What is true of intradermal Squamous Cell Carcinoma (SCC): will it progress to invasive, can it be left and monitored, or should 5-Fluorouracil (5-FU) be applied?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: April 28, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

Intradermal squamous cell carcinoma (SCC) will progress to invasive disease in a small percentage of cases, and therefore, should not be left and monitored, but rather treated with options such as topical 5-fluorouracil (5-FU) cream. The use of 5-FU cream is a well-established treatment option for SCC in situ, as supported by the British Association of Dermatologists' guidelines 1. According to these guidelines, topical 5-FU is a recognized treatment option, with a typical regimen of once- or twice-daily application for 3–4 weeks, repeated if required.

Some key points to consider when treating intradermal SCC include:

  • The potential for progression to invasive disease, although rare, necessitates treatment rather than observation
  • Topical 5-FU cream is an effective treatment option, with response rates comparable to other treatments such as photodynamic therapy (PDT) and cryotherapy 1
  • The choice of treatment depends on factors such as lesion size, location, patient preference, and comorbidities
  • Regular follow-up is necessary after treatment to monitor for recurrence or development of new lesions

In terms of treatment specifics, topical 5-FU cream, applied once daily for 1 week, then twice daily for 3 weeks, has been shown to be effective in treating intradermal SCC, with complete response rates of 83% at 3 months following the last treatment 1. However, it is essential to consider the potential for recurrence and the need for repeated treatment or alternative therapies.

From the Research

Characteristics of Intradermal SCC

  • Intradermal SCC, also known as squamous cell carcinoma in situ, is an intra-epidermal malignancy with the potential to progress to invasive carcinoma 2, 3.
  • It is considered a precursor to squamous cell carcinoma and should be treated before invasive cancer develops, especially in high-risk individuals such as transplant recipients 3, 4.

Treatment Options

  • Various treatment modalities are available, including surgical excision, cryotherapy, photodynamic therapy, laser ablation, curettage with cautery, radiotherapy, topical 5-fluorouracil, and topical imiquimod 2, 3, 5.
  • Topical 5-fluorouracil has been shown to be effective as both primary therapy for SCC in situ and as adjuvant therapy for residual SCC in situ following Mohs micrographic surgery for invasive SCC 6.
  • Surgical excision is considered the gold standard treatment for squamous cell carcinoma in situ, although less invasive methods may sometimes be preferred 2, 4.

Progression and Monitoring

  • There is a potential for intradermal SCC to progress to invasive carcinoma, highlighting the importance of timely and effective treatment 2, 3.
  • The decision to monitor or treat should be based on individual patient factors and the specific characteristics of the lesion, with treatment options selected accordingly 3, 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Treatment of squamous cell carcinoma in situ: a review.

Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.], 2011

Research

Squamous Cell Carcinoma: An Update on Diagnosis and Treatment.

Dermatology practical & conceptual, 2020

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.