Skin Cancer Overview and Epidemiology

Question 1

What are the two types of skin cancers?

Answer 1

Melanoma and Non-melanoma cancers (squamous cells and basal cell carcinomas)

Question 2

What proportion of all cancers do skin cancers make up?

Answer 2

1/3 of all cancers

Question 3

What are some reasons for the 334% increase in squamous cell carcinoma in Scotland since 1990?

Answer 3

Cheap air travel, more leisure time, sun-seeking behaviour, ageing population

Question 4

What are some of the reasons for the impact of skin cancers?

Answer 4

Size of the problem
Demographic/behavioural factors
Cost of the problem (30% of hospital appointments for dermatology)
Morbidity and mortality
Lack of effective therapy in aggressive disease

Question 5

What effect does melanoma have on young and middle aged adults?

Answer 5

Causes disproportionate mortality = average of 18.6 years of life lost per melanoma

Question 6

What cells do melanomas arise from?

Answer 6

Melanocytes (pigment forming cells) scattered along the basal membrane

Question 7

Where do melanocytes migrate from?

Answer 7

From the neural crest into the skin (are motile cells that move around, more likely to spread than keratinocyte cancers)

Question 8

What does melanoma prognosis depend on?

Answer 8

Tumour depth:
Breslow thickness < 1mm = 5 year survival of 95-100%
Breslow thickness > 4mm = 5 year survival of 50%
Metastases = 5 year survival is 5%

Question 9

What is the ABCDE rule?

Answer 9

Used to diagnose skin cancers = Asymmetry, Border, Colour, Diameter, Evolution

Question 10

How is atypical mole syndrome useful?

Answer 10

The speed of change in the mole can be a useful red flag

Question 11

How common are basal cell carcinomas?

Answer 11

Around 75% of skin cancers

Question 12

Do basal cell carcinomas tend to spread?

Answer 12

No- they are locally invasive but don’t tend to metastasise

Question 13

What lesions may be a basal cell carcinoma?

Answer 13

Slow growing lumps, non-healing ulcers, rodent ulcer (central ulceration)

Question 14

What are some features of basal cell carcinomas?

Answer 14

Painless (often ignored), pearly or translucent, visible arborising blood vessels

Question 15

What age group tends to get basal cell carcinomas?

Answer 15

> 40’s (but can be in 30s or 40s)

Question 16

What are the different types of basal cell carcinomas?

Answer 16

Superficial (scaly plaque), Nodular/Nodulocystic, Infiltrative (morphoeic), Pigmented

Question 17

How common are squamous cell carcinomas?

Answer 17

About 20% of skin cancers, account for the majority of non-melanoma cancer deaths

Question 18

How do squamous cell carcinomas tend to present?

Answer 18

Warty or crusted lump, ulcer, fast growing, may be painful and bleed

Question 19

Where do squamous cell carcinomas tend to arise?

Answer 19

Sun-damaged skin (lips, ears and scalp particularly high risk)

Question 20

Do squamous cell carcinomas tend to spread?

Answer 20

Yes - may spread if neglected (5 year survival is 25%)

Question 21

What are the precursor lesions of squamous cell carcinomas?

Answer 21

Actinic Keratosis = multiple lesions (also precursor for basal cell carcinoma)
Bowen’s disease = erythematous plaque (carcinoma in-situ)

Question 22

What is the risk of metastases in squamous cell carcinoma?

Answer 22

3-5% (poor prognosis once metastatic)

Question 23

What is a keratocanthoma?

Answer 23

Self-resolving squamous cell carcinoma

Question 24

What are the risk factors for skin cancers?

Answer 24

Sun exposure, genetic predisposition, immunosuppression, other environmental carcinogens

Question 25

What are some conditions that give a genetic predisposition for developing skin cancers?

Answer 25

DNA repair syndromes, albinism, naevoid basal cell carcinoma (Gorlin’s) syndrome, epidermolysis bullosa (especially recessive dystrophic EB)

Question 26

What immunosuppressed groups are at particular risk of developing skin cancers?

Answer 26

Organ transplant recipients, patients with chronic inflammatory diseases (e.g vasculitis, arthritis, IBD), HIV/AIDS, haematological malignancies (e.g chronic lymphocytic leukaemia)

Question 27

What are some other environmental carcinogens that can cause skin cancer?

Answer 27

Ionising radiation, arsenic, coal tar, trauma, chronic wounding, scarring

Question 28

What causes xeroderma pigmentosum?

Answer 28

Defect in one of seven nucleotide excision repair (NER) genes (XPA-G)

Question 29

What are some features of xeroderma pigmentosum?

Answer 29

Photosensitivity, skin cancers on UV exposed skin, neurological degeneration and increased risk of other cancers, 2000-10000 fold increase in skin cancer

Question 30

What is oculocutaneous albinism?

Answer 30

Congenital absence of melanin, absence or defect of tyrosinase

Question 31

What are some features of oculocutaneous albinism?

Answer 31

Autosomal recessive, sun sensitivity and skin cancers, lack of pigment in retina causes visual problems (photophobia, nystagmus, amblyobia)

Question 32

What kind of condition is naevoid basal cell carcinoma (Gorlin’s) syndrome?

Answer 32

Autosomal dominant familial syndrome (1 in 57000)

Question 33

What are the main features of Gorlin’s syndrome?

Answer 33

Early onset, multiple basal cell carcinomas, palmar pits, jaw cysts, ectopic calcification risk

Question 34

What are some minor features of Gorlin’s syndrome?

Answer 34

Skeletal abnormalities, OFC > 97th centile, cardiac or ovarian fibroma, medulloblastoma

Question 35

What causes recessive dystrophic epidermolysis bullosa (RDEB)?

Answer 35

Hereditary type VII collagen deficiency (also know as butterfly’s disease because the skin just crumbles off, most die of squamous cell carcinomas)

Question 36

By how much does having an organ transplant increase your risk of skin cancer?

Answer 36

Squamous cell carcinoma increased 100-200 fold

Basal cell carcinoma increased 5-10 fold

Question 37

What cause “transplant hands”?

Answer 37

Field cancerisation

Question 38

What are some behavioural methods of skin cancer prevention?

Answer 38

Avoid sun at its highest (11am-3pm), use shade where possible, particular care of babies and children, avoid sun beds

Question 39

What clothing helps to prevent skin cancer?

Answer 39

Tightly woven, loose fitting, dark, long sleeves, trousers, skirts

Question 40

How should sunscreen be used to prevent skin cancer?

Answer 40

Broad spectrum (SPF 25+) with UVA protection, application important (twice, sufficient quantities, re-apply after swimming or towelling)