Comparative study of cryopen and liquid nitrogen in actinic keratosis

  • Research type

    Research Study

  • Full title

    Comparative study on cryosurgery using cryopen and liquid nitrogen spray in the treatment of actinic keratosis (premalignant skin cancer) in out-patient dermatology clinics.



  • Contact name

    Anthony Chu

  • Contact email

  • Sponsor organisation

    Research Governance Manager Imperial College London and Imperial College Healthcare NHS Trust

  • Research summary

    Cryosurgery is broadly defined as the controlled destruction of unwanted tissue by the precise application of extreme cold during clinical procedures. It is a well proved method in effect a destruction of living tissue, because normal and diseased cellular elements will not survive after being subjected to freezing to minus (-) 27°C. In other words, how to accurately and effectively bring down the temperature without collateral damage. Common lesions treated are viral warts, skin tags, keloids and actinic keratosis (premalignant skin lesions); the latter which will be studied by us.
    The most commonly seen direct cryosurgical method is spraying liquid nitrogen directly onto the skin lesion. However, the sprayer creates divergent jets, covering the skin lesion but also the surrounding tissue. This collateral damage not only cause pain, but also limits its application to large lesion (size must be bigger than 5mm).It is necessary to store and transport it in special flasks for safety measures.
    New developments in cryosurgery with the CryoPen brings control over temperatures and penetration depth. The CryoPen offers pin- point precision and a consistent freeze temperature.CryoPen is a direct cryosurgical tool, utilising pressurised liquid nitrous dioxide (N2O, also known as laugh gas).It can bring the spot to a temperature as low as -89°C.
    The aim of our study is to evaluate the adverse side effects and collateral damages of the cryopen and liquid nitrogen in the treatment of actinic keratosis such as pain,redness & swelling,blistering,infection, scarring, discoloration changes and numbness.
    Secondary outcome is to access time of healing and clearance.

  • REC name

    Yorkshire & The Humber - Leeds East Research Ethics Committee

  • REC reference


  • Date of REC Opinion

    21 Aug 2014

  • REC opinion

    Favourable Opinion