Influence of age and human papillomavirus-infection on reliability of cervical cytopathology.

The aim of the present study was to evaluate the effect of age and human papillomavirus (HPV) infection associated cellular changes on the predictive value of cervical cytology. In a group of 671 women with Papanicolaou smears suggesting low grade squamous intraepithelial lesion (LSIL), a high grade squamous intraepithelial lesion (HSIL) or invasive cervical cancer, cervical cytology was correlated with the histological finding. Predictive values were calculated and related to severity of the lesion, age and HPV associated changes. The predictive values of Papanicolaou (cervical) smears suggesting LSIL, HSIL and invasive carcinoma were 40%, 86%, and 78%, respectively. A poor predictive value of smears suggesting LSIL was found among older women. HPV associated changes were diagnosed in 80% of women < or = 25 years of age, 66% in the age group 26 to 35 years, 51% in the age group 36 to 45 years and 38% in women aged > or = 46 years (P = 0.03). The presence of HPV associated cellular changes led to a significantly higher number of overdiagnoses (9% with HPV infection compared to 4% without HPV infection) and HPV negative cases were more frequently associated with underdiagnosis (15% without HPV infection compared to 8% with HPV infection, P = 0.0011). This result remained significant after adjustment for age (P = 0.004). Cellular changes associated with HPV infection most frequently occurred in young women. HPV infection should therefore be acknowledged as source of overdiagnosis in the cytological evaluation of SIL especially in young women.