Virologic screening

Advances in cervical screening technology

The Pap smear unquestionably is a successful screening test for cervical cancer. However, recent advances in technology have raised questions regarding whether the conventional Pap smear is still the standard of care. This article relates issues of screening and cost-effectiveness to the state of the art in thin layer preparations, cytology automation, human papillomavirus screening, human papillomavirus vaccines, and other cervical screening adjuncts. Perhaps nowhere in medicine is clinical decision making being more strongly influenced by market and other external forces than in cervical cytopathology.

Human papillomaviruses and cervical neoplasia: a model for carcinogenesis

Human papillomaviruses are etiologic for cervical cancers and their pathologic precursors. As presented in this review, pathologic, epidemiologic, and molecular data all support a working model that accounts for the pathogenetic role of these viruses in cervical neoplasia. Diagnostic criteria and classification systems are discussed in light of this model. These insights point to a potential change in clinical screening systems for cervical cancer. In addition, vaccine trials for oncogenic HPVs have begun. In the long term, these trials may hold promise as truly specific preventive therapy for this common human cancer.

Cervical cancer screening in developing countries: why is it ineffective? The case of Mexico

BACKGROUND

Mexico established a national cervical cancer-screening program in 1974. Despite the implementation of the program, there was a steady mortality trend of 16 per 100,000 women over 15 years.

METHODS

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 non-participation.

RESULTS

The low effectiveness of screening on cervical cancer is principally due to factors associated with quality and coverage. Pap quality is deficient; 64% of a random sample of specimens lacked endocervical cells. Reading centers presented false negative indices of between 10 and 54%. Women seek screening in a late stage of disease (55% with cervical cancer 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% have a history of Pap, compared with 30% in rural areas. Knowledge of what the Pap is used for strongly determines the use of screening. In rural areas, only 40% of women are informed about the purpose of the Pap test.

CONCLUSIONS

A proposal to reorganize Mexico's screening program includes the following five main strategies: (a) increased coverage; (b) improved quality control of how cervical smears are taken; (c) better interpretation of Pap tests; (d) guaranteed treatment for those whose tests show abnormalities, and (e) improved follow-up.