Impact of Widespread Cervical Cancer Screening: Number of Cancers Prevented and Changes in Race-specific Incidence.

Abstract

With recent approval of standalone HPV testing and increasing uptake of HPV vaccination, some have postulated that we are moving toward a "post-Pap" era of cervical cancer prevention. However, the total number cases that have been prevented by Pap smear screening as well as its impact on racial disparities are unknown. We estimated national cervical cancer incidence from 1976 to 2009 using the Surveillance, Epidemiology, and End Result database. Screening data were obtained from the literature and National Cancer Institute Progress Reports. We examined early, late, and race-specific trends in cancer incidence, and calculated the estimated number of cancers prevented over the past 3 decades. From 1976 to 2009, there was a significant decrease in the incidence of early-stage cervical cancer, from 9.8 to 4.9 cases per 100,000 women (P<0.001). Late-stage disease incidence also decreased, from 5.3 to 3.7 cases per 100,000 women (P<0.001). The incidence among black women decreased from 26.9 to 9.7 cases per 100,000 women (P<0.001), a greater decline compared with that of white women and women of other races. After adjusting for "prescreening era" rates of cervical cancer, we estimate that Pap smears were associated with a reduction of between 105,000 and 492,000 cases of cervical cancer over the past 3 decades in the United States. A large number of early-stage and late-stage cervical cancers were prevented and racial disparity in cancer rates were reduced during an era of widespread Pap smear screening.