Efudix Cream.

A Fact of life for many Australians!

5FU & treatment for solar keratosis & SCC

What is Efudix?

Efudix® cream is an effective treatment Solar Keratosis (Actinic keratosis) & Intraepithelial carcinoma (IEC/ Bowen’s). It is the most widely used cream in a skin cancer clinic.

How does Efudix work?

Sunlight damages  DNA and makes many genes in skin cells “behave” abnormally. For example, p53 is a “good” gene that suppresses abnormal growth of cells.  UVB stops this gene from working properly so that abnormal cells start to appear, manifesting as solar keratosis (sun spots).

Efudix works by blocking the production of both DNA and RNA, predominantly in the epidermal skin cells (Keratinocytes). Most new production of DNA occurs in pre-cancerous or cancerous cells and so efudix, in a sense, targets the abnormal cells. This has important practical implications. Efudix makes sunspots inflamed. However, efudix also works on the abnormal skin cells that you can’t see. When you treat a whole area of the body with efudix then red patches will appear both on the sunspots and on some areas of skin that previously appeared to look normal. This is called “field treatment” because a whole “field” of skin is being treated. This is in contrast to only  argeting visible areas with, for example, cryotherapy.

Which area should be treated?

The first thing to decide is which area of the body to treat. Efudix can be applied just to individual lesions, or to whole areas (a “field”). Field treatment is generally better when there is thought to be significant sun damaged that may not yet be visible. Let’s say there are 4 sunspots (solar keratosis) on the backs of both forearms. In this situation, it is sensible to take the opportunity to treat the whole field.

The maximum surface area that can be treated at one time is 500 cm² (23 cm x 23cm). This corresponds to the following areas:

  • A third of the diameter of both forearms (the sun-exposed areas) + the backs of the hands.
  • A wider area of both forearms (half the diameter) – without the backs of the hands.
  • or most of the face and forehead.
  • or both shins.

As you can see, it’s not possible to treat all the areas typically affected by sunspots at the same time. You might be asked to treat the face & forehead first, followed by the forearms later. Treating the face and forehead can be split up into two separate treatment periods if the area affected is greater than 500 cm² or for your comfort (treating both together might be too intense an experience).

What are the side effects of efudix?

The treated areas of sun-damaged skin become red, crusty & sore after 2 to 4 weeks. These side effects indicate that the cream is working! The list of side effects are: Itching, redness, burning sensation, severe peeling, intense swelling or inflammation, blistering, ulceration, irritation, pain, hives and rash.

Allergy to efudix can sometimes develop. An allergic reaction to efudix makes the skin inflamed in all areas that have been treated. Efudix will normally make only the sun damaged skin red –  there are “gaps” of normal looking skin in-between red inflamed areas.

It is possible (but unusual) to get scarring if the inflammation causes excessive inflammation.

How long is Efudix used for?

Generally, Efudix for solar keratosis is used twice daily for 2 weeks on the face, and twice daily for 4 weeks on the limbs. There are different schedules and your skin cancer doctor will advise you accordingly. Whilst side effects are expected, you may be asked to stop treatment if you develop symptoms such as widespread crusting, a dusky red skin colour or increased itching.

How is Efudix Cream used?

A pea-sized amount of cream is enough to cover a cheek or chin or forehead.  Four pea-sized amounts of cream covers the whole face and forehead. The maximum area treated at one time should not exceed 23 x 23cm.

Avoid contact within 1cm of eyes or mouth, and avoid use under the arms or in the groin. It’s important to minimise sunlight and use sun protection.

Wash your hands well after application. You may apply moisturizer 20 minutes after application of the efudix.

Do I need an appointment during the treatment period?

The treatment is often an intense experience. It is generally a good idea to make an appointment with the doctor 10 to 14 days after starting treatment. A steroid cream may be recommended to help settle down the side effects. It is rare that efudix treatment needs to be stopped.

It’s also also possible you may be asked to be reviewed in 6 weeks to look at any lesions that have not responded.

Efudix may be an intense experience!

How long Does Efudix last for?

This is a tricky one! Different studies give different results. A large review study found that over 60% of people required re-treatment with efudix after 1 year.¹ It has been clearly shown that sun protection reduces the development of further sunspots. So it’s really important to protect your skin, and this will help reduce the frequency of re-treatments. It is then possible to go 5 years between treatments.²

Refer to full product information & follow directions from your doctor. The areas treated and duration of treatment, in particular,  will vary from patient to patient.

1: Br J Dermatol. 2007 Dec;157 Suppl 2:21-4. Management of field change in actinic keratosis. Vatve M(1), Ortonne JP, Birch-Machin MA, Gupta G
2: How to treat solar keratosis, Dr Michael freeman, Dr Andrew Freeman,  Australian doctor 2012.
WRITTEN BY: Dr Richard Beatty