What are the next steps for a patient with nodular and infiltrative basal cell carcinoma (BCC) of the left forearm?

Management of Nodular and Infiltrative Basal Cell Carcinoma of the Left Forearm

Mohs micrographic surgery is the recommended first-line treatment for nodular and infiltrative basal cell carcinoma of the left forearm due to its superior cure rates (99% for primary lesions) and tissue preservation. 1

Treatment Algorithm for Nodular and Infiltrative BCC

First-Line Treatment:

• Mohs Micrographic Surgery
  • Gold standard for high-risk BCCs, including infiltrative subtypes
  • Offers highest cure rates (99% for primary, 94.4% for recurrent)
  • Maximizes tissue preservation
  • Particularly important for infiltrative subtype which has more aggressive behavior 1

Alternative Options (if Mohs is unavailable):

1. Standard Surgical Excision

   • Requires 5-10mm margins for high-risk/infiltrative BCCs
   • Consider delaying wound closure until pathology confirms clear margins
   • Should include deep margin to subcutaneous fat 1

2. Radiation Therapy

   • Consider only if surgery is contraindicated
   • 5-year recurrence rates of 8.7-10%
   • Generally reserved for patients over 60 years due to long-term sequelae 1

Why Topical Therapies Are Not Appropriate

Topical therapies such as 5-fluorouracil and imiquimod are not recommended for nodular and infiltrative BCC of the forearm because:

• FDA approval for 5-fluorouracil is limited to superficial BCCs only 2
• Imiquimod is indicated only for superficial BCC, not nodular or infiltrative subtypes 3
• Nodular and especially infiltrative BCCs require more aggressive management due to their growth patterns and higher risk of recurrence 1

Post-Treatment Follow-Up

• Clinical follow-up every 3-6 months for the first 2 years
• Annual follow-up for at least 5 years thereafter
• Patient education on sun protection, self-examination, and warning signs of recurrence 1

Important Considerations

Risk Factors for Recurrence

• Infiltrative histological subtype is considered high-risk
• Location on extremities has better prognosis than facial lesions, but infiltrative pattern increases risk
• Incomplete excision significantly increases recurrence risk (28% of incompletely excised BCCs show tumor persistence) 4

Treatment Pitfalls to Avoid

1. Avoid curettage and electrodesiccation for infiltrative BCCs as this is contraindicated for high-risk subtypes 1
2. Do not use topical therapies as primary treatment for nodular or infiltrative BCCs as they have lower cure rates and are not indicated for these subtypes 1, 2, 3
3. Do not delay definitive treatment as infiltrative BCCs can become more difficult to treat over time

The infiltrative component of this BCC makes it particularly important to choose a treatment modality with the highest cure rate, as infiltrative BCCs are more likely to have subclinical extension beyond visible margins and higher recurrence rates compared to purely nodular BCCs 1, 5.