The fallacy of the screening interval for cervical smears.

One hundred seventy-four women with invasive cervical carcinoma were interviewed about their cervical smear histories to assess the accuracy of self-reporting and to relate the smear history with patient and tumor characteristics. Patients reported significantly more frequent, more recent, and more normal smears than were documented in medical records. The interval between onset of cancer symptoms and previous smear correlated directly with advanced stage. Sixteen women with normal smears within 36 months had significantly more advanced cancers than did 25 women with recent abnormal smears. Women with recent normal and abnormal smears had similar sociodemographic and behavioral characteristics. Because of inaccuracies in patients' self-reported smear histories and cancers developing in women with recent normal smears, we conclude that a specific screening interval should not be relied upon.