Biopsy follow-up of a cervical/vaginal smear interpretation of atypical glandular cells of undetermined significance (AGUS) most often reveals either a benign reactive process or a squamous cervical intraepithelial neoplasia (CIN) rather than a glandular one. The ThinPrep Papanicolaou test (TP) has been shown to increase diagnostic sensitivity for CIN. To the authors' knowledge there are few studies examining its effectiveness in diagnosing uterine glandular lesions, either endocervical or endometrial. The authors compared outcomes after AGUS interpreted in TP specimens and conventional smear preparations (CPs).
Follow-up was sought in all cases that were interpreted as AGUS during a 3-year period in which practice groups converted from CPs to TPs. A tissue diagnosis of adenocarcinoma in situ, CIN of Grade 2 or 3, or invasive carcinoma was considered to be a positive follow-up result. Either a benign biopsy finding with a subsequent benign cytologic result or two consecutive benign cytologic results were considered to be negative follow-up results.
AGUS was reported in 116 of 75,002 TPs (0.15%) and 151 of 79,322 CPs (0.19%). Follow-up information was available in 91 (78%) and 130 (86%) cases, respectively. The predictive value of AGUS for a positive follow-up result was 22% in the TP group and 15% in the CP group. An AGUS interpretation with a positive follow-up result was found in 0.027% of all cases using TPs and in 0.025% of all cases using CPs.
The use of TPs may increase the diagnostic specificity of AGUS for a high-grade precursor lesion or carcinoma.