Cryotherapy (Cryosurgery)

Cryotherapy (using liquid nitrogen) is the process of freezing skin lesions. The extreme cold both destroys skin tissue and stimulates the immune system. Both processes help to clear/remove the lesion.

This is a useful alternative to surgery for pre-cancerous lesions (solar/actinic keratoses and Bowen’s disease), warts and seborrhoeic keratoses.

How does it work?

The cryogen is usually liquid nitrogen, though other substances can be used. It is usually applied with a spray-gun, but sometimes a cotton tip is used.  Traditionally 3 ‘freeze-thaw’ cycles are used lasting a few seconds for each cycle. It stings when applied and can cause painful blistering within a few hours. This usually settles spontaneously and forms a scab.

Healing times are approximately 5-14 days on the face, 2-3 weeks on the trunk and up to 6 weeks on the lower legs. This is a very safe treatment but possible complications include scarring, infection or hypopigmentation (whitening) of the area treated. If the lesion recurs, it may need further treatment with cryotherapy or possibly another option such as surgery or specialised creams.

Immune modulants

Immune modulants are chemotherapeutic topical creams that stimulate the body’s own immune system to fight against the abnormal sun-damaged cells or skin cancer cells (eg. Superficial BCCs).

5 fluoro-uracil (5-FU)

Topical 5-fluorouracil 5% cream (Efudix™) is a chemotherapeutic agent prescribed by a skin cancer specialist such as Mr Banwell. It may be very effective in the management of actinic keratoses , in-situ squamous cell carcinoma (Bowen’s disease) but is also effective for superficial basal cell carcinomas [please note that it is not effective for other types of BCC]. It is also sometimes used in combination with salicylic acid in the management of persistent and symptomatic viral warts in adults.

It works best on face and scalp but can be effective on other areas too. Pre-treatment with a topical retinoid may enhance the effect of fluorouracil by peeling off the top layer of skin.

The optimal way to use fluorouracil is unknown. Most skin cancer specialists recommend daily applications for 4 weeks, which may be repeated as necessary. To reduce the severity of adverse reactions, others recommend treatment for a few days, repeated as necessary, or twice weekly applications over several months.

Fluorouracil creates a cytotoxic destructive reaction to dysplastic cells. Treated dysplastic lesions become red, scaly and tender over several days then erode or ulcerate with continued treatment. The more dysplastic the lesion, the more vigorous the response. Treatment should be discontinued at the eroding stage to allow re-epithelialisation over the next one to four weeks.


Imiquimod (Aldara™) is an immune response modifier / immune modulant which is even stronger than 5 FU. It is used to treat actinic keratoses, Bowen’s and superficial basal cell carcinomas (BCC)s. It may also be useful for treatment pigmented patches of skin. Results from early clinical trials in the USA also suggest it may have an important role in anti-ageing too!

As mentioned above with 5-FU, the degree of inflammation with Aldara is quite variable. The greater the inflammation, in general the shorter the time and number of applications required to eradicate the lesion. About 10% get little or no inflammatory response and treatment is then nearly always ineffective. On the whole, as with other topical treatments, facial lesions clear quicker than those elsewhere.

A course of treatment ranges from 4 to 16 weeks.

Actinic keratoses – 2 to 3 times weekly

Superficial basal cell carcinomas and Bowen's disease – 5 times weekly; interrupt treatment if inflammatory response is excessive

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Please contact Mr Banwell's office on 01342 330302 or email for further information.

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Skin Facts

Did you know that sun protection factors (SPFs) are both anti-skin cancer and anti-ageing too!

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