Role of HPV Testing in Anal Pap Tests

Abstract

Introduction: The National Cancer Institute reports an annual anal cancer incidence of 1.6 per 100,000 in the general population. Men who have sex with men (MSM) have a much higher incidence ranging 35-100 per 100,000 with increased incidence in HIV-infected patients. The causal connection between HPV infection and squamous epithelial lesions has been well documented. Based on experience for cervical cancer screening, anal Pap tests (PT) are now used to screen for squamous intraepithelial lesions in high risk patients. Materials and Methods: We studied 241 anal PT obtained from 151 HIVpositive male patients (MSM) attending the Veterans Affairs Medical Center in Washington DC obtained between 2006 and 2012. PTs were reported using the 2001 Bethesda system terminology (NILM, ASC-US, ASC-H, LSIL, HSIL, SCC). Our institution has been among many others to use the LSIL-H (low grade squamous intraepithelial lesion, cannot exclude a high grade squamous lesion) as a diagnostic category. We evaluated the follow up of patients with abnormal cytology, including repeat cytology and biopsy. Results: Of the 241 anal PT performed, 184 (77%) of the smears were considered satisfactory for evaluation. 44 cases (18%) were negative, 140 (58%) were abnormal. Of these 140 abnormal PT, 79 (56.4%) had cytologic (repeat PT) or histologic (biopsy under anoscopy) follow up (see Table 1). Among these 79 patients, 43 (54%) had a biopsy-proven dysplasia (low grade, high grade and SCC). 19 (24%) had LSIL or higher on repeat Pap. Conclusions: The high number of patients with no follow-up may be a bias of the population targeted in this study (MSM, homelessness, other socioeconomic and educational factors). The high rate of abnormal results described in this study and in the literature reinforces the need for aggressive screening and clinical follow up, as well as national guidelines for screening and follow-up.