Is there a role for the thinprep imaging system in reporting anal cytology?

Area of Science:

• Cytopathology
• Gastroenterology
• Oncology

Background:

• The ThinPrep Imaging System (TIS) is an established, accurate, and time-saving method for cervical cytology screening.
• Anal and cervical cytology share morphological similarities, suggesting TIS's potential applicability to anal cytology.
• This study evaluated TIS performance on anal ThinPrep slides within a cohort of homosexual men participating in a human papillomavirus (HPV)-related anal abnormality natural history study.

Purpose of the Study:

• To assess the performance and utility of the ThinPrep Imaging System (TIS) for the cytological analysis of anal samples.
• To compare TIS classification of anal cytology slides with traditional manual screening methods.
• To evaluate TIS effectiveness in identifying high-grade squamous intraepithelial lesions (HSIL) in anal samples.

Main Methods:

• Four hundred nineteen anal cytology slides were processed using the TIS.
• Slides were classified by TIS as either 'No further review' (archived) or 'Manual review' (requiring full manual screening).
• TIS results were compared against original manual screening reports, with a specific focus on cases with concurrent biopsy-confirmed HSIL.

Main Results:

• Out of 419 slides, 176 (42.0%) were classified by TIS as 'No further review'.
• A trend of decreasing 'No further review' classifications was observed as the severity of cytological abnormality increased.
• Eighty-two of 92 (92.1%) slides with biopsy-confirmed HSIL and cytological abnormality were flagged for 'Manual review', including all 45 (100%) with cytological HSIL.

Conclusions:

• The TIS cervical algorithm demonstrated optimal performance on anal samples when both cytological and histological evidence of HSIL were present.
• The classification of 27.7% of unsatisfactory slides as 'No further review' suggests potential differences in criteria needed for anal cytology compared to cervical cytology.
• Due to the high prevalence of anal abnormalities and the resulting high proportion of slides requiring manual review, the time-saving potential of TIS for anal screening may be less favorable than in cervical screening.