Basal cell carcinoma

Epidemiology
- Technically the most common cancer, but it is often excluded from data due to its low mortality and morbidity
- BCC accounts for 75% of all skin cancer
- Most common skin cancer
Pathology
- Hedgehog pathway is often mutated
- Almost never metastasises, leading to low mortality and morbidity
- May cause local destruction, which may be severe if located on the face
- Types
  - Nodular BCC
  - Superficial BCC
  - Morpheaform BCC
  - Naevoid basal cell carcinoma syndrome
    - Autosomal dominant disease
    - Multiple BCC in young age
    - Bone and neurological malformations
  - +++
Risk factors
- Chronic sun exposure
- Old age
- Skin types I and II
Clinical features
- Pearly papule or nodule
- Rolled border
- Central crater of ulceration
- On sun-exposed skin
  - Usually upper lip/nose area
- Slow growing
Types
- Nodular BCC
  - Most common type
- Superficial BCC
  - On trunk
  - Flat plaque lesion
- Nevoid basal cell carcinoma syndrome
Prognosis
- Virtually never metastasizes
- Locally aggressive
Diagnosis
- Clinical, based on typical symptoms
- Definite (histological) diagnoses often made after surgical excision of suspected lesion
- Full-thickness biopsy -> histology
Treatment
- Surgery
  - Surgical excision with 5 mm safety border
  - Primary treatment is almost all cases
- Radiotherapy
  - If surgery is not an option
- Chemotherapy
  - Only topical (5-FU)
- Alternatives for superficial and small BCCs
  - Cryosurgery
  - Photodynamic therapy
  - Laser ablation
  - Topical chemotherapy
  - Topical imiquimod
- Targeted therapy
  - Vismodegib or sonidegib
    - Hedgehog pathway inhibitors
  - For metastatic BCC or BCC which recurs after surgery
Follow-up
- Physical examination at 3, 6, 12 months
- Sun protection