Cryotherapy, Laser Vaporization, and Loop Electrosurgical Excision for Treatment
Cryotherapy, Laser Vaporization, and Loop Electrosurgical Excision for Treatment of Squamous Intraepithelial Lesions of the Cervix
abstract & commentary
Synopsis: This randomized trial demonstrates that cryotherapy, laser vaporization, and loop electrosurgical excision have similar results for the treatment of CIN.
Source: Mitchell MF, et al. Obstet Gynecol 1998; 92:737-744.
The purpose of this study was to determine whether there were differences in the effectiveness of treatment of CIN using cryotherapy, CO2 laser vaporization, or loop electrical excision. Only women with biopsy-proven CIN lesions who were 18 years or older were eligible for enrollment. Other appropriate exclusions were made (e.g., pregnancy, etc.). Four hundred ninety-eight patients were randomly assigned to each of the three treatment methods. Participation involved random assignment, treatment, and follow-up at 1, 4, 8, 12, 16, 20, and 24 months post therapy. Mitchell and associates were interested in the rates of complication, persistent disease, and recurrent CIN. 108 women were excluded, largely because of inadequate follow-up. The final comparisons were made on the 390 women who were followed for a mean duration of 16 months.
The cryotherapy patients underwent a double freeze using two three-minute treatments with a period of thawing (time not specified). The CO2 laser group was treated with 20 watts of laser energy and a 1 mm spot size, to a depth of 8 mm at the canal margin. The loop excision patients were treated with a 20 mm × 8 mm loop. All patients were treated in an outpatient clinic. Appropriate training and pathology review were performed. The procedures and the follow-up were handled in a consistent fashion. After randomization, there were no statistically significant differences in the distribution of severity of CIN, lesion size, patient age, HPV positivity, history of prior treatment, or smoking history.
Table 1 shows the overall complication, disease persistence, and disease recurrence rates for the three methods of therapy. There were no statistically significant differences among the three methods for these three endpoints. However, persistence of disease (regardless of treatment method) was 19-fold more common with large lesions (> 2/3 of the surface of the cervix involved with CIN). Recurrent disease was more common among women 30 years of age or older, women who were HPV positive, and women who had previously been treated for CIN.
| Table | |||
| Complication, Disease Persistence, and Disease Recurrence Rates | |||
|
|
|
|
|
| Complication |
|
|
|
| Persistence |
|
|
|
| Recurrence |
|
|
|
| Modified from Mitchell MF, et al.
_________________________________________________ |
|||
Comment by Kenneth Noller, MD
For many years, those of us who have been teaching colposcopy courses have preached that there is virtually no difference in success rates among the three methods of office therapy studied in this paper. Finally, a well designed, prospective, randomized study has been completed that proves that we had made the correct inference based on smaller, non-randomized studies. However, there is at least one piece of important new information. It has been known for some time that large CIN lesions are poorly treated by cryotherapy. Therefore, that method usually is not used with three or four quadrant lesions, with CO2 laser vaporization, or loop excision being preferred. This article clearly demonstrates that there is an increased treatment failure rate with large lesions, regardless of the method of therapy.
Many of us work in areas with virtually complete penetration of the market by managed care organizations. Some of us are unfortunate enough to work in areas where capitation is the major method by which these organizations pay for physician services. In areas such as ours, we must constantly look at the cost (not charge) for various procedures and, when several procedures are equally effective, choose the least expensive. This article demonstrates that the preferred method for treatment of CIN in a managed care, capitated environment would be cryotherapy because of its low cost. If a CO2 laser is available in the outpatient clinic the cost of using that instrument would also be low. The most expensive procedure because of the large number of disposables and the pathology cost is loop electroexcision. Of the three therapies, my personal favorite is loop excision, but more and more I am reserving its use for patients with CIN III and using cryotherapy and office CO2 laser for CIN II. (Long-time readers know that I rarely, if ever, treat CIN I.)
Subscribe Now for Access
You have reached your article limit for the month. We hope you found our articles both enjoyable and insightful. For information on new subscriptions, product trials, alternative billing arrangements or group and site discounts please call 800-688-2421. We look forward to having you as a long-term member of the Relias Media community.