Topical Medications

Topical medications are medications that are applied to the skin. Topical medications for skin cancer and precancer come in the form of creams, gels, and liquid solutions.

Four topical medications are used to treat skin cancer and precancer:^1-8

• Fluorouracil (brand names: Carac, Efudex, Fluoroplex, Tolak)
• Imiquimod (brand names: Aldara, Zyclara)
• Diclofenac (brand name: Solaraze)
• Ingenol mebutate (brand name: Picato)

The recommended dosing frequency and treatment duration differ for each topical medication.

What lesions can be treated with topical medications?

Actinic keratosis. All four topical medications can be used to treat actinic keratosis. Actinic keratosis is a type of precancer, an abnormal patch of skin growth that can lead to cancer. While not all actinic keratosis growths will become skin cancer, up to 10% of actinic keratoses will become squamous cell carcinoma (SCC).⁹ Moreover, about sixty percent of SCC arise from actinic keratosis.⁹ For this reason, national cancer guidelines recommend treating actinic keratosis before they progress.¹⁰

Basal cell carcinoma. Fluorouracil (5% concentration) and imiquimod (5% concentration) are treatment options for thin (or superficial) basal cell carcinoma (BCC).^1,6 Topical medications are not as effective as surgery or radiation for BCC. Therefore, they are typically only used for low-risk BCC when more effective therapies are not possible.¹¹

Fluorouracil

Fluorouracil is a chemotherapy drug.⁶ Cancer develops when cell division becomes uncontrolled. Fluorouracil works by interfering with cell division, causing the cells to die.

When fluorouracil is applied to the skin, it kills tumor cells on the skin surface.⁶ It does not reach cells in deeper layers of skin or inside the body. This means that fluorouracil works best on abnormal cells at the skin surface. It also means that side effects are mostly limited to the treatment area. Few side effects occur elsewhere in the body.

Other names for fluorouracil are 5-fluorouracil or 5-FU. Fluorouracil is also called by the brand names Efudex, Fluoroplex, Carac, or Tolak.^1-4 The branded products vary in concentration from 0.5% (Carac) to 5% (Efudex cream).^1,3 Some products are available in generic form.

Imiquimod

Imiquimod is in a class of drugs called immune response modifiers.³ This means that imiquimod activates your own immune system.⁴ However, it is not known exactly how imiquimod treats actinic keratosis or BCC.^1-3

Imiquimod is also called by the brand names Zyclara or Aldara. It comes in concentrations of 2.5% and 3.75% (Zyclara) or 5% (Aldara).^1,2 Imiquimod is also used to treat genital and perianal warts.

Diclofenac

Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) that can be used in the treatment of actinic keratosis. It is not known exactly how diclofenac gel treats actinic keratosis.¹

Diclofenac gel is also called by the brand name Solaraze. Other topical diclofenac products (brand names: Pennsaid, Voltaren) treat arthritis pain.² In pill form, diclofenac is a pain reliever.

Ingenol Mebutate

Ingenol mebutate causes the abnormal cells in an actinic keratosis lesion to die.^1,2 It also seems to activate your own immune system. This causes immune cells called neutrophils to infiltrate (enter) the lesion.² They fight any abnormal cells that have survived the initial application of the gel.

Ingenol mebutate is also called by the brand name Picato.¹ Currently, this medication does not come in generic form.

What are the pros and cons of using topical medications?

Treating skin lesions with topical medications has several advantages:

• Little to no scarring.
• After the treated area has healed, most people are happy with the appearance.
• Treatment option when surgery would be difficult to perform.

Disadvantages of topical medications include:

• Irritation at the treatment site during and for a few weeks after treatment.
• Not effective for everyone.
• Treatment duration can be weeks or months.
• Inconvenience of daily medication application.
• Need to avoid direct sunlight during the treatment period.

All the topical medications can cause skin irritation. Skin reactions in affected areas are worse with some topical medications compared to others. Your healthcare provider should show you which areas of your skin to treat and how to apply the medication. Discuss your concerns and preferences with your healthcare provider. Together, you can select a treatment that works best for you. Follow your provider’s instructions for frequency and duration of use, and do not discontinue use without discussing with your healthcare provider first.

Before starting a topical treatment option, patients should tell their doctor about all medications (prescription and over-the-counter), herbal supplements, and vitamins they are taking.