Distribution of human papillomavirus types in ThinPrep Papanicolaou tests classified according to the Bethesda 2001 terminology and correlations with patient age and biopsy outcomes.

BACKGROUND

A survey of the distribution of human papillomavirus (HPV) types across the spectrum of cervical cytologic categories defined by the Bethesda 2001 guidelines was conducted with the objective of examining how HPV detection by polymerase chain reaction (PCR) analysis may benefit the management of patients who have abnormal Papanicolaou (Pap) test results.

METHODS

DNA samples from women with no intraepithelial lesion or malignancy (NLM) (n = 300 samples); atypical squamous cells of undetermined significance (ASC-US) (n = 200 samples); low-grade squamous intraepithelial lesion (LSIL) (n = 200 samples); atypical squamous cells, cannot rule out high-grade squamous intraepithelial lesion (ASC-H) (n = 200 samples); and high-grade squamous intraepithelial lesion (HSIL) (n = 200 samples) were tested for HPV using a modified general primer (GP)5+/GP6+ PCR assay and dot-blot hybridization with type-specific oligonucleotide probes (PCR assay analytical sensitivity: 1-100 copies of HPV, depending on the HPV type, in a background of 100 ng human DNA).

RESULTS

HPV was detected in 27% of NLM samples, in 89.5% of ASC-US samples, in 97.5% of LSIL samples, in 93% of ASC-H samples, and in 96.5% of HSIL samples. Thirty-seven different HPV types were identified in total. One or more of 13 high-risk (HR) HPV types (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68) were detected in 53% of samples that were diagnosed as ASC-US (59.0% of patients younger than age 30 yrs; 45.5% of patients age 30 yrs and older), in 55.5% of samples that were diagnosed as LSIL (60.0% of patients younger than age 30 yrs; 44.0% of patients age 30 yrs and older), in 80% of samples that were diagnosed as ASC-H, and in 87.5% of samples that were diagnosed as HSIL (P < 0.001). HPV-16 was detected in 17.5% of ASC-US samples, in 15.5% of LSIL samples, in 48.5% of ASC-H samples, and in 49.0% of HSIL samples (P < 0.001). Among abnormal smears, HR HPV was significantly more common in women younger than age 30 years compared with women age 30 years and older (P < 0.002). Follow-up biopsy data were obtained for 359 patients. A "benign" biopsy result was recorded for 47 of 64 women (73.5%) with ASC-US, 30 of 66 women (45.5%) with LSIL, 39 of 87 women (45.0%) with ASC-H, and 26 of 142 women (18.0%) with HSIL and was most common in women age 30 years and older (P < 0.0001). Cervical intraepithelial neoplasia (CIN) Grade I (CIN-I) was found in 14.0% of women with ASC-US, in 39.5% of women with LSIL, in 8.0% of women with ASC-H, and in 7.0% of women with HSIL. CIN-II was diagnosed in 9.5% of women with ASC-US, in 13.5% of women with LSIL, in 19.5% of women with ASC-H, and in 24.0% of women with HSIL. CIN-III was identified in 2 women (3.0%) with ASC-US, in 1 woman (1.5%) with LSIL, in 24 women (27.5%) with ASC-H, and in 71 women (50.0%) with HSIL.

CONCLUSIONS

HR HPV testing by PCR of samples diagnosed according to the Bethesda 2001 guidelines may benefit the management of patients with ASC-US or patients with LSIL, especially among women age 30 years and older, by allowing exclusion from referral for biopsy of women who are negative for HR HPV types. However, the small numbers of women who had CIN-III detected after a diagnosis of ASC-US or LSIL limited the assessment of test sensitivity.