Skin Cancers Flashcards
What are 3 examples of skin cancers?
- Basal cell
- squamous cell
- melanoma
What are 3 examples of skin cancers?
- Basal cell
- squamous cell
- melanoma
What is basal cell carcinoma (BCC)?
what / where does it arise from?
a slow-growing and locally-invasive skin cancer that arises from the pluripotent cells of the stratum basale layer of the epidermis.
How common is BCC compared to other skin cancers? How likely is it to metastasise?
- MOST COMMON skin cancer
- LEAST likely to metastasise
- lifetime risk of 23-39% in caucasians
RF for BCC?
- long-term UV exposure i.e. childhood sunburn
- UVA therapy for psoriasis
- Fitzpatrick type 1 skin
- immunosuppression (e.g. transplant patients have a 10-fold increased risk)
- Genetic syndromes (such as Xeroderma Pigmentosa or Gorlin syndrome)
UV exposure leads to genetic mutations in DNA (specifically on the p53 tumour suppressor )
Clincial features of BCC
where?
how present? charachter? onset? any other skin symptoms ?
- on sun-exposed areas of the head and neck, with the remainder mainly occurring on the trunk or lower limbs.
- small slow-growing lesions
- raised pearly edges
- evident telangiectasia.
Other symptoms:
* Initially - no
* IF LEFT -pain, bleeding, and ulceration, or subsequent local invasion into surrounding tissues.
Subtypes of BCC?
changes how they present
- Nodular
* most common 50-60%
* i.e. pink pearly nodule with talangiectasia
* can ulcerate / crusty - Superficial 10-15%
* erythematous scaly plaques with a thread like border
* may ulcerate / bleed - Morphoeic
- Basosquamous
Differentials for BCC?
- Trichoepithelioma ( rare benign tumour of the hair follicle)
- Keratoacanthoma (rapidly-growing tumour of the skin derived from the glands surrounding a hair follicle)
- Squamous Cell Carcinoma.
Investigations for BCC?
Dermatoscope examination
* see features making diagnosis likely e.g. (such as arborising vessels, spoke wheel like structures, areas of ulceration).
- Often no other investigations needed unless signs of invasion of other underlyinf structures or mets - need radiological imaging
- Diagnosis confirmed through a biopsy e..g excision biopsy
What factors guide how a BCC is managed?
i.e. tumour subtype
- tumour subtype
- size
- anatomical location
- histological diagnosis
Compare and contrast a Low-risk BCC to a high risk BCC
Low-risk BCCs:
* small
* well-circumscribed lesions
* superficial type lesions
* do not meet any of the high-risk criteria
High-risk BCCs:
* young (<25yrs) or immunocompromised patients
* Recurrent lesions
* lesions on the nose, lips, ears, or around the eyes
* lesions with poorly defined margins
* All non-nodular subtypes of BCC
What are some non surgical management options for BCC?
(often good for superficial BCCs *)
- Cryotherapy (or CO2 ablation)
- Curettage and electrodissection
- Immune response modulator e.g. Topical imiquimod 5% cream* 5 days a week for 6 weeks
- Topical chemotherapy – 5-fluorouracil 5% cream* once daily for 2 weeks
- Photodynamic therapy – light therapy together and topical photosensitising agent*
- Radiotherapy – e.g. older patients
Surgical management for BCCs?
Excision biopsy
* margins 3-5mm (depends on border and location of lesion - 5mm margin if reccurent or high risk histological subtype)
Mohs’ micrographic surgery
* consider if lesion close to vital anatomical structure
* indistinct margins
* recurrent
Once you remove a BCC what are options for closing the site?
- close directly - if enough skin laxity in region
- local, regional free flap or skin grafts
What is Moh’s Micrographic surgery?
When is Moh’s Micrographic surgery useful? (3)
(1) recurring or incompletely removed BCC
(2) areas where it would be cosmetically better to remove as little skin as possible
(3) at sites of previous surgery or radiotherapy.
How to prevent BCC?
- Reduce their exposure to UV light and avoid sunbeds (primary prevention)
- frequent use of SPF50 sunscreen and wearing of protective clothing (secondary prevention).
prognosis for BCC?
BCCs rarely metastasis, prognosis is generally good.
Incomplete excision is more common in periorbital and nasal lesions - incompletely excised BCCs generally have a 30-40% recurrence rate.
Derm BAD book:
prognosis depends on:
- tumour size
- tumour site
- growth pattern, histolological subtype
- failure of previous treatments/recurrance
- immunosuppression
RF for incomplete excision of BCC?
- head lesions
- certain histological subtypes (morphoeic, superficial, infiltrative)
- > 2cm lesions
- > recurrent lesions.
Are pts who have had a BCC at risk of developing further skin cancer?
- 35% risk of developing another non-melanoma skin cancer in 3 years
- 50% risk in 5 years.
What is squamous cell carcinoma SCC?
what does it arise from?
malignant tumour of keratinocytes, arising from the epidermal layer of the skin.
Keratin plug in the middle of the lesion
Most SCC arise from cumulative prolonged exposure to ultraviolet (UV) radiation, primarily UVB.
How common is SCC?
second most common form of skin cancer, after basal cell carcinoma, accounting for 20% of all cutaneous malignancies
Where do SCCs tend to be found? Who are they more common in?
- typically located found on areas exposed to high doses of UV radiation, such as the head & neck, arms, and legs
- more common in men
How does exposure to UV lead to malignancy like SCC?
Exposure to UV radiation causes numerous DNA mutations in multiple somatic genes, such as the p53 tumour suppressor gene.