Predictive value of the anal cytology for detecting anal intraepithelial neoplasia or worse: A systematic review and meta-analysis

Background Anal intraepithelial neoplasia (AIN) refers to a precancerous lesion of anal squamous cell carcinoma (SCC). Human papillomavirus (HPV) is considered a crucial risk factor for AIN. Individuals with high-risk sexual behaviour, such as receptive anal intercourse and multiple sexual partners, as well as men who have sex with men exhibit a relatively high rate of AIN. The anal cytology is a screening method for AIN in high-risk individuals, and patients with abnormal anal cytology may benefit from high-resolution anoscopy. This study explored the predictive value of the anal cytology for the detection of AIN or worse (AIN+). Methods We searched the databases of PubMed, BioMed Central, Cochrane Library, and Google Scholar for relevant studies. Studies on the diagnostic efficacy of the anal cytology for predicting anal cancer on a per-patient basis were included. We excluded review articles. Either prospective trials or retrospective studies were included. We performed the meta-analysis by using a random-effects model to generate a pooled sensitivity, specificity, and diagnostic odds ratio (DOR). All analyses were performed using the MetaDiSc version 1.4 software (Universidad Complutense, Madrid, Spain). Results Twelve studies with 2541 participants were retrieved. The meta-analysis of the studies assessing the predictive value of the anal cytology for detecting AIN+ generated a pooled sensitivity of 0.79 (95% confidence interval [CI], 0.77-0.82) and a pooled specificity of 0.66 (95% CI, 0.64-0.69). The pooled DOR for the anal cytology was 5.31 (95% CI, 3.31-8.49). Conclusions Our results revealed that the anal cytology might be effective in diagnosing AIN+.