Basal Cell Cancer
Basal cell carcinoma (BCC) is a common, locally invasive, keratinocytic, or non-melanoma, skin cancer. It is also known as rodent ulcer and basalioma. Patients with BCC often develop multiple primary tumours over time.
Who gets basal cell carcinoma?
Risk factors for BCC include:
- Age and gender: BCCs are particularly prevalent in elderly males. However, they also affect females and younger adults
- Previous BCC or other form of skin cancer (squamous cell carcinoma, melanoma)
- Sun damage (photoageing, actinic keratoses)
- Repeated prior episodes of sunburn
- Fair skin, blue eyes and blond or red hair—note; BCC can also affect darker skin types
- Previous cutaneous injury, thermal burn, disease (eg cutaneous lupus, sebaceous naevus)
- Inherited syndromes: BCC is a particular problem for families with basal cell naevus syndrome (Gorlin syndrome),
What are the clinical features of basal cell carcinoma?
BCC is a locally invasive skin tumour. The main characteristics are:
- Slowly growing plaque or nodule
- Skin coloured, pink or pigmented
- Varies in size from a few millimetres to several centimetres in diameter
- Spontaneous bleeding or ulceration
BCC is very rarely a threat to life. A tiny proportion of BCCs grow rapidly, invade deeply, and/or metastasise to local lymph nodes.
Types of basal cell carcinoma
There are several distinct clinical types of BCC, and over 20 histological growth patterns of BCC.
- Most common type of facial BCC
- Shiny or pearly nodule with a smooth surface
- May have central depression or ulceration, so its edges appear rolled
- Blood vessels cross its surface
- Cystic variant is soft, with jelly-like contents
- Micronodular, microcystic and infiltrative types are potentially aggressive subtypes
Complications of basal cell carcinoma
Recurrence of BCC after initial treatment is not uncommon. Characteristics of recurrent BCC often include:
- Incomplete excision or narrow margins at primary excision
- Morphoeic, micronodular, and infiltrative subtypes
- Location on head and neck
What is the treatment for primary basal cell carcinoma?
The treatment for a BCC depends on its type, size and location, the number to be treated, patient factors, and the preference or expertise of the doctor. Most BCCs are treated surgically. Long-term follow-up is recommended to check for new lesions and recurrence; the latter may be unnecessary if histology has reported wide clear margins.
Excision means the lesion is cut out and the skin stitched up.
- Most appropriate treatment for nodular, infiltrative and morphoeic BCCs
- Should include 3 to 5 mm margin of normal skin around the tumour
- Very large lesions may require flap or skin graft to repair the defect
- Pathologist will report deep and lateral margins
- Further surgery is recommended for lesions that are incompletely excised
Mohs micrographically controlled excision
Mohs micrographically controlled surgery involves examining carefully marked excised tissue under the microscope, layer by layer, to ensure complete excision.
- Very high cure rates achieved by trained Mohs surgeons
- Used in high-risk areas of the face around eyes, lips and nose
- Suitable for ill-defined, morphoeic, infiltrative and recurrent subtypes
- Large defects are repaired by flap or skin graft
Superficial skin surgery
- Suitable for small, well-defined nodular or superficial BCCs
- Lesions are usually located on trunk or limbs
- Wound is left open to heal by secondary intention
- Moist wound dressings lead to healing within a few weeks
- Eventual scar quality variable
Cryotherapy is the treatment of a superficial skin lesion by freezing it, usually with liquid nitrogen.
- Suitable for small superficial BCCs on covered areas of trunk and limbs
- Best avoided for BCCs on head and neck, and distal to knees
- Double freeze-thaw technique
- Results in a blister that crusts over and heals within several weeks.
- Leaves permanent white mark
Photodynamic therapy (PDT) refers to a technique in which BCC is treated with a photosensitising chemical, and exposed to light several hours later.
- Topical photosensitisers include aminolevulinic acid lotion and methyl aminolevulinate cream
- Suitable for low-risk small, superficial BCCs
- Best avoided if tumour in site at high risk of recurrence
- Results in inflammatory reaction, maximal 3–4 days after procedure
- Treatment repeated 7 days after initial treatment
- Excellent cosmetic results
Imiquimod is an immune response modifier.
- Best used for superficial BCCs less than 2 cm diameter
- Applied three to five times each week, for 6–16 weeks
- Results in a variable inflammatory reaction, maximal at three weeks
- Minimal scarring is usual
5-Fluorouracil cream is a topical cytotoxic agent.
- Used to treat small superficial basal cell carcinomas
- Requires prolonged course, eg twice daily for 6–12 weeks
- Causes inflammatory reaction
- Has high recurrence rates
Radiotherapy or X-ray treatment can be used to treat primary BCCs or as adjunctive treatment if margins are incomplete.
- Mainly used if surgery is not suitable
- Best avoided in young patients and in genetic conditions predisposing to skin cancer
- Best cosmetic results achieved using multiple fractions
- Typically, patient attends once-weekly for several weeks
- Causes inflammatory reaction followed by scar
- Risk of radiodermatitis, late recurrence, and new tumours
Courtesy of Derm Net NZ
Images British Skin Foundation