Evaluation model of the Mexican national program for early cervical cancer detection and proposals for a new approach

An evaluation model on cervical cancer (CC) prevention in Mexico was carried out during 1990-95, using three observation units: women at risk, screening providers, and use of health services.

A diagnostic procedure of the pitfalls was applied to the following steps of the screening procedure: Pap sampling quality, cytological diagnosis validity, compliance of women, and determinants of nonparticipation.

The low effectiveness of screening for CC is due principally to factors associated with quality and coverage. Quality of Pap is deficient; 64 percent of a random sample of specimens lacked endocervical cells. Reading centers presented false negative indices between 10 and 54 percent. Women seek screening in a late stage of disease (55 percent with CC seek care because they have symptoms). In addition, coverage is low; in women between 15 and 49 years of age in Mexico City, 64.2 percent have a history of Pap smears, compared with 30 percent in rural areas. Knowledge of what the Pap is used for strongly determines use of screening. In rural areas, only 40 percent know the purpose of the Pap.

This information justifies an intervention to reorganize CC screening in Mexico, through strategies for improving compliance, quality, follow-up, and treatment for abnormal screens.