Pap smear screening and invasive cervical cancer.

Possible failures of Pap smear screening were assessed among 63 cases of invasive cervical cancer that occurred in a group practice population between 1965 and 1975. Review of medical records revealed 33 (53 percent) cases with no history of Pap smears within two years prior to diagnosis. Among the 30 patients with recent Pap screening, 11 (17 percent) had negative smears; these could only be explained as false negatives or unusually rapid progression of disease. The remaining 19 (30 percent) had abnormal smear results, a number of whom received suboptimal follow-up care. Similar experiences have been reported from several other health care settings. Implications for preventive practices are discussed.