When Topical Treatments Are Appropriate for Skin Cancer

For many people, the word "skin cancer" immediately brings to mind surgery. And while procedures like Mohs surgery remain the most effective treatment for the majority of skin cancers, there are situations where topical creams—imiquimod and 5-fluorouracil (5-FU)—can be excellent options.

These medications aren't right for every cancer, but in carefully selected cases they offer a non-surgical, cosmetically elegant way to treat certain skin cancers and precancers.

How These Creams Work

Imiquimod

Stimulates your immune system to destroy abnormal cells.

5-Fluorouracil (5-FU)

Directly targets and destroys cancerous or precancerous cells through a chemotherapy-like action.

Both are prescription-only and require several weeks of use.

When These Treatments Are Appropriate

Topical therapy is most commonly used for:

1. Superficial Basal Cell Carcinoma (sBCC)

This is the main skin cancer type where topical treatment can be appropriate.

• Imiquimod cure rate: about 80–90% for well-selected superficial tumors
• 5-FU cure rate: approximately 70–90%

Cure rates depend heavily on:

• Tumor size
• Location
• Pathology confirming the cancer is truly superficial

2. Squamous Cell Carcinoma in Situ (Bowen's Disease)

• Imiquimod: ~70–85% cure rate
• 5-FU: ~70–90%

These rates are good—but still lower than surgical options.

3. Widespread Precancerous Damage (Actinic Keratoses)

Topical therapy is often the best treatment here, especially for people with many precancers across the face, scalp, or forearms.

4. Patients Who Can't Undergo Surgery

For patients with bleeding disorders, healing issues, or significant medical conditions, creams may be the safer choice.

Why Mohs Surgery Is Still Often Preferable

Even though topical treatments can work well, Mohs surgery remains the gold standard for most basal and squamous cell cancers. Here's why:

1. Mohs Has the Highest Cure Rate—By Far

• Mohs cure rate for BCC: ~99%
• Mohs cure rate for SCC: 97–99%

Compared to topical therapy's 70–90%, Mohs offers the most certainty that the skin cancer is truly gone.

2. Mohs Provides Instant Margin Control

With Mohs, the surgeon examines 100% of the surgical margin under a microscope during the procedure.

Topical treatment cannot confirm whether the cancer has been fully removed—there is no microscopic check.

3. Not All Skin Cancers Are Superficial

Many basal and squamous cell cancers grow deeper or have "roots" that topical creams cannot reach.

Mohs visualizes and removes these extensions.

4. Mohs Is Safer for High-Risk Areas

The nose, eyelids, lips, ears, and scalp all require precise cancer removal with tissue preservation.

Creams are not suitable for these areas.

5. Recurrence Matters

If a cancer treated with a cream recurs later, it is often more extensive and harder to treat than the original spot.

Mohs eliminates almost all of that risk upfront.

What to Expect With Topical Therapy

While non-surgical, these creams are not "gentle."

A typical treatment course lasts several weeks and causes:

• Redness
• Crusting
• Scaling
• Burning or soreness
• A "rash-like" inflammatory reaction

These changes mean the medication is working—but they can be cosmetically intense during treatment.

Follow-up appointments are essential, sometimes including a repeat biopsy to ensure the cancer cleared.

So Which Is Best—Creams or Mohs?

It depends on the diagnosis:

Topical Therapy May Be Best When:

• The cancer is small and truly superficial
• Cosmetic outcome is a top priority
• The patient wants to avoid surgery
• There are many precancers in a broad area
• The patient has medical reasons to avoid procedures

Mohs Surgery Is Best When:

• The cancer is invasive
• The cancer is on the face or other high-risk area
• It's a recurrent tumor
• It's an aggressive subtype
• The patient wants the highest cure rate

The Bottom Line

Topical treatments like imiquimod and 5-fluorouracil are valuable tools in dermatology, offering non-surgical treatment for certain superficial skin cancers with cure rates typically in the 70–90% range.

But for most basal and squamous cell cancers—especially those on the face or with deeper growth—Mohs surgery remains the most reliable option, with cure rates close to 99%.

Choosing the right treatment requires:

• A correct diagnosis
• An understanding of cancer type and depth
• A discussion with a dermatologist or Mohs surgeon

With the right guidance, both approaches can be used effectively and safely.