Squamous Cell Carcinoma

Question 1

Define squamous cell carcinoma

Answer 1

Malignancy of the epidermal keratinocytes arising from proliferation of atypical keratinocytes in the epidermis, with local invasion and high chance of metastasis

Question 2

Lesions related to squamous cell carcinoma

Answer 2

Actinic keratosis: precursor lesion of keratotic hypertrophy (scales and horns)
SCC in situ (Bowen’s disease): confined to the outer layers of the skin (intact BM), flesh-coloured plaques
Marjolin Ulcer: Aggressive, ulcerating SCC that arises in chronic wounds, burns, scars or ulcers with a high rate of metastasis (40%)

Question 3

Risk factors for squamous cell carcinoma

Answer 3

UV light/sun exposure
Family history
Lighter skin
Actinic keratoses (pre-cancerous lesion)
Ionising radiation
Burns
Previous psolaren
UV-A light therapy
Arsenic and tar exposure
HPV
Long-term immunosuppression (esp. in those with renal transplants)
Xeroderma pigmentosum

Question 4

Epidemiology of squamous cell carcinoma

Answer 4

Second most common non-melanoma skin cancer worldwide
Most frequently observed in photoexposed skin
Often >40
Men have a higher incidence than women
Most common skin cancer in patients with darker skin types and in organ transplant recipients
Highest incidence of all skin cancers - Australia

Question 5

Symptoms of squamous cell carcinoma

Answer 5

Skin lesion, ulceration - non-healing
- Growing over 3-6 months (much quicker than BCC)
Recurrent bleeding
May be painful and tender
Scaly/crusty skin
Symptoms of metastases
Evidence of sun damage: Solar elastosis, cutaneous furrowing, and wrinkles

Question 6

Signs of squamous cell carcinoma

Answer 6

Skin lesion:
- Raised
- Scaly/crusty
- Hyperkeratotic
- Ulcerated
- Non-healing
- Rolled edges (like a volcano)

Question 7

Investigations for squamous cell carcinoma

Answer 7

2WW referral

1. Biopsy
2. Fine needle biopsy or lymph node biopsy
3. Staging: CT CAP, MRI, PET, FBC, LFTS, CXR

Question 8

Management for squamous cell carcinoma

Answer 8

2ww referral pathway

Before
Record the maximum lesion dimensions (diameter in mm) and immune status of the patient
Take a good quality photograph of the lesion for record, with markings made to make the site of disease clear

Options:
Pharmacological
Locally destructive - Cryotherapy, electrocautery, photodynamic therapy (using ALA or MAL)
Surgical - Margin of >4mm (low risk) or >10mm (high risk) offer to those with invasive SCC
Systemic treatment - chemotherapy
Moh’s surgery - for cosmetically sensitive areas e.g. face or tumours 2cm

+ Maintenance therapy with oral retinoids, particularly if immunosuppressed

Question 9

Complications of treatment for squamous cell carcinoma

Answer 9

Cryotherapy: Can lead to hypopigmentation long term, especially in darker skin
Electrodessication and curettage: dyspigmentation and scarring
Photodynamic: peeling, crusting, or blistering, and hyperpigmentation may occur on darkly pigmented skin
Surgery: scarring, deformities

Question 10

Prognosis of squamous cell carcinoma

Answer 10

Death from squamous cell carcinoma is rare. The main advantage from early diagnosis is less extensive treatment.
The 3-year cumulative risk of a subsequent SCC after an index SCC is 18%. This is at least a 10-fold increase in incidence compared with the incidence of first tumours in a comparable general population
- Lesions <2cm in diameter have less than half the local recurrence rate compared with lesions >2cm
Immunosuppression - more likely to develop tumours of the ear, lip, scalp, and extremities