Freezpen - Clinic 6

01. Principles of cryotherapy

Cryosurgery = better immune response

"Post-thawing, mechanically damaged cells die by necrosis and release their contents into the surrounding milieu. Cells that have undergone exosmosis swell and burst due to osmotic shock. Cells in the utmost periphery of the ablation zone exposed to sub-lethal temperatures undergo apoptosis, releasing apoptotic bodies. Antigens released from necrotic cells upon uptake by antigen presenting cells like DCs (Dendritic cells) induce co-stimulatory signals that would result in the generation of anti-tumoral T-cell responses. In contrast, antigen uptake by DCs in the form of apoptotic bodies imprints immune tolerance or anergy on T-cells due to the non-induction of co-stimulatory signals on DCs."

Yakkala, C., Chiang, C. L., Kandalaft, L., Denys, A., & Duran, R. (2019) ‘Cryoablation and Immunotherapy: An Enthralling Synergy to Confront the Tumors’, Frontiers in Immunology, 10, 2283.

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Why is double freezing so important?

• Freezing in two steps results in deeper tissue necrosis. While the first freeze causes tiny spiked chards of extracellular ice, which actually helps preserves cells, the second freeze cause these ice crystals to break through the cell membrane for complete cell destruction.

• A second freeze ensures faster freezing of these cells and their destruction.

Advantages of Freezpen’s controlled cell destruction:

01. No trauma to healthy tissue – low or no pain – no anesthesia needed

02. Less scarring or depigmentation

03. Higher gas-use efficiency – faster treatments

04. Great patient experience – painless and effective

05. The standard treatment for all HPV lesions and keratoses

02. Device preparation

Tips for using your Freezpen

Always test your Freezpen before performing treatment.

• Always check that your cartridge is empty before replacing it

• If you open your Freezpen when the cartridge still contains N2O, the remaining contents will be expelled, resulting in waste

•  Check to be sure the loading cavity is completely clear and empty before loading in a new cartridge

How to clean Freezpen applicators ?

01. Remove the applicator from the Freezpen device

02. Remove the applicator cap

03. Stand the cap and applicator upright in a sterilizing tray/basket

04. Follow the sterilizer manufacturer’s instructions to complete the sterilization process

IMPORTANT: Applicators that touch HPV lesions must be cleaned and sterilized using:


34°C/273°F for 4 minutes or 121°C/250°F for 20 minutes


121°C/250°F for 30 minutes

03. Protocol

How to treat with Freezpen

Quick tips


• Be guided by your patient’s sensitivity: before starting treatment, pre-freeze and ask the patient to indicate when they feel pain

• Wait 30 seconds between freeze sessions

• Cold penetrates 1mm deep per 3 seconds

• Applicator tip closer to the lesion = higher freezing power to the tissue

What happens during a treatment?

During treatment, patients may feel a sensation similar to a cold ballpoint being pushed onto the skin. During the first few seconds, provided healthy tissue is avoided, they will experience little or no discomfort.

As soon as the ice reaches the caudal extent of the lesion – timing depends on the depth of the lesion – the patient will start to experience discomfort. Stop the treatment at that moment.

There may be residual stinging for a few minutes after treatment. Occasionally, a blister may form and last for a few hours. The area may be itchy, and you should advise the patient to avoid scratching it.

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