In 1998 a multi-institution RCT established that Cryoablation (CRYO) performed non-inferiorly to LEEP for the treatment of CIN I-III, with a less than 20% difference in subsequent persistent dysplasia. In 2006 and 2013, the ASCCP recommended either excision or ablation for CIN II-III. Our institution offered CRYO for treatment of moderate dysplasia in 2010. We aimed to verify that CRYO at our military institution had similar effectiveness to published standards.METHODS:
This was a retrospectively analyzed cohort trial. We included patients with new onset, ECC negative or unknown, CIN II that received intervention from 2010 to 2014. Post-treatment presence of persistent dysplasia was defined as CIN I-III, or persistent HPV+ status. Subsequent procedures were documented. A power analysis using the Chi squared statistic revealed 77 patients in each arm would establish non-inferiority of 20%. Results were analyzed with Chi Squared and Fisher's exact test.RESULTS:
Between 2010 and 2014, 191 patients fulfilled study criteria: 70 CRYO and 121 LEEP patients. 9% are less than 1 year from intervention, and 12% left the military medical system before follow up PAP. 29% CRYO versus 20% LEEP (P=.36) had post-treatment persistent dysplasia. Only 4% CRYO versus 8% LEEP (P=.48) have required subsequent excisional procedures.CONCLUSION:
At time of analysis there are insufficient CRYO patients to confirm that our institution's CRYO success rate is comparable to Mitchell et al's (1998) precedent. It is reassuring that at less than 80% patient accrual, our results trend toward non-inferiority between the two techniques.