Screening for Anal Cancer in Women

Abstract

Objective The incidence of anal cancer is higher in women than men in the general population and has been increasing for several decades. Similar to cervical cancer, most anal cancers are associated with human papillomavirus (HPV) and it is believed that anal cancers are preceded by anal high-grade squamous intraepithelial lesions (HSIL). Our goal was to summarize the literature on anal cancer, HSIL and HPV infection in women, and provide screening recommendations in women. Methods A group of experts convened by the ASCCP and the International Anal Neoplasia Society reviewed the literature on anal HPV infection, anal SIL and anal cancer in women. Results Anal HPV infection is common in women but is relatively transient in most. The risk of anal HSIL and cancer varies considerably by risk group, with HIV-infected women and those with a history of lower genital tract neoplasia (LGTN) at highest risk compared with the general population. Conclusions While there are no data yet to demonstrate that identification and treatment of anal HSIL leads to reduced risk of anal cancer, women in groups at the highest risk should be queried for anal cancer symptoms and have digital anorectal examinations to detect anal cancers. HIV-infected women and women with LGTN, may be considered for screening with anal cytology with triage to treatment if HSIL is diagnosed. Healthy women with no known risk factors or anal cancer symptoms do not need to be routinely screened for anal cancer or anal HSIL.

Anal cancer and anal cancer precursors in women with a history of HPV-related dysplasia and cancer

“…1 Anal cancer is strongly associated with high-risk (HR) HPV infection, and there is evidence that women with cervical HR-HPV are at increased risk for anal HR-HPV 2,3 . Women with persistent cervical HR-HPV infection may develop pathologic changes to cervical intraepithelial neoplasia (CIN) 3 or cancer.…”

Unsatisfactory exfoliative anal cytology samples, 15‐year experience with histologic, cytologic, and molecular follow‐up

“…Both of these anatomic regions are characterized by a squamo-columnar junction, the anatomic sublocation at which high grade cancer precursors are most likely to arise. While implementation of routine anal cancer screening for persons not at high risk of anal neoplasia would be unwise, targeted screening of patient populations in comparatively high risk groups would be of value in preventing invasive disease 9,10,16,17,[32][33][34]. While implementation of routine anal cancer screening for persons not at high risk of anal neoplasia would be unwise, targeted screening of patient populations in comparatively high risk groups would be of value in preventing invasive disease 9,10,16,17,[32][33][34].…”

Anal cancer in women: are we appropriately identifying the risks?

“…One option would be to embark on some form of screening programme; however, even within the subpopulations who are most at risk, it is difficult to fit anal cancer into the Wilson criteria. The current gold standard for identification of early anal malignancy is high-resolution anoscopy-guided biopsy—something which is too expensive to be used as a primary screening method, even in high-income countries 7. Anal cytology has a variable sensitivity and specificity, meaning that repeat screening would be necessary; something which is unlikely to be feasible for most groups—particularly given the relatively low prevalence of anal cancer 7.…”

“…The current gold standard for identification of early anal malignancy is high-resolution anoscopy-guided biopsy—something which is too expensive to be used as a primary screening method, even in high-income countries 7. Anal cytology has a variable sensitivity and specificity, meaning that repeat screening would be necessary; something which is unlikely to be feasible for most groups—particularly given the relatively low prevalence of anal cancer 7. Crucially, in many parts of the world, the lack of treatment options for anal cancer and the relative lack of data on management of precancerous anal lesions would render screening futile.…”