ABSTRACT
OBJECTIVE: The current method for screening anal cancer is anal cytology, which has low sensitivity. Since high-risk human papillomavirus (HR-HPV) is associated with almost 90% of cases of anal cancer, the objective of this study is to evaluate whether testing for HR-HPV can optimize the screening. DESIGN: Prospective study with patients enrolled in a screening program for anal dysplasia. Considering high-resolution anoscopy (HRA)-guided biopsy as the gold standard for diagnosis of high-grade squamous intraepithelial lesions, the diagnostic performance of anal cytology, HR-HPV testing, and the combination of both was calculated. SETTINGS: A single center for anal dysplasia. PARTICIPANTS: A total of 364 patients (72% males, 82% HIV-positive). INTERVENTION: Patients underwent anal cytology, HR-HPV test, and HRA-guided biopsy of the anal canal. MAIN OUTCOME MEASURES: Ability of cytology and HR-HPV test (individually and combined) to detect high-grade squamous intraepithelial lesions, and analysis of the cost of each diagnostic algorithm. RESULTS: Cytology alone was the cheapest approach, but had the lowest sensitivity [59%, 95% confidence interval (CI) 46-71%], despite of highest specificity (73%, 95% CI 68-78%). Cotesting had the highest sensitivity (85%, 95% CI 74-93%) and lowest specificity (43%, 95% CI 38-49%), and did not seem to be cost-effective. However, HR-HPV testing can be used to triage patients with normal and atypical squamous cells of undetermined significance cytology for HRA, resulting in an algorithm with high sensitivity (80%, 95% CI 68-89%), and specificity (71%, 95% CI 65-76%), allied to a good cost-effectiveness. CONCLUSION: HR-HPV testing is helpful to optimize the screening in cases of normal and atypical squamous cells of undetermined significance cytology.
Subject(s)
Alphapapillomavirus , Anus Neoplasms , HIV Infections , Papillomavirus Infections , Anus Neoplasms/diagnosis , Early Detection of Cancer , Female , HIV Infections/diagnosis , Humans , Male , Papillomaviridae , Papillomavirus Infections/diagnosis , Prospective StudiesABSTRACT
PURPOSE: The purpose of this study was to analyze the agreement between anal Pap smear and high-resolution anoscopy-guided biopsy in diagnosing anal dysplasia in HIV-infected patients. METHODS: We conducted cross-sectional analysis of HIV-infected patients receiving anal dysplasia screening as part of routine care. Agreement between measures was estimated by weighted kappa statistics, using a three-tiered cytologic and histologic grading system (normal, low-grade dysplasia, and high-grade dysplasia). Estimates of sensitivity, specificity, and predictive values were calculated using a two-tiered cytologic and histologic grading system ("without dysplasia" and "with dysplasia of any grade"). Estimates were also calculated for the detection of high-grade dysplasia. RESULTS: During a one-year period, 222 patients underwent 330 anal Pap smears followed by high-resolution anoscopy-guided biopsies. There were 311 satisfactory Pap smears with concurrent biopsies. Considering histology the standard, the frequency of anal dysplasia was 46%. Kappa agreement between anal Pap smear and biopsy was 0.20. For detection of anal dysplasia of any grade, anal Pap smear showed sensitivity of 61%, specificity of 60%, positive predictive value of 56%, and negative predictive value of 64%. For high-grade dysplasia, anal Pap smear showed sensitivity of 16% and specificity of 97%. CONCLUSION: Anal Pap smears alone were not sensitive enough to rule out anal dysplasia. We recommend that high-resolution anoscopy-guided biopsy be incorporated as a complementary screening test for anal dysplasia in high-risk patients. Following baseline high-resolution anoscopy, these individuals could be followed with serial anal cytology to dictate the need for future high-resolution anoscopy-guided biopsies.
