False-Negative Interpretation of Adenocarcinoma In Situ in the College of American Pathologists Gynecologic PAP Education Program

Abstract

Context.— Adenocarcinoma in situ (AIS) is difficult to correctly interpret on Papanicolaou (Pap) cytology slides and false-negative interpretations of AIS can cause significant problems in daily practice. Objective.— To investigate the false-negative interpretation rate of AIS and the factors related to false-negative interpretation through responses in an educational environment. Design.— We retrospectively evaluated 11 337 responses in the PAP Education Program (PAP-Edu) from 173 AIS slides from 2011 to 2015. The false-negative interpretation rate, most common false-negative interpretations, and related other factors were evaluated. Results.— The overall false-negative rate was 6.9% (784 of 11 337). Respondents correctly interpreted AIS 50.0% (5667 of 11 337) of the time; high-grade intraepithelial lesion (HSIL) and malignancies (adenocarcinoma, squamous cell carcinoma, and other carcinomas) accounted for 42.7% (4842 of 11 337) and low-grade intraepithelial lesion accounted for 0.4% (44 of 11 337) of responses. Overall, 92.7% (10 509 of 11 337) of responses were HSIL and above. Among 784 false-negative responses, negative for intraepithelial lesion or malignancy was the most common (61.5% [482 of 784]), followed by reparative changes (24.1% [189 of 784]) and atrophic vaginitis (7.7% [60 of 784]). Overall, pathologists' responses showed a significantly higher false-negative rate than cytotechnologists' responses (8.3%, 403 of 4835 versus 5.7%, 275 of 4816; P < .001). The false-negative response rates were not statistically different among preparation types. Conclusions.— The low correct interpretation rate and higher false-negative rate for AIS demonstrate the difficulty in interpreting AIS on Pap cytology, which may cause clinical consequences. The higher false-negative rate with pathologists than with cytotechnologists suggests cytotechnologists' higher screening sensitivity for AIS or cautious interpretation to avoid false-positive results by pathologists.