What Is Basal Cell Carcinoma?
Basal cell carcinoma (BCC) is the most common form of skin cancer, arising from the basal cells of the epidermis. It is sometimes called a "rodent ulcer" because of its tendency to slowly erode the skin if left untreated. BCC very rarely spreads to other parts of the body (metastasis is exceptionally uncommon), but it is locally invasive — left untreated, it continues to grow and can damage surrounding skin, cartilage or bone, particularly on the face.
Causes & Risk Factors
- Cumulative lifetime exposure to ultraviolet (UV) radiation — the single most important risk factor
- Fair skin, light eyes and hair, and skin that burns easily
- Older age — though BCC can occur in younger adults
- A previous BCC, or a family history of skin cancer
- Immunosuppression, including after organ transplantation
- Previous radiotherapy to the affected area
Signs to Look For
BCC most often appears on sun-exposed skin — the face, ears, scalp, shoulders and back — though it can occur anywhere. Common appearances include:
- A pearly or translucent nodule, often with visible small blood vessels (telangiectasia) across its surface
- A sore or ulcer that does not heal, or repeatedly scabs and bleeds
- A shiny, skin-coloured or pink bump with a rolled, raised edge
- A flat, scaly, reddish patch, particularly on the trunk (superficial BCC)
- A firm, waxy, scar-like area, sometimes with poorly defined edges (a less common, more infiltrative pattern)
Diagnosis & Referral
Diagnosis begins with clinical examination, often supported by dermoscopy (magnified examination of the skin surface). A biopsy is usually taken to confirm the diagnosis and identify the specific subtype, which helps guide treatment planning — some subtypes (such as morphoeic/infiltrative BCC) grow in a less predictable pattern beneath the visible surface and may need a different surgical approach.
Referral pathways follow NICE guideline NG12 for suspected skin cancer. Most suspected BCCs are referred on a routine (rather than urgent 2-week-wait) pathway, reflecting the low risk of metastasis, though assessment should still not be delayed, particularly for lesions on the face or that are growing.
Treatment Options
- Surgical excision — the gold-standard treatment for most BCCs, removing the lesion with a margin of surrounding healthy skin (typically 4mm for well-defined, low-risk lesions; wider margins for high-risk or infiltrative subtypes), with the wound closed directly or reconstructed depending on size and site
- Mohs micrographic surgery — a specialist technique examining the entire excision margin under the microscope during the procedure itself, used for high-risk, recurrent, or cosmetically or functionally sensitive sites (such as around the eyes, nose or ears), maximising tissue preservation while confirming complete removal
- Topical treatment (imiquimod or 5-fluorouracil) — an option for selected, thin, superficial BCCs, generally with a lower cure rate than surgery
- Curettage and cautery — for selected low-risk, superficial lesions
- Radiotherapy — considered where surgery is not suitable, for example due to other health factors
Prognosis
The prognosis for BCC is excellent. Cure rates following standard surgical excision exceed 95%, and even higher with Mohs surgery for appropriate cases. Because BCC reflects an individual's cumulative sun exposure and skin type, new BCCs can develop elsewhere over time, so ongoing skin awareness and follow-up are worthwhile even after successful treatment.
Related Pages
- Skin Cancer Excision & Reconstruction
- Squamous Cell Carcinoma (SCC)
- Mole, Cyst & Lipoma Removal
- Scar Management