Decreasing cervical cancer mortality in Mexico: Effect of Papanicolaou coverage, birthrate and the importance of diagnostic validity of cytology

Background: The reduction in cervical cancer mortality in developed countries has been attributed to well-organized, population-based prevention and control programs that incorporate screening with the Papanicolaou (Pap) smear. In Mexico, there has been a decrease in cervical cancer mortality, but it is unclear what factors have prompted this reduction. Methods: Using data from national indicators, we determined the correlation between cervical cancer mortality rates and Pap coverage, birthrate, and gross national product, using a linear regression model. We determined relative risk of dying of cervical cancer according to place of residence (rural/urban, region) using a Poisson model. We also estimated Pap smear coverage using national survey data and evaluated the validity and reproducibility of Pap smear diagnosis. Results: An increase in Pap coverage (beta = -0.069) and a decrease in birthrate (beta = 0.054) correlate with decreasing cervical cancer mortality in Mexico. Self-reported Pap smear rates in the last 12 months vary from 27.4% to 48.1%. Women who live in the central (relative risk, 1.04) and especially the southern (relative risk, 1.47) parts of Mexico have a greater relative risk of dying of cervical cancer than those who live in the north. There is a high incidence of false negatives in cervical cytology laboratories in Mexico; the percentage of false negatives varies from 3.33% to 53.13%. Conclusions: The decrease in cervical cancer mortality observed in Mexico is proportional to increasing Pap coverage and decreasing birthrate. Accreditation of cervical cytology laboratories is needed to improve diagnostic precision.