Basal Cell Carcimoma - Superficial

Synonyms: erythmatoid or pagetoid basal cell carcinoma

A clinical subtype of basal cell carcinoma (BCC)

For BCCs in general:

• BCCs are the commonest malignancy affecting white people and incidence is increasing worldwide.
• Lifetime risk of developing a BCC in white american populations is approximately 30%.
• Occur in older people so aging populations will increase their incidence and prevalence.

For superficial BCCs in particular:

• An australian study showed an incidence for superficial BCCs of 336.5/100,000 men and 251.4/100,000 women per annum.² Note, study performed in area of high sun exposure compared to UK.
• Occur at a younger age than other BCC variants, particularly in women.

Risk factors include:

• Exposure to sunlight - critical amount, timing and pattern of exposure to developing a BCC unclear as long latency (usually 20-50 years)
• Celtic ancestry - skin type 1(always burns, never tans), red/blonde hair and blue/green eyes
• Recreational sun exposure in childhood and adolescence
• Family history
• Arsenic exposure - multiple BCCs
• Immunosuppressive therapy
• Certain genetic conditions eg albinism, xeroderma pigmentosa, Gorlin's syndrome.

Susceptibility to BCC appears to be due to a complex interaction between duration and intensity of ultraviolet radiation exposure and polymorphic genes. Why BCCs should have such clinical diversity is as yet unanswered by molecular science.

For image see ³

• Scaly patch
• Pink to red-brown in colour
• Central clearing
• Thread-like border
• If stretched, a rolled edge can be seen
• Usually flat.

• A small erythematous scaly plaque
• Very slow growing
• Over months to years it may grow to become several centimetres in diameter
• It may bleed or weep
• Equal distribution over face, trunks and limbs - although site of predilection seems to vary according to sex (head in women, trunk in men).⁴

• Psoriasis
• Bowen's disease
• Solar keratosis
• Eczema
• Lichen simplex.

Superficial BCCs are commonly diagnosed and treated in primary care, especially in areas of high incidence, eg Australia⁶.

• Biopsy if diagnosis is in doubt.

Treatment options include:

• Surgical:
  • Cryotherapy
  • Curettage and/or cautery
  • Excision.
• Non-surgical:
  • Flurouracil 5% cream - useful where multiple lesions on the trunk or limbs.
  • Imiquimod 5% cream - recently licensed treatment for small, superficial BCCs. Good clearance rates (70-100%) but relapse rates appear higher than with other, conventional treatments and some difficulties with side-effects (eg pruritus) reported.⁷
• Sometimes, in the very elderly and debilitated, treatment may be declined in favour of no treatment (given the slow growth and low risk of many superficial BCCs) or palliative (debulking or radiotherapy) therapy where the tumour is symptomatic.

For help with diagnosis and treatment (difficult body sites, large lesions or recurrence).

Additional treatment options in secondary care include:

• Photodynamic treatment
• Radiotherapy
• Mohs surgery.

• Usually not an aggressive form of BCC - rare to become invasive and extremely rare to metastasise. Compared to nodular BCCs, less likely to erode and ulcerate. Tumour type is one element in the identification of high and low risk BCCs (the others being size, site, growth pattern, histology type, failure of previous treatment and immunocompromised patient).
• Recurrent tumours have poorer cure rates compared to the treatment of primary tumours.
• Having had a BCC, increased risk of developing further lesions, particularly in those presenting with truncal lesions (hazard ratio 1.58).
• Increased risk of malignant melanoma - presumably as sun exposure is important in the causation of both.

Avoid UV exposure in susceptible individuals, particularly children and adolescents.
Educate to:

• Stay out of the sun 10am - 4pm
• Use high factor sun screens
• Wear wide-brimmed hats, long-sleeved shirts and trousers.