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Thursday, August 8, 2013

Trailers (55): Anal intraepithelial neoplasia in women with genital dysplasia

ElNaggar and Santoso. Risk factors for anal intraepithelial neoplasia in women with genital dysplasia.

Why should you read about this topic?

Incidence of anal cancer in women is on the rise.  Estimating risk for anal intraepithelial neoplasia may identify a cohort of women who would benefit from screening for pre-malignant lesions or early anal cancer.

What were the authors trying to do?

Develop a model for estimating risk for anal intraepithelial neoplasia in women.

Who participated and in what setting?

Women (N=327) with genital intraepithelial neoplasia referred to the University of Tennessee-West Gynecologic Oncology Division between 2006-10

What was the study design?

Cross-sectional descriptive study

What were the main outcome measures?

High-resolution anoscopy-guided biopsy-proven anal intraepithelial neoplasia

What were the results?

Prevalence was 19.6% in this sample.  Sensitivity of anal cytology was only 11.9%.  Multivariable analysis yielded a model that included a history of anal sex, immunosuppression, and VIN.  Having no or one risk factor indicated a negative predictive value of 88.2%.  Having any two risk factors provided a positive predictive value of 43%.

What is the most interesting image in the paper?

Table 4

What were the study strengths and weaknesses?

Strengths: all participants underwent high-resolution anoscopy; the large majority were evaluated with both cytology and anoscopy.  Weaknesses: unclear definition of immunosuppression; convenience sample may limit generalizability.

What does the study contribute for your practice?

Not sure.  If you’re lucky enough to have someone who can do high-resolution anoscopy, why wouldn’t you do it on everyone with genital intraepithelial neoplasia?  After all, the negative predictive value of the model was only 88.2%, not much different from the 80.4% unaffected rate in the sample.