[5] Squamous Cell Carcinoma Flashcards
What is squamous cell carcinoma?
A malignant tumour that arises from the keratinising cells of the epidermis or its appendages
How does squamous cell carcinoma spread?
It is locally invasive, and has the potential to metastasise to other organs in the body
What are the risk factors for squamous cell carcinoma?
- Chronic UVR exposure
- Susceptibility to UV light exposure
- Chemical carcinogens
- HPV infection
- Ionising radiation
- Immunodeficiency
- Chronic inflammation
- Genetic conditions
- Pre-malignant conditions
What is the result of chronic UVR exposure increasing the risk of squamous cell carcinoma?
High rates in countries like Australia
Other than living in hot countries, what can cause increased UVR exposure?
- Frequent holidays in the sun
- Outdoor occupations
- Leisure pursuits
- Use of tanning beds
Give 2 examples of things that indicate a susceptibility to UV light exposure
- Fair skin
- Blonde/red hair
Give 3 examples of chronic inflammation that can increase risk of SCC
- Chronic ulcers
- Osteomyelitis
- Lupus vulgaris
Give 2 examples of genetic conditions that increase risk of SCC
- Xeroderma pigmentosum
- Albinism
Give an example of a pre-malignant condition that increases the risk of SCC
Bowen’s disease
How might SCC present?
- Indurated nodular keratinising or crusted tumour, that may ulcerate
- Ulcer without evidence of keratinisation
- Reddish skin plaque
Is the clinical appearance of SCC variable?
Yes, very
What are the differentials for SCC?
- Keratocanthoma
- BCC
- Malignant melanoma
- Solar keratosis
- Pyogenic granuloma
- Seborrhoeic warts
- Plantar warts or verrucas
What are the primary investigations for SCC?
- Visual inspection
- Removal for histology where necessary
What types of biopsy may be used in SCC?
- Excisional biopsy
- Incisional or punch biopsy
What happens in an excision biopsy?
The whole lesion is excised
When is an excision biopsy used in SCC?
Small lesions that are accessible and not in cosmetically sensitive areas, or near to vital structures
Under what anaesthesia are excision biopsy for SCC carried out?
Local anaesthesia for most lesions
How much should be taken in excision biopsy for SCC?
- Full thickness of skin
- Wide margins
Why should the full thickness of the skin be taken in SCC?
Determine depth of spread
Why should the excision be well wide of margins in SCC?
To achieve clearance
What happens in incisional or punch biopsy?
Part of the lesion is excised
When is incisional or punch biopsy used in SCC?
When the lesion is large, in cosmetically sensitive areas, or close to vital structures
What may investigations be required for in advanced SCC?
To assess the extent of disease
What investigations may be done to assess extent of disease in advanced SCC?
- CT or MRI scanning
- Histological examination of clinically enlarged nodes
How can histological examination of clinically enlarged nodes be carried out?
Fine needle aspiration or excisional biopsy
When should you consider a 2WW for SCC?
For people with a skin lesion that raises suspicion of squamous cell carcinoma
What is Tis in SCC?
Carcinoma in situ
What is T1 in SCC?
Tumour 2cm or less
What is T2 in SCC?
Tumour >2cm but <5cm
What is T3 in SCC?
Tumour >5cm
What is T4 in SCC?
Tumour invading deeper extra dermal structures
What is N1 in SCC?
Regional lymph node spread
How is SCC staged?
0 - IV
What is stage 0 in SCC?
Tis, N0, M0
What is stage I in SCC?
T1, N0, M0
What is stage II in SCC?
T2/T3, N0, M0
What is stage III in SCC?
T4, N0, M0, or any T, N1, M0
What is stage IV in SCC?
Any T, any N, M1
What are the management options for SCC and its precursors?
- Complete surgical excision
- Curettage and cautery/electrodessication
- Cryotherapy/cryosurgery
- Topical treatment
- Photodynamic therapy
- Electrochemotherapy
- Radiotherapy
What is the standard effective treatment for SCC?
Complete surgical excision
What should be done with all excised specimens in SCC?
Sent for histopathological examination
What happens in curettage and cautery/electrodessication for SCC?
A curettage is used to remove soft tissue from the tumour. The base of the tumour is then destroyed, either by hyfrecation or cautery
When can curettage and cautery/electrodessication be used to treat SCC?
Small (less than 1cm) in situ SCCs and pre-cancerous lesions
What are the advantages of curettage and cautery/electrodessication for SCC?
- Safe and well tolerated
- Provides good cosmetic outcomes
- Suitable for patients with multiple lesions
What are the disadvantages of curettage and cautery/electrodessication for SCC?
Histology may be difficult to interpret, and the margins of excision cannot be assessed optimally
What is cryotherapy/cryosurgery used for in SCC?
Small in situ SCCs and pre-cancerous lesions
What is the advantage of cryotherapy/cryosurgery for SCC?
Cost effective
What is the disadvantage of cryotherapy/cryosurgery for SCC?
Histology not available unless incisional biopsy is taken
What is topical treatment used for in SCC?
Pre-malignant lesions
What topical treatments can be used for pre-malignant lesions?
- Imiquimod 5% cream
- Flurouracil
What is imiquimod 5% cream used for in pre-malignant lesions?
Treat actinic keratosis
What is fluorouracil used for in SCC?
Superficial malignant and pre-cancerous lesions
What happens in electrochemotherapy for SCC?
Chemotherapy drugs are given, either IV or directly into tumour, then shortly after drug administration brief and intense electric pulses are delivered around or directly into the tumour, using either surface plates or needle electrodes
What is the limitation of electrochemotherapy for SCC?
Evidence of it’s efficacy is limited
When is radiotherapy a useful treatment in SCC?
- In patients who are unable or unwilling to undergo surgery
- Advanced, inoperable disease
- Palliation
What are the cure rates for skin lesions in SCC?
Over 90% for most skin lesions
What is the limitation of radiotherapy for SCC?
- Long term cosmetic outcome is inferior to surgery
- Same area cannot be treated twice
What is the result of radiotherapy not being able to be used twice in the same area for SCC?
If there is recurrence, surgery is used, and surgery may be more difficult than if the lesion had been removed surgically to start with
What is the role of radiotherapy in advanced, inoperable SCC?
Can be curative
When does radiotherapy have a role in palliation in SCC?
- Large, inoperable, or recurrent SCC
- Inoperable mets in lymph nodes
What factors affect the metastatic potential of SCC?
- Site
- Diameter
- Depth
- Poor histological differentiation
- Host immunosuppression
- Locally recurrent ideas
Order sites of SCC from most to least likely to metastasise?
- Sun-exposed areas
- Lip
- Ear
- Non-sun exposed sites
- Areas of radiation or thermal injury
How does diameter affect the risk of metastasis of SCC?
Tumours greater than 2cm in diameter are twice as likely to reoccur locally, and 3 times as likely to metastasise
How does the depth affect the risk of metastasis of SCC?
Tumours greater than 4mm in depth, or extending down into subcutaneous tissue are more likely to recur and metastasise than thinner tumours
What is the overall mortality rate of SCC?
<5%
What is the 5 year survival rate of SCC when distant metastases are present?
25-40%
