Cryotherapy and Thermal Ablation of the Cervix
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Direct answer
Cryotherapy and thermal ablation destroy the abnormal transformation zone of the cervix in a single visit, and they are recommended for screen-and-treat when the lesion is eligible. Eligibility requires a fully visible lesion, a fully visible squamocolumnar junction and no suspicion of invasive cancer. Cryotherapy destroys tissue by freezing it with a cold probe, while thermal ablation destroys it with controlled heat, and neither needs excision.
What you must remember
- Eligibility: the whole lesion and the whole squamocolumnar junction must be visible, there must be no suspicion of invasive cancer, and the woman must not be pregnant.
- Screen-and-treat: visual inspection with acetic acid, with treatment at the same visit for eligible positive women, which is the model used in national cervical screening programmes in India.
- Cryotherapy: freezing by a probe, commonly a double freeze-thaw cycle (about 3 minutes freezing, 5 minutes thawing, 3 minutes freezing), with a watery discharge as the usual aftermath.
- Thermal ablation: a heated probe (formerly called cold coagulation, a misnomer) applied for a fixed time, which generally produces less watery discharge than cryotherapy and needs a power source.
- Contraindications: pregnancy, suspected invasive cancer, a lesion extending into the endocervical canal beyond view, and a squamocolumnar junction that cannot be fully seen.
- Aftercare: watery discharge for a few weeks is expected, and intercourse, tampons and douching are avoided until healing, commonly for about four weeks.
- Failure: persistent disease or a non-visible junction needs colposcopy and excision, such as loop electrosurgical excision, rather than repeat ablation.
Treating an eligible lesion, step by step
A woman with a visible, eligible lesion on the visual test is treated at the same visit, but only once the eligibility checks are complete. The steps run in order, and each one can exclude her from ablation.
- Confirm the view: Check that the lesion and the full squamocolumnar junction are visible on speculum examination before any device is used.
- Exclude cancer: Look for features that suggest invasion, such as a bleeding or friable lesion, and refer such women for biopsy and colposcopy.
- Choose the device: Use cryotherapy or thermal ablation according to available equipment, following the protocol for freezing or heating time.
- Treat and counsel: Apply the probe to cover the lesion, then explain that watery discharge and mild cramps are expected.
- Advise aftercare: Ask the woman to avoid intercourse, tampons and douching until healing, and to report heavy bleeding or fever.
- Arrange follow-up: Schedule repeat screening, since persistent abnormality after treatment calls for colposcopy rather than repeat ablation.
Where the exam tries to catch you
Vignettes often test whether the student checks eligibility before choosing a treatment.
- Trap: Treating a lesion that extends into the endocervical canal or whose junction is not visible. Correct: Ablation cannot reach disease that is out of view, so colposcopy with excision is required.
- Trap: Ablating a pregnant woman with a positive visual test. Correct: Ablation is avoided in pregnancy, and the lesion is reviewed after delivery.
- Trap: Calling cryotherapy and thermal ablation equivalent in every respect. Correct: Both destroy tissue by temperature change, but thermal ablation generally produces less discharge and is preferred where the equipment is available.
Frequently asked questions
Who is eligible for cryotherapy in screen-and-treat?
Women with a fully visible lesion, a fully visible squamocolumnar junction and no suspicion of invasive cancer are eligible for cryotherapy in a screen-and-treat approach. Women who are pregnant, or whose lesion cannot be fully seen, need referral for further assessment instead.
What is the difference between cryotherapy and thermal ablation of the cervix?
Cryotherapy destroys cervical tissue by freezing it with a cold probe, while thermal ablation destroys it with heat. Thermal ablation generally causes less watery discharge and needs an electrical power source, so the choice depends on the equipment available.
What aftercare is advised after cervical cryotherapy?
Watery discharge for a few weeks is expected after cervical cryotherapy. Women are advised to avoid intercourse, tampons and douching until healing, commonly for about four weeks, and to return for follow-up.
When is excision needed rather than cryotherapy for the cervix?
Excision such as loop electrosurgical excision is needed when the lesion extends beyond view, the squamocolumnar junction is not fully visible or cancer is suspected. Cryotherapy and thermal ablation cannot assess tissue that is out of view, so they are not used in these cases.