SCC

Malignancy of epidermal keratinocytes

Aetiology

Risk factors

UV exposure – UVB is thought to be responsible via a direct mutagenic effect on dividing keratinocytes in the basilar layer of the epidermis depression of cutaneous immune surveillence

XRT

Smoking

— Oral

Viral infection

— HPV infection

— EBV infection

Organic hydrocarbons

Ingestion of arsenicals

Immunosuppression – the intensity and duration of immunosuppression is associated with disease.       Immunosuppressive drugs, leukemia, lymphoma and auto-immune disease. HPV is causative             factor in genital acral and peri-ungual regions

Chronic ulceration

Actinic keratosis

Bowen’s

Xeroderma pigmentosa

— RR 1000x

— Autosomal recessive

— susceptibility to sunlight induced damage

— inability to repair DNA damage

Albanism – partial or complete deficiency of melanin production

Pathology

Macro

Area of keratosis with small oozing ulcer

Widely ulcerated with raised indurated everted edges

Occasionally inflammatory appearance

— Tend to be poorly diff.

Micro

Tongues of squamous cells invading BM of dermis

Pale nucleus, eosinophilic cytoplasm

Intercellular bridges

Keratin pearls of central keratin surrounded by prickle cells

Variants

Spindle cell

            — Poorly diff

Pseudoglandular

            — Acantholysis pseudoacinar pattern

            — Can be mistaken for adenoCa

Verrocous

            — Slow growing

            — Mouth, larynx, genitalia and occasionally skin

            — Fungating

            — Invade deeply and extensively

            — Rarely metastasis

            — Can progress to high grade SCC after XRT

Staging

TNM

T

T1      2cm

T2        2-5cm

T3        >5 or deep dermal invasion

T4        Invasion of other extra-dermal structures (skeletal muscle, bone, tendon)

            N

N1 movable ipsilateral

N2 movable contralateral or bilateral

N3 fixed regional

Spread

Rate of lymph node metastasis depends on site of origin

Sundamaged skin 3%

Mucocutaneous 11%

Clinical

Middle age – elderly

— 40-80yrs

Exposed skin

— Nose

— Ear lips forehead

Relatively more common on non-exposed skin than BCC

Rx

Treatment of primary site

A skin biopsy is important before treatment of any skin cancer.

Most non-melanoma skin cancers are small low risk lesions that respond with a 90-95% success rate to standard treatment.

Excision

— with margins clear of carcinoma typically 5-10mm of normal appearing skin for low risk SCC (the evidence regarding the adequacy of margins is less clear than melanoma).

Radiotherapy

Can be used for 1° treatment

Avoid pinna (radionecrosis) and scalp (hair loss)

Cosmetic results good to excellent especially for preserving large areas of skin in head and          neck region.

            — small amount of hypopigmentation or telangiectasia in the treatment

Indications

— Recurrence after surgery where re-excision is not possible

— H&N

Contraindications:

— xeroderma pigmentosum,

— epidermodysplasia verruciformis

— basal cell nevus syndrome: may induce more tumors in Rx area

Adjuvant XRT to primary site and draining lymph nodes may also be used when many high risk factors (see Mohs) are present, or there is extensive neurotrophism

Mohs micrographic excision

—    Mohs may reduce recurrence rate when there are risk factors for subclinical invasion and recurrence.

o   Recurrent tumour

o   Tumour is on the hand/foot, genitals, in front or behind ear, temple, mandible or chin, lip, nose, peri-orbital region or central face and >6mm

o   Cheek, forehead, scalp or neck and >10mm

o   Trunk or extremity and >20mm

o   Poorly differentiated

o   Clark level V or >4mm deep

o   Perineural invasion

o   Rapid growth

o   Associated with scars or prior radiotherapy

o   immunosuppression

Field therapy techniques

Cryotherapy

Can be used for well defined in situ lesions

Absolute C/I

— abnormal cold tolerance

— cryoglobulinemia

— cryofibrinogenemia

— Raynaud's disease

only for treatment of lesions on hands and feet

— platelet deficiency disorders

— Morphea (localized cutaneous scleroderma)

— sclerosing basal cell carcinoma

Relative C/I

            tumors of scalp

            ala nasi, nasolabial fold, upper lip vermillion border

            tragus, postauricular sulcus

            free eyelid margin

            lower legs

Morbidity

— Oedema

especially around the periorbital region, temple, and forehead

— Treated tumors usually exude necrotic material, after which an eschar forms and persists

for about 4 weeks

— Permanent pigment loss at the treatment site is unavoidable

— Atrophy and hypertrophic scarring have been reported, as well as instances of motor and

sensory neuropathy.

Topical 5FU

Can be used for Rx of in-situ lesions and small superficial lesions

N+

Excision and block dissection

Prognosis

Variable behavior

SCC in burns and irradiated skin aggressive and frequently metastasise

Recurrence

Usually appear within 6/12

Depends on grade and depth

— Low grade 7%

— Moderate 23%

— High 28%