What are the options for local management of basal cell carcinoma (BCC)?

Local Management Options for Basal Cell Carcinoma

For basal cell carcinoma (BCC), surgical treatment remains the cornerstone of management, with Mohs micrographic surgery being the preferred option for high-risk tumors due to its superior cure rates and tissue preservation. 1

Risk Stratification

Before selecting treatment, BCCs should be classified as low-risk or high-risk based on:

High-Risk Features:

• Location: H-zone of face (central face, eyelids, eyebrows, periorbital, nose, lips, chin, mandible, preauricular/postauricular skin/sulci, temple, ear)
• Size: >2 cm on trunk/extremities, >1 cm on cheeks/forehead/neck/scalp, >0.6 cm in high-risk areas
• Histologic subtype: Infiltrative, micronodular, sclerosing/morpheaform, basosquamous
• Perineural involvement
• Previously treated/recurrent tumors
• Immunosuppressed patients

Surgical Treatment Options

1. Mohs Micrographic Surgery (MMS)

• Indication: First-line for high-risk BCCs
• Advantages:
  • Highest cure rates (5-year recurrence rate of only 1% for primary BCC and 5.6% for recurrent BCC) 1
  • Maximum tissue preservation
  • Complete margin assessment (100% of margins examined)
• Technique: Sequential removal of tumor with immediate frozen section analysis until clear margins are achieved

2. Standard Surgical Excision

• Indication: Appropriate for low-risk primary BCCs
• Margins: 4-mm clinical margins for low-risk tumors 1
• Considerations:
  • Requires histologic margin assessment
  • 5-year recurrence rate of 10.1% for primary BCC 1
  • Deep margin should extend through subcutaneous fat for nodular/superficial BCCs, but to the first underlying anatomical plane for infiltrative BCCs 2
  • Positive margins increase recurrence risk to 26.8% vs. 5.9% with negative margins 1

3. Curettage and Electrodessication (C&E)

• Indication: Only for selected low-risk tumors in non-terminal hair-bearing locations 1
• Limitations:
  • Not recommended for:
    • High-risk locations (H-zone)
    • Terminal hair-bearing areas (scalp, pubic, axillary regions, beard area)
    • Recurrent tumors
  • No histologic margin control
  • Inferior cosmetic outcome in sensitive areas

Non-Surgical Options

1. Radiation Therapy

• Indication:
  • Primary therapy for patients who cannot undergo surgery
  • Adjuvant therapy for tumors with substantial perineural involvement
• Considerations:
  • 5-year recurrence rates of 8.7-10% 1
  • Contraindicated in genetic conditions predisposing to skin cancer and connective tissue diseases 1
  • Generally reserved for patients >60 years due to long-term sequelae 1
  • Poorer cosmetic outcomes compared to surgery

2. Topical Therapies (for superficial BCCs only)

• Imiquimod 5% cream:
  • FDA-approved for superficial BCC ≤2 cm 3
  • Application: 5 times per week for 6 weeks 3
  • Lower cure rates than surgery
  • Common side effects: local skin reactions, erythema, erosion, scabbing/crusting

3. Cryosurgery

• Indication: Selected low-risk tumors when more effective therapies are contraindicated
• Limitations:
  • No histologic margin control
  • Recurrence rates of 6.3-39% at 1-2 years 1
  • Should be avoided for high-risk tumors

4. Photodynamic Therapy (PDT)

• Indication: Alternative for superficial, low-risk BCCs
• Limitations:
  • Lower cure rates than surgery
  • Not recommended for nodular or infiltrative subtypes

Management of Special Situations

Incompletely Excised BCCs

• Re-treatment is strongly recommended, especially for:
  • Tumors in critical midfacial sites
  • Deep margin involvement (33% recurrence risk vs. 17% for lateral margins) 1
  • Aggressive histological subtypes
  • Repairs using flaps or grafts
• MMS or re-excision with frozen section control is preferred 1

Advanced or Metastatic BCC

• Vismodegib: FDA-approved for metastatic BCC or locally advanced BCC that has recurred after surgery or for patients who are not candidates for surgery and radiation 4
• Dose: 150 mg orally once daily 4
• Caution: Severe embryo-fetal toxicity risk

Treatment Selection Algorithm

1. Determine risk status (low vs. high-risk based on location, size, histology)
2. For low-risk primary BCCs:
   • Standard excision with 4-mm margins OR
   • C&E for small, superficial tumors in non-hair-bearing, non-cosmetically sensitive areas
   • Consider topical therapy or PDT for superficial subtypes if surgery contraindicated
3. For high-risk BCCs:
   • Mohs micrographic surgery (preferred)
   • If MMS unavailable, consider standard excision with wider margins and careful histologic assessment
4. For patients unable to undergo surgery:
   • Radiation therapy (if >60 years old)
   • Vismodegib for locally advanced or metastatic disease

Pitfalls to Avoid

• Underestimating the extent of infiltrative or micronodular BCCs (require deeper excision)
• Using non-surgical approaches for high-risk tumors
• Inadequate follow-up (56% of recurrences occur beyond 5 years after treatment) 1
• Neglecting to re-treat incompletely excised tumors, especially with deep margin involvement
• Using C&E in terminal hair-bearing locations where follicular extension may occur