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Atlas of visual inspection of the cervix with acetic acid for screening, triage, and assessment for treatment

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Treatment by cryotherapy – Steps

  

  • Counsel the woman and obtain informed consent.
  • Re-evaluate the lesion (either by performing colposcopy or with naked eye after application of 3-5% acetic acid or with a magnifying device after application of 3-5% acetic acid) and ensure that:
    • The squamocolumnar junction (SCJ) is fully visible and is on the ectocervix or at the external os.
    • If there is a visible lesion, it is on the ectocervix without any extension to the endocervix or to the vagina.
    • If there is a visible lesion, it does not occupy more than 75% of the ectocervix.
    • The transformation zone or the lesion (if present) can be fully covered by the tip of the largest cryotherapy probe.
    • There is no suspicion of invasive cancer (either on naked eye or on colposcopy or on earlier cytology or histopathology reports).
    • There is no suspicion of adenocarcinoma in situ (e.g. a cytology report suggesting abnormal glandular cells).





  • No anaesthesia is required.
  • If required, obtain a punch biopsy from the cervix. Stop the bleeding with Monsel’s paste or silver nitrate or pressure before proceeding to the next steps.
  • Select a probe with a tip of appropriate diameter that will cover the transformation zone/ lesion completely. Attach the probe to the handle grip (cryogun).
  • Connect the valve with the pressure gauge to the gas cylinder. The pressure of the gas cylinder should be 40–70 kg/cm2 when the gas is flowing (indicator in the green zone).
  • Wipe the cryotip with saline to ensure adequate thermal contact.
  • Apply the probe tip firmly to the cervix with the centre of the tip on the external os.
  • Check that the vaginal walls are not touching the probe tip.
  • Press the trigger on the handgrip so that gas starts flowing; start the timer.
  • Check for the formation of ice at the tip of the probe.




  • Release the trigger after 3 minutes, when you will see an ice ball formed over the cervix extending 4–5 mm beyond the edge of the tip.
  • If the ice ball has formed adequately, the probe tip will remain stuck to the cervix.




  • Wait for 5 minutes for thawing, when the ice will melt and the probe may detach from the cervix.
  • Reapply the probe at the same place as before and freeze the cervix for another 3 minutes.
  • Always follow the double freeze method of 3-5-3 cycle (3 minutes of freezing, 5 minutes of thawing and 3 minutes of freezing.
  • Release the trigger and wait until the ice melts and the probe detaches from the cervix on its own.
  • The cervix will have a white crater, which indicates that the cervix is properly frozen.




  • Remove the speculum gently.
  • Ask the woman to continue lying down for 5 minutes before letting her get up.
  • Counsel the woman and give appropriate follow-up advice.




For additional information, please refer to WHO technical specifications: cryosurgical equipment for the treatment of precancerous cervical lesions and prevention of cervical cancer.

























  


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