Human papilloma virus (HPV) is a key factor in the development of cervical carcinoma. High-risk types of this virus are found in nearly all squamous-cell cervical cancers. HPV infection precedes cervical intraepithelial neoplasia (CIN), and is viewed as the most important factor in both premalignant cell changes and invasive cancer. HPV testing is highly sensitive for CIN lesions. The Pap smear is less sensitive but more specific. Many of the approximately 500 women in Sweden who are found each year to have cervical cancer have chosen not to be screened. A self-sampling device (SSD) for collecting vaginal smears now is available.
This study compared the results of three sampling methods in 43 women who previously had abnormal cervical cytology. The women collected vaginal samples by inserting the SSD into the bottom of the vagina and rotating it one turn. The upper part of the device then was inserted into a test tube and cut off. Samples were evaluated using the Hybrid Capture 2® (HC2) assay for high-risk HPV DNA. Samples collected by a clinician using a cytobrush and ordinary cytological samples also were acquired. The former were analyzed using a polymerase chain reaction (PCR) assay.
Carcinogenic types of HPV were detected in 37% of samples collected by women using the SSD. The PCR assay detected HPV DNA in 40% of samples; types 16, 18, and 33 were most prevalent. Agreement between the HC2 and PCR assays for detecting HPV DNA was 70%. Twelve of the 43 Pap smears demonstrated positive cytologic findings; 4 of them revealed CIN 2–3. Agreement between HC2 analysis and the Pap smear was 67%, and between the PCR assay and the Pap smear, 74%.
Regardless of what sampling method is used, testing for high-risk HPV is able to identify more women at risk of developing cervical cancer than conventional cytologic analysis. The SSD for collecting vaginal smear samples appears to be helpful in screening for cervical cancer in women who turn down an opportunity to be screened cytologically. This approach may be especially productive in women older than 35 years, who are likelier than younger women to present with persistent HPV infection.