Background: The presence of cervical atypia on the Papanicolaou (Pap) smear may be an indicator of significant cervical disease. Many investigators recommend that colposcopy be performed in these women. We wished to determine the prevalence of undetected cervical intraepithelial neoplasia (CIN) among women identified as having cervical atypia by cytologic testing in a primary care setting.
Methods: Pap smears were performed on all women (N = 7458) attending six family practice offices for a health maintenance examination from August 1989 through February 1991. Cytologic specimens were obtained using an endocervical Cytobrush and wooden spatula. Consenting subjects with cervical atypia underwent repeat Pap smear testing immediately before a colposcopic examination after a 4- to 6-month waiting period.
Results: One hundred fifty-nine women identified as having cervical atypia consented to having a colposcopic examination. Of these, 96 (60%) demonstrated abnormalities on biopsy, including 40 with condyloma, 41 with CIN I, and 15 with CIN II to III. The false-negative rate of the follow-up Pap smear for detecting these cases of condyloma and CIN was 57%.
Conclusions: One third of the women with cervical atypia identified on an initial Pap smear in this primary care community setting had CIN after colposcopic biopsy. The single follow-up Pap smear obtained with the endocervical Cytobrush and wooden spatula failed to detect one half of the cases of biopsy-proven CIN. Further studies regarding the use of additional screening methods for follow-up are necessary.