Prevalence and pattern of human papillomavirus infection in females, with cytology correlation: the Hong Kongexperience

Abstract

Objectives To analyze the prevalence and pattern of HPV infection in women of different age groups in Hong Kong, with respect to liquid-based cytologic diagnosis.

Materials and Methods A total of 2,055 liquid-based gynecologic cytology cases using either SurePath or ThinPrep during the period from July 1, 2007 to July 31, 2012 were retrieved from the archival files of CH Pathology Limited for retrospective analysis. Cytologic diagnosis was first given. Polymerase chain reaction (PCR)-based human papillomavirus (HPV) genotyping was subsequently performed in cases either as requested simultaneously by gynecologists or if the cytologic diagnosis was “atypical squamous cells of undetermined significance (ASC-US)” or above. IBM SPSS statistics 20 was used for data analysis and assessment of possible statistical significance.

Results The overall prevalence of HPV infection in the studied population was 67.7%, with 37.2% cases with “negative” cytologic findings being HPV positive. Cases with “lowgrade squamous intraepithelial lesion (LSIL)”, “atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesion (ASC-H)” and “high-grade squamous intraepithelial lesion (HSIL)” were highly associated with HPV infection (97.8%, 91.5% and 98.4%, respectively). Amongst the “ASC-H” and “HSIL” cases, most of them were shown to harbor high-risk HPV DNA (87.2% and 93.4%, respectively).

The overall prevalence of HPV infection was higher in women younger than 25 years and in women older than 54 years, with the peak at post-menopausal age group. The patterns for infection by single HPV genotype or high-risk HPV genotype(s) alone were similar to the overall pattern, with the first peak at women younger than 25 years, followed by a drop at aged 25 to 34 and rebound again when age afterward. As for infection by multiple HPV genotypes or low-risk HPV genotype(s) alone, the patterns were less consistent.

Amongst all the HPV-positive cases, the commonest high-risk HPV genotypes were type 52 and type 16. HPV type 62 and type 81 represented the commonest low-risk HPV genotypes detected in the population studied. Infection by other HPV genotypes showed various patterns in different age groups.

Conclusions The overall prevalence of HPV infection in Hong Kong females correlates with age of the patients and corresponding cytologic diagnosis. Women younger than 25 years and older than 54 years are more likely to harbor HPV. The patterns of HPV infection in local patients can be useful in future preventive measures such as vaccination.