Follow-up Findings for Women with Human Papillomavirus-Positive and Atypical Squamous Cells of Undetermined Significance Screening Test Results in a Large Women’s Hospital Practice (Report)

Follow-up Findings for Women with Human Papillomavirus-Positive and Atypical Squamous Cells of Undetermined Significance Screening Test Results in a Large Women's Hospital Practice (Report)

Equivocal “atypical” cytologic abnormalities have been recognized far back as Papanicolaou’s original class system classification (Class II). (1) The 1991 Bethesda System (TBS) introduced the term atypical squamous cells of undetermined significance (ASC-US) and proposed standardized criteria for this abnormal interpretation, even while acknowledging that “use of this term by pathologists may differ,” (2) an observation resoundingly confirmed in inter-observer reproducibility studies. (3) Atypical squamous cells of undetermined significance quickly became the most frequent abnormal interpretation in cervical cytology (4); it clearly reflects a substantial degree of interpretive uncertainty. This category was originally proposed to encompass “cellular abnormalities that are more marked than those attributable to reactive changes but that quantitatively or qualitatively fall short of a definitive diagnosis of squamous intraepithelial lesion (SIL).”2 Despite limited reproducibility, the lower abnormal threshold for an interpretation of ASC-US appears to have been useful in broadening the abnormal cytologic screening net and in helping to potentially maximize Papanicolaou (Pap) test sensitivity for detection of underlying precancer (5,6) or even of invasive cancer. (7) Data from the ASCUS/low-grade squamous intraepithelial lesion (LSIL) Triage Study (ALTS), (8) based on entry community, conventional Pap smear results, provided crucial support for consensus guideline recommendations (9,10) favoring reflex high-risk human papillomavirus (hrHPV) DNA testing as the most cost-effective method for risk stratification of women with an ASC-US Pap finding. (11) However, even as reflex hrHPV DNA testing subsequently became the most common follow-up method for women with ASC-US Pap test findings, (12) the definition of ASC US shifted in The Bethesda System 2001 (TBS2001) (13) and liquid-based cytology (LBC) largely replaced conventional Pap smears. The Bethesda System 2001 simultaneously eliminated the category ASC-US favor reactive (ASCUSR), encouraged pathologists “to judiciously downgrade a portion” of ASCUS-R cases, and separated from ASC-US a subset of ASC cases referred to as ASC-H (atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesion).”

Follow-up Findings for Women with Human Papillomavirus-Positive and Atypical Squamous Cells of Undetermined Significance Screening Test Results in a Large Women's Hospital Practice (Report)

Follow-up Findings for Women with Human Papillomavirus-Positive and Atypical Squamous Cells of Undetermined Significance Screening Test Results in a Large Women’s Hospital Practice (Report) | | 4.5