Background and aims: Majority of cases of anal squamous cell carcinoma are human papilloma virus (HPV)-induced and result from anal intraepithelial neoplasia (AIN). This study was conducted to examine methods which may enable the routine diagnosis of HPV-induced changes in the anal rim and the consequences of such detection especially in view of a more sensitive diagnosis of AIN. Results were clinically correlated.
Methods: The study included biopsy samples from 87 patients who had been diagnosed with the following disease patterns: 47 invasive anal carcinoma, 33 AIN of varying severity and seven condylomatous lesions. In 52 of these cases, a tumour was clinically suspected. All biopsies were retrospectively examined for microscopic indications of HPV infection. After microdissection, additional HPV analysis via PCR was carried out.
Results: In 38 of 47 cases of anal carcinoma, HPV DNA could be detected via PCR (80.9%), the majority of which were HPV 16 (33/38=86.8%). In 29 of the 33 cases of AIN, HPV DNA was detected (87.9%), most of these in AIN III (15/16=93.8%). Histological markers of HPV infection were detected in all 87 cases.
Discussion: In our series, the clinical diagnosis of the invasive anal carcinoma had a high sensitivity of 93.6%, with a specificity of 80%. The positive predictive value was 84.6%, and the negative predictive value 91.4%. In contrast, AIN had been detected clinically in none of the cases. In this situation, especially with high-risk patients, our findings recommend anal HPV screening in combination with anal cytology and anoscopy.
Conclusion: Based on our results, we urgently recommend for any histological report on excision of anal lesions to include a statement whether histological markers of HPV infection were detected. In individual cases, validation via HPV PCR must be considered.