Examining the Evidence
Do women who have CIN 3 face an elevated risk of Ca after treatment?
Yes. This prospective cohort study from Sweden found a higher risk of invasive cervical cancer and vaginal cancer in women who had been treated for cervical intraepithelial neoplasia (CIN) 3. The study included all women in Sweden who were treated for severe dysplasia or cervical carcinoma in situ—equivalent to CIN 3—from 1958 to 2002, a total of 2,315,724 woman-years of follow-up. The standardized incidence ratio for invasive cervical cancer in women treated for CIN 3, compared with the general population, was 2.34 (95% confidence interval, 2.18–2.50). The relative risk of vaginal cancer also was high, exceeding 6. Women faced an even higher risk if they were older than 50 at treatment.
The risk of cancer decreased over time, but was still elevated 25 years after treatment.
Newly updated consensus guidelines for posttreatment management of women with CIN 2,3 recommend human papillomavirus (HPV) testing at 6 to 12 months.1 Surveillance using cytology or a combination of cytology and colposcopy at 6-month intervals also is acceptable. Women who have a positive test should undergo colposcopy and endocervical sampling. Women who have a negative HPV test or two consecutive negative Pap tests after treatment should be screened annually for at least 20 years. These recommendations were based on data that showed a higher incidence of recurrent disease and invasive cancer in women previously treated for high-grade dysplasia. This excellent study by Strander and associates confirms those recommendations.
Women who were treated from 1991 to 2000 had a risk of cancer and neoplasia almost twice as high as that of women treated from 1958 to 1970. Excision procedures became the main treatment for dysplasia after 1980 (replacing hysterectomy). Increased prevalence of HPV infection also may have a greater effect on women who have been treated for CIN than on the general population, who may be more immune competent.
In this study, it was not possible to link cervical or vaginal cancers with the specific method of treatment of CIN 3
What this evidence means for practice
This study confirms recommendations of the 2006 Consensus Conference for long-term surveillance of women treated for CIN 3.1 Those recommendations are at odds, however, with guidelines issued by the American College of Obstetricians and Gynecologists, which state: “Women who have had a hysterectomy and have a history of CIN 2 or CIN 3—or in whom a negative history cannot be documented—should continue to be screened annually until three consecutive satisfactory negative cervical cytology results are obtained. Routine screening may then be discontinued.”2 It has been my practice to continue to screen women even after hysterectomy if they have a history of high-grade dysplasia. The American Cancer Society also recommends continued screening after hysterectomy in women who have been treated for cervical dysplasia or cancer.
1. Wright TC, Jr, Massad LS, Dunton CJ, Spitzer M, Wilkinson EJ, Soloman D. 2006 consensus guidelines for the management of women with cervical intraepithelial neoplasia or adenocarcinoma in situ. Am J Obstet Gynecol. 2007;197:340-345
2. Cervical Cytology Screening. Practice Bulletin No. 45. Washington, DC: ACOG; 2003.