Variation in the duration of protection given by screening using the Pap test for cervical cancer.

The duration of protection offered by Pap screening for cervical cancer was examined using data on 101 cases of invasive cervical cancer and 396 controls from a Maryland case-control study. Receipt of a Pap test up to 4 years ago afforded significant protection, compared to women screened 11 or more years ago, or never screened. Smoking, intercourse before age 19, and a history of sexually transmitted disease were significant risk factors for cervical cancer; barrier contraception use was protective. Variation in protection from Pap screening was examined by age, race, age at first intercourse, barrier contraception use, and source of last Pap test (obstetrician-gynecologist vs other provider type). Results showed older women, women with earlier age of first intercourse, and non-users of barrier contraception received slightly less protection from Pap tests, while women who received their last Pap test from an obstetrician-gynecologist received significantly more protection than women who did not. Issues of quality of screening and follow-up are discussed in regard to these results.