Correlation of Abnormal Pap Smears with Histopathologic Results: Philippine General Hospital Experience (2014-2017)
Objectives. To evaluate abnormal Papanicolau smear results at the Philippine General Hospital (PGH) for the past four years by comparing abnormal smear cytology with histologic interpretations. Possible causes of discrepant results were also determined.
Methods. All Pap smears released as abnormal from January 2014 to December 2017 and the corresponding available biopsies were retrieved. Discrepancy between cytologic and histology diagnosis was assessed and pairs with major discordance were reviewed.
Results. There were a total of 30,237 conventional pap smears signed out of which 239 (0.79%) were abnormal and only 56 (23%) had a subsequent tissue biopsy. The overall concordance rate is 75% while strict or absolute concordance rate is 32%. The overall discordance rate is 25%. Positive predictive value is highest for pap smears signed out as atypical glandular cells favor neoplastic (AGC-NEO) (100%), followed by malignant (93%), high grade squamous intraepithelial lesion (HSIL) (83%), and then atypical squamous cells cannot exclude an HSIL (ASC-H) and atypical squamous cell of undetermined significance (ASCUS), both at 67%.
Conclusions. Considering that the Philippine General Hospital is a referral and academic center, we have a low percentage of abnormal pap smears compared to other developing countries and even a lower percentage of patients who had subsequent biopsies. Cytohistologic correlation detected interpretative as well as sampling errors, and the aim is to work on these deficiencies by improving quality assurance protocols and modifying current local practices of both pathologists and clinicians.