Predictive value of diagnoses of endocervical glandular abnormalities in cervical smears.

Aims: To determine the positive predictive value (PPV) of cervical smear diagnoses of 'definite' and 'possible' endocervical adenocarcinoma in situ or invasive adenocarcinoma, and whether diagnostic accuracy can be improved.

Methods: The study examined cervical smears reported as definite or possible high-grade glandular abnormality between 1992 and 1998. PPV was calculated by comparing smear diagnoses with the subsequent histopathology report. All available smears were reviewed without knowledge of follow-up results, and were reclassified by consensus.

Results: Thirty-two smears were diagnosed as high-grade glandular lesions, with adequate biopsy follow-up in 31 cases (96.9%). A high-grade epithelial abnormality (HGEA) was detected in 29 cases (PPV, 93.5%), with a high-grade glandular lesion in 24 (PPV, 77.4%). Very few smears were reclassified on review. Seventy-three smears were initially diagnosed in the 'inconclusive' glandular or indeterminate cell-type category. There was adequate biopsy follow up for 54 cases (74.0%). On follow-up, 31 cases had a HGEA (PPV, 57.4%), with 14 cases having a high-grade glandular abnormality (PPV, 25.9%). In the review of 'inconclusive' smears, 12 were reclassified as squamous abnormalities and none of these had a glandular lesion on biopsy. Eight were reclassified as negative; seven contained endometrial stroma and the glandular cells in question were considered to be of lower uterine segment (LUS) origin. No significant lesion was present on follow-up of these cases.

Conclusions: For clinicians using our laboratory, large loop excision of the transformation zone (LLETZ) or cone biopsy should follow a 'definite' cytological diagnosis of a high-grade endocervical glandular lesion. However, cone biopsy may not be the appropriate initial management in the 'possible' high-grade glandular group because of a significantly lower predictive value of the diagnosis. The slide review highlighted the importance of (1) caution in classifying sheets of abnormal cells as glandular, and (2) endometrial stroma as a marker of LUS material.