Keratosis reduces sensitivity of anal cytology in detecting anal intraepithelial neoplasia

Abstract

Objective. To identify factors that may contribute to poor sensitivity of anal cytology in contrast to the sensitivity of anoscopy in heterosexual women. Methods. We analyzed 324 patients with biopsy confirmed diagnosis of genital intraepithelial neoplasia (either vulva, vaginal, or cervical) from 2006 to 2011 who underwent both anal cytology and anoscopy. Cytology, anoscopy, and biopsy results were recorded. Biopsy specimens underwent independent analysis for quality of specimen. Also, biopsy specimens were analyzed for characteristics that may contribute to correlation, or lack thereof, between anal cytology and anoscopic directed biopsy.Results. 133 (41%) patients had abnormal anoscopy and underwent directed biopsy. 120 patients with normal anal cytology had anoscopy directed biopsies, resulting in 58 cases of AIN (sensitivity 9.4%; 0.039-0.199). This cohort was noted to have extensive keratosis covering the entire dysplastic anal lesion. 18 patients yielded abnormal anal cytology. Of these patients, 13 had anoscopic directed biopsies revealing 6 with AIN and absent keratosis (specificity 88.6%; 0.78-0.95). The κ statistic for anal cytology and anoscopy was −0.0213 (95% CI = −0.128-0.086).Conclusion. Keratosis reduces the sensitivity of anal cytology. Furthermore, anal cytology poorly correlates with anoscopy in the detection of AIN (κ statistic = −0.0213).© 2011 Elsevier Inc. All rights reserved. IntroductionThe National Cancer Institute estimates that 5,260 new cases of anal cancer were made in 2010. This constitutes a near doubling in the anal cancer rate over the past 10 years. The recently released Surveillance Epidemiology and End Results (SEER) report cites a statistically significant rise in the annual percentage change (APC) of 2.4 from 1992 to 2008 [1].Conversely, cervical cancer APC over the same time period is −2.7, largely attributable to improved screening modalities and guidelines [1]. Routine Pap smear screening has reduced the incidence of cervical cancer from 40 per 100,000 to 8 per 100,000. Because of this success, some have advocated anal intraepithelial neoplasia (AIN) screening using anal cytology at least in certain high risk population [2,3]. Risk factors for developing anal cancer, in both men and women, include anogenital human papillomavirus infection, anal receptive intercourse, multiple sexual partners, history of sexually transmitted disease, immunosuppression, and history of anal condyloma. Women with anal cancer are likely to have a prior history of cervical intraepithelial neoplasia or cervical carcinoma [4,5].Palefsky reported the sensitivity of anal cytology for detection of biopsy-proven AIN to be 69% in HIV-positive and 47% in HIV-negative men [6]. However, our study and others suggest that anal cytology is not a sensitive method for screening for AIN [5]. In our previous study, we evaluated 205 patients with genital dysplasia for both anal cytology and colposcopy. Anal cytology had a sensitivity of 8% and specificity of 94% in the diagnosis of AIN when compared to biopsy....

Performance of Anal Cytology Compared With High-Resolution Anoscopy and Histology in Women With Lower Anogenital Tract Neoplasia

“…The total number of biopsies was much higher in our study than in any of the previous studies, allowing us to evaluate correlations with features that might influence the performance of anal cytology. The concordance between anal cytology grades and anal histology was poor, as has previously been described [23].…”

“…There have been few studies specifically analyzing the performance of anal cytology in comparison with HRA/anal histology in high-risk women. The results have been conflicting, although most studies reported a very low sensitivity [17,23,24], with a small number of anal histological samples for comparison and, in most cases, a low rate of ASIL/AIN diagnosed. Information on features that might influence anal cytology has also been lacking [18].…”

Factors Associated with High-Grade Anal Intraepithelial Lesion in HIV-Positive Men in a Southern U.S. City

“…30 Finally, compared with cervical lesions, anal SIL can be markedly keratinized, which may result in decreased sensitivity for detecting HSIL on cytology. 31 Based on our findings, we suggest that any patient with HSIL cytology should be referred to anoscopy and not use repeat cytology for monitoring disease.…”

Prevalence of anal human papillomavirus infection and anal HPV-related disorders in women: a systematic review

“…Five of these 12 publications included a small number of HIV+ women, 20,21,40-42 one publication included a cohort of HIV-positive women with IN1-3 (compared with HIV-negative immune compromised and HIV-negative immune competent with IN1-3), 39 and two publications included a comparative cohort of women without a history of IN1-3. 43,44 Two publications included only women from the general population.…”