Prevalence of high-risk human papillomavirus (HR-HPV) types 16 and 18 in healthy women with cytologically negative Pap smear

Abstract

Objective: To study the prevalence of high-risk human papillomavirus (HR-HPV) types 16 and 18 in healthy women with negative Pap smears in identifying women with underlying cervical squamous intra-epithelial (SIL) lesions. Methods: A total of 3300 women who were attending the Gynecology OPD of Lok Nayak Hospital, one of the major government tertiary hospitals in New Delhi, were screened during a 1-year study period, and 2079 (63%) of them were found to have cytologically negative Pap smear with inflammation and the rest (37%) also had negative Pap report but without inflammation. Hundred and sixty of these sexually active women aged between 20 and 60 years were randomly selected, and were investigated by colposcopy and a guided biopsy was done wherever required. HPV types 16 and 18 DNA was detected in scraped cervical cells from all women using type-specific primers in polymerase chain reaction (PCR). Results: The high-risk HPV (type 16 and 18) prevalence by PCR was found to be 10% (16/160). Histopathological findings were obtained in 123 women, out of which 15 had LSIL and four had HSIL. High-risk HPV types 16/18 could be detected in nine out of these 19 (47.3%) squamous intra-epithelial lesions (p<0.00008) which includes two out of the four women (50%) having HSIL, while only seven out of 104 (6.7%) of the subjects with normal (negative) Pap reports (p=0.03) had infection of high-risk HPV. Conclusion: The results indicate that about 10% of women who show a negative Pap smear, but have inflammation are positive for high-risk HPV types 16/18 and about 15% harbor squamous intra-epithelial lesions. It is suggested that high-risk HPV detection can be utilized as an adjunct to routine cytology screening programs to identify 'high risk' women who have concurrently negative Pap smears but may harbor oncogenic HPV infection and/or more likely to develop CIN lesions.