Skin Cancer Flashcards
What are the 2 main types of skin cancer?
Melanoma and keratinocyte (non-melanoma) skin cancers
What are the 2 types of keratinocyte/non-melanoma skin cancers?
Basal cell carcinomas (BCC)
Squamous cell carcinomas (SCC)
Which cells do the following skin cancers originate from?
- Basal Cell Carcinoma
- Squamous Cell Carcinoma
- Melanoma
BCC -> cells in the basal layer of the epidermis
SCC -> suprabasal cells in the epidermis
Melanoma -> melanocytes in the basal layer of the epidermis
Skin cancer is the second most common human cancer. T/F?
False
It is the most common (1/3 of all cancers)
Which of the 2 main types of skin cancer is the most common?
Keratinocyte (non-melanoma) -> makes up >90% of skin cancers
Incidence of both melanoma and keratinocyte/non-melanoma skin cancer is increasing. T/F?
True
Keratinocyte is incidence increasing the most
What are benign collections of melanocytes called?
Melanocytic naevi or moles
Why are melanomas more likely to metastasize than keratinocyte cancers? (2)
Melanocytes are motile cells that move around
Metastatic melanomas respond poorly to chemo and radiotherapy
Which cancer treatments are most useful for melanomas?
Targeted therapy and immunotherapy
What is the most important prognostic factor for melanoma survival?
Tumour depth
What is Breslow’s Thickness?
A measurement of depth of a melanoma vertically from the top of the granular layer to the deepest point of tumour involvement
What is the 5-year survival for a melanoma with…
- Breslow’s thickness <1mm
- Breslow’s thickness >4mm
- Metastases
Breslow’s thickness <1mm -> >95%
Breslow’s thickness >4mm -> 50%
Metastases -> 5%
What is the ABCDE rule for diagnosing a melanoma early?
Asymmetry Border (irregular) Colour (irregular) Diameter Evolution
Why is the ‘evolution’ of ABCDE so important?
Normal moles change slowly over years whereas melanomas evolve rapidly over several weeks or months
What is the ‘ugly duckling’ sign of a melanoma?
A mole that looks different from all the others
What is atypical mole syndrome?
A genetic condition where family members have a large number of moles which are hard to monitor
What surveillance technique is recommended for families with atypical mole syndrome?
Mole mapping (regular photographing) to observe for rapidly changing moles
What are the differences in the patient groups most likely to be affected by BCC and SCC?
BCC -> younger patients (~40y/o) with intermittent episodes of severe sunburn e.g., annually on holidays
SCC -> older patients with cumulative sun damaged skin
Which keratinocyte skin cancer is most likely to metastasize?
SCC
BCC can be locally invasive but don’t usually spread
BCC is usually treated successfully with…
Surgical excision
Which keratinocyte skin cancer grows faster?
SCC
What is the most common type of BCC? Describe its appearance
Nodular/ nodulocystic BCC
A well-defined, raised nodule which is…
- Shiny
- Translucent
- Has telangiectasia
Describe the appearance of these less common forms of BCC…
- Rodent ulcer
- Superficial
- Morphoeic (infiltrative)
- Pigmented
Rodent ulcer -> ulcer with a shiny, telangiectasic border
Superficial -> similar to a small patch of dermatitis, makes it hard to diagnose
Morphoeic (infiltrative) -> looks like a scar with an ill-defined border
Pigmented -> resembles a melanoma
What are the most common clinical presentations of a SCC? (2)
A hyperkeratotic (crusted) lump or an ulcer
Name 2 precursor lesions for SCC (carcinoma-in-situ)
Actinic keratoses
Bowen’s disease
What is keratoacanthoma?
An unusual form of SCC which grows for around 3 months and then self-resolves
What are the highest risk sites for SCC?
Ear (most likely to metastasize)
Lip
Scalp
Where do SCCs most commonly metastasize to?
Regional lymph nodes (most common)
Bone
Keratinocyte skin cancers may also arise in areas of…
Chronic ulceration, scarring or burns
Actinic keratoses are very common. T/F?
True
1/3 of men in the UK >70y/o have them
Describe the appearance of actinic keratoses
Multiple small, red and scaly patches of skin found on sun-exposed areas of skin
Actinic keratoses are strongly associated with risk of developing SCC only. T/F?
False
It is associated with high risk of developing both SCC and BCC
Describe the appearance of the lesions in Bowen’s disease
An erythematous plaque, often found as a single lesion on the leg
Describe the histology of Bowen’s disease
Shows full thickness epidermal dysplasia but no invasion into the dermis
Bowen’s disease is strongly associated with risk of developing SCC only. T/F?
True
What are Bowenoid actinic keratoses?
Multiple actinic keratoses which have full thickness epidermal dysplasia
What are the 4 main categories of risk factors for developing a skin cancer?
- Sun exposure/ skin type
- Genetic susceptibility
- Immunosuppression
- Other environmental carcinogens
What is xeroderma pigmentosum?
A genetic disease characterised by a defect in 1 of the 7 nucleotide excision repair (NER) genes
Why is xeroderma pigmentosum strongly associated with skin cancer?
Defect in NER genes means that DNA damage caused by UV exposure is unable to be repaired