming or towelling

36
Q

Oncogene

A

An overactive form of a gene that regulates cell division and drives tumour formation when activity or copy number is increased

37
Q

Proto-oncogene

A

The normal, not yet mutated form of oncogene

38
Q

Tumour suppressor

A

Inactive or non functional form of a gene that negatively regulates cell division. It prevents the formation of a tumour when functioning normally

39
Q

Wavelength of UVB radiation

A

290-320nm

40
Q

What does UVB radiation cause direct damage to?

A

Causes direct DNA damage

41
Q

When is UVB radiation more damaging than UVA radiation?

A

It is 1000x more damaging than UVA when the sun is directly overhead

42
Q

Wavelength of UVA radiation

A

320-400nm

43
Q

What does UVA radiation cause indirect damage to?

A

Causes indirect oxidative damage

44
Q

True or false: UVB radiation penetrates more deeply into the skin than UVA

A

False - UVA penetrates more deeply into the skin than UVB

45
Q

Why are those with skin type I unable to tan?

A

Pheomelanin is produced instead of eumelanin, and pheomelanin absorbs UV less efficiently. Those with skin type I are unable to tan in a protective way

46
Q

Sun exposure patterns

A

> 90% on head, neck, ears, hands, forearms
Outdoor workers
Ageing population
Arises from lifetime cumulative UV exposure

47
Q

What is melanoma and basal cell carcinoma associated with, relating to UV exposure?

A

Associated with intermittent burning episodes

Also associated with subbed use

48
Q

When does up to 80% of sun damage occur?

A

In first 18 years of life

49
Q

Childhood sunburn increases the risk of melanoma by how much?

A

4-fold

50
Q

Pyrimidine dimers

A

UV induced DNA lesions

51
Q

2 types of pyrimidine dimers

A

Cyclobutane pyrimidine dimers and pyrimidine-pyrimidone photo-products

52
Q

Which type of pyrimidine dimer is more common and which is more mutagenic?

A

Cyclobutane pyrimidine dimers are more common

Pyrimidine-pyrimidone photo-products are more mutagenic

53
Q

How are pyrimidine dimers formed?

A

By covalent bonding between adjacent pyrimidines on the same DNA strand

54
Q

How are pyrimidine dimers removed?

A

Nucleotide excision repair

55
Q

Steps of nucleotide excision repair

A
  1. Recognition of the damaged DNA
  2. Cleavage of the damaged DNA on the other side of the photoproduct
  3. DNA polymerase fills the gap, using the undamaged strand as a template
  4. DNA ligase seals the end
56
Q

What happens in UV induced immunosuppression?

Regards to Langerhans cells, T cells and cytokines

A

Depletion of Langerhans cells in the skin and reduced ability to present antigen
Generation of UV induced regulatory T cells with immune suppressive activity
Secretion of anti-inflammatory cytokines by macrophages and keratinocytes

57
Q

Risk factors for UV induced immunosuppression

A

Inflammatory or autoimmune conditions
Immunosuppressants
Organ transplant recipients

58
Q

Which autoimmune conditions can increase risk of UV induced immunosuppression

A

UC - 23% higher risk of melanoma

Crohn’s - 80% higher risk of melanoma

59
Q

Immunosuppressants that can cause IV induced immunosuppression

A

Azathioprine
Cyclosporine
Adalimumab

60
Q

Exposure to which chemical materials can increase the risk of non-melanoma skin cancer?

A
Coal tar pitch
Soot
Creosote
Petroleum products
Shale oils
Arsenic
61
Q

Examples of drugs which are phototoxic

A

NSAIDs
Thiazide diuretics
Anti-TNF
Azathioprine

62
Q

Management of skin cancer

A

Sun protection
Surgery main treatment for skin cancers
Hedgehog inhibitors for BCC
Targeted responses for melanoma

63
Q

Examples of targeted therapies for melanoma

A

Vemurafenib, dabarefenib, MEK inhibitors

64
Q

What is the target for vemurafenib and dabarefinib?

A

Mutated form of B-raf