Cervical Cytology: An Audit in a Singapore Teaching Hospital

TP Thamboo, M Salto-Tellez, KB Tan, B Nilsson, A Rajwanshi
Correspondence: Dr Thomas Paulraj Thamboo, pattpt@nus.edu.sg

ABSTRACT
Objectives To describe the cervical cytology diagnoses and cyto-histological correlation in the Department of Pathology, National University of Singapore in 1997 and to compare the data with international figures.
Methods A database search of all cervical cytology cases diagnosed in the department in 1997 as well as follow-up biopsies was carried out. The data was then critically analysed.
Results 10,207 cases were reviewed. 96% of the cases had a diagnosis of "negative". Under 1% of cases were labelled as "inadequate". "Atypia" was diagnosed in 1% and dysplasia and/or malignancy was diagnosed in 1%. These figures correlate well with international data. Of the dysplasia cases, 78% were followed by biopsy. Of the high-grade dysplasia cases that were biopsied, 97% of the biopsy diagnoses were within the acceptable concordance range with the cytology diagnoses and in only 3% was there a significant discrepancy. Of the cases diagnosed as atypia, 39% were subsequently biopsied at the same institution as the next procedure and only one showed high grade dysplasia. A total of six cases showed a significant discrepancy between the cervical cytology result and the subsequent biopsy diagnosis and these were reviewed to elucidate the reasons for the discrepancies.
Conclusion The cervical cytology service is of a high diagnostic standard. A subset of patients is probably being prematurely biopsied and may benefit from having a repeat smear instead. Specific clinical protocols regarding subsequent therapy following cytology results and closer cyto-histological correlation are two main areas where the cytology service can be improved.

Keywords: cervix, cytology, review, screening, ASCUS
Singapore Med J 2003; 44(5): 256-260