CHAPTER 4: SCREENING FOR CERVICAL CANCER

136 Chapter 5: Diagnosis and Management of Precancer5Chapter 5: Diagnosis and Management of PrecancerCryotherapyCryotherapy eliminates precancerous areas on the cervix by freezing them. Thisrelatively simple procedure takes about 15 minutes and can be performed onan outpatient basis. It involves applying a highly cooled metal disc(cryoprobe) to the cervix, and freezing its surface using carbon dioxidePS12(CO2) or nitrous oxide (N2O) gas. The cryoprobe is applied to the cervixtwice, for three minutes each time, with a 5-minute thaw in between Cryotherapy(double-freeze technique). A continuous supply of carbon dioxide ornitrous oxide is required. The more expensive, bone-dry medical grade of gas ispreferred, but industrial-grade gas can be used if that is what is locally availableand affordable. Cryotherapy is highly effective for the treatment of small lesions, butfor larger lesions the cure rate is below 80%. Because the area of the cervix that isfrozen has very few nerve endings, cryosurgery is generally associated only with somecramping or mild pain. It can, therefore, be done without anaesthesia.ProvidersCryotherapy can be performed at all levels of the health care system by a variety oftrained providers (doctors, nurses, midwives) skilled in pelvic examination, and trainedin cryotherapy as an outpatient procedure.Indications and exclusion criteriaEligibility criteria• Positive screening test for cervicalprecancer• Lesion small enough to be covered bythe cryoprobe with no more than2 mm beyond its edges• The lesion and all edges fully visiblewith no extension into the endocervixor onto the vaginal wallExclusion criteria• Evidence or suspicion of invasivedisease or glandular dysplasia• The lesion extends more than 2 mmbeyond the cryoprobe edge• Pregnancy• PID (until treated)• Active menstruation