Significance of cytopathologist's review of Pap tests screened as negative for intraepithelial lesion or malignancy that are positive for high-risk human papillomavirus

Rescreening of high-risk HPV positive Papanicolaou tests initially screened as negative is a low yield procedure in the era of HPV genotyping

INTRODUCTION

Many laboratories rescreen Papanicolaou test slides initially interpreted as negative, but positive for human papillomavirus (HPV) high-risk types, as a quality control measure. We have evaluated the utility of this practice in the era of HPV genotyping as a laboratory improvement project.

MATERIAL AND METHODS

Between August 2016 and October 2019, we identified 3618 rescreened Papanicolaou tests with follow-up biopsies. The biopsy results were put into 3 groups: 1) Negative; 2) LSIL: HPV changes or low-grade squamous intraepithelial lesion; and 3) HSIL: high-grade squamous intraepithelial lesion or carcinoma. HPV molecular testing results with subtyping for types 16 and 18 were available for 3117 of these cases.

RESULTS

A total of 530 of 2812 Papanicolaou tests (18.8%) with positive HPV results were reinterpreted as cytologically abnormal after rescreening; 75 (14.2%) had a biopsy result of HSIL. The subset positive for HPV types 16/18 had 38 of 133 cytology positive cases diagnosed as HSIL on biopsy vs. 107 of 935 cytology negative cases diagnosed as HSIL on biopsy (28.6% vs. 11.4%, P < 0.0001). The subset positive for "other" (non-16/18) high-risk HPV types had 37 of 397 cytology positive follow-up HSIL vs. 84 of 1288 cytology negative follow-up HSIL (9.3% vs. 6.5%, P = 0.075).

CONCLUSIONS

Rescreening has the highest yield in specimens positive for types 16/18. However, for this group colposcopy is recommended regardless of cytology findings, reducing the patient benefit. Routine rescreening of cytology negative/HPV positive Papanicolaou tests has reduced utility when HPV subtyping is performed and should be reconsidered.