Basal Cell Carcinoma: Key Facts and Management
Basal cell carcinoma (BCC) is the most common cancer in the United States, with approximately 2 million cases annually, exceeding the incidence of all other cancers combined. 1 This slow-growing, locally invasive malignant epidermal skin tumor predominantly affects Caucasians and rarely metastasizes, but can cause significant morbidity through local tissue invasion and destruction.
Epidemiology and Etiology
- BCC is showing a worldwide increase in incidence, with continued rise predicted through 2040 1
- Primary risk factors include:
- Genetic predisposition
- Ultraviolet radiation exposure (especially in childhood)
- Fair skin types I and II
- Increasing age
- Male sex
- Immunosuppression
- Arsenic exposure
- Prior radiation therapy 1
- Most BCCs develop on sun-exposed areas, particularly the head and neck region 1
- Following development of one BCC, patients are at significantly increased risk of developing subsequent BCCs at other sites 1
Clinical Presentation and Morphology
BCCs present with diverse morphological appearances:
- Nodular (most common)
- Cystic
- Superficial
- Morphoeic (sclerosing)
- Keratotic
- Pigmented variants 1
Histological subtypes include:
- Nodular
- Superficial
- Pigmented
- Morphoeic
- Micronodular
- Infiltrative
- Basosquamous variants 1
Diagnosis
- Diagnosis is primarily clinical, enhanced by good lighting and magnification
- Dermatoscopy may be helpful in some cases
- Biopsy is indicated when:
- Clinical doubt exists
- Referral for subspecialty opinion is planned
- Histological subtype may influence treatment selection and prognosis 1
- Deep reticular dermis sampling is important as infiltrative histology may be present only at deeper margins 2
Prognostic Factors
Factors associated with higher risk of recurrence include:
- Larger tumor size
- Central facial location (especially around eyes, nose, lips, and ears)
- Poorly defined clinical margins
- Aggressive histological subtypes (morphoeic, micronodular, infiltrative, basosquamous)
- Perineural or perivascular invasion
- Previous treatment failure
- Immunosuppression 1
Treatment Approaches
Treatment selection depends on risk stratification:
Low-Risk BCC
- Curettage and electrodesiccation (excluding terminal hair-bearing areas)
- Standard excision with 4-mm clinical margins
- Radiation therapy for non-surgical candidates 1
High-Risk BCC
- Mohs micrographic surgery or resection with complete margin assessment
- Standard excision with wider surgical margins
- Radiation therapy for non-surgical candidates 1
Superficial BCC
- Topical imiquimod cream is FDA-approved for biopsy-confirmed primary superficial BCC in immunocompetent adults when:
- Maximum tumor diameter is ≤2.0 cm
- Located on trunk, neck, or extremities (excluding hands and feet)
- Surgical methods are less appropriate
- Patient follow-up can be assured 3
- Application schedule: 5 times per week for 6 weeks 3
- Clinical clearance rates of 75-80% can be achieved with imiquimod 3
Important Caveats
- Metastasis is extremely rare, occurring in only 0.0028-0.55% of all BCC cases 4, but can be fatal when it occurs
- Long-standing or neglected BCCs can grow to giant proportions (>5cm) and invade underlying structures, making treatment more challenging 5
- Basosquamous carcinomas should be managed as squamous cell carcinoma rather than BCC due to their metastatic potential 2
- The efficacy and safety of treatments have not been established for immunosuppressed patients or those with Basal Cell Nevus Syndrome or Xeroderma Pigmentosum 3
- Regular follow-up is essential as patients with a history of BCC have increased risk of developing subsequent BCCs
Prevention
All patients should be educated about skin cancer prevention, including:
- Sun protection (sunscreen, protective clothing, avoiding peak sun hours)
- Regular skin self-examinations
- Routine dermatological check-ups, especially for high-risk individuals 1