4 - Derm - Non-melanoma skin cancers + Benign skin tumours - SCC

Question 1

% of skin cancers? what do they arise from?

Answer 1

20% of skin cancers

de novo, or from AK/Intra epidermal ca

Question 2

SCC may be ass w?

Answer 2

mainly UV exposure

maybe long term imm supp and HPV infection

Question 3

7 features that mean it is at greater risk of mets

Answer 3

on ear/lip (SMx)
>2cm diameter
thicker depth
site of low sun exposure/chronic inflammation
poor differentiation
immsupp
mucosal
perineural invasion

Question 4

5 - y survival? if mets? risk of secondary primary SCC?

Answer 4

75-90%, 25% if mets

30% risk of 2ndary primary SCC

Question 5

clinical features - texture? colour? growth rate? Sx?

Answer 5

firm ill defined skin coloured nodule
faster growing than BCC
surface amy be smooth, central keratosis (crusted), erosion, or non-healing ulcer
maybe painful, bleeding, oozing

Question 6

mgmt of SCC - 4 principles

Answer 6

surgical excision
radiotherapy
imiquimod/5-FU cream
curretage and cautery

Question 7

when would mohs micrographic surgery be warranted

Answer 7

high risk…

• face,lips,ears
• poorly differentiated
• poorly defined
• prev incomplete treatment
• recurrent tumour

Question 8

simple excision margins

Answer 8

if <2cm, leave 4mm margins - otherwise larger - up to 1cm

Question 9

when would imiquimod/5-FU cream be indicated

and curretage and cautery?

Answer 9

imi- if small and superficial

cur + caut - in small, low risk lesions only

Question 10

risk of radiotherapy?

Answer 10

radionecrosis, future SCC