What is the Natural History of Cervical Neoplasms Study?
The Natural History of Cervical Neoplasms Study is a randomized clinical trial of cases and controls, which began in September 1992, under the execution of the Guanacaste Epidemiological Project (PEC), currently the Costa Rican Agency for Biomedical Research (ACIB). This study included 12,000 women over 18 years of age and residents of districts in the province of Guanacaste, Costa Rica. Its objective was to provide scientific evidence through the analysis of lesions in the cervix.
Natural History of Cervical Neoplasms Study, means:
Population of the natural history of cervical neoplasms study in a high-risk region of Latin America (1992).
Importance of the Natural History of Cervical Neoplasms Study
During the 90’s, the epidemiological evidence that cervical cancer and its precursor lesions behaved as sexually transmitted diseases (Brinton and Fraumeni, 1986), motivated multiple researchers for more than 20 years, to search for the agent biological transmissible and responsible for the etiology of this disease.
By 1993, various epidemiological and molecular biology studies had shown the existence of a relationship between HPV infections and the arrest of cervical neoplasms (Kaufman, 1989).
The natural history of precancerous lesions in the cervix relate the beginning of infection to HPV, which very often presents without clinical or histological manifestations.
To carry out the Natural History of Cervical Neoplasms Study, Costa Rica represented a special opportunity, for various reasons, among them the main ones were:
- It was a region with a high incidence of cervical cancer, and with areas of especially high incidence, such as the provinces of Guanacaste and Limón. (Sierra et al, 1988).
- The existence of a National Health System with an excellent infrastructure and the operation of Costa Rican population registries, as well as a high educational level, dimensions of the national territory, road network and telecommunications; that facilitate the performance of epidemiological studies at the population level.
- The epidemiology of cervical cancer in Costa Rica has been extensively studied.
Objective of the Natural History of Cervical Neoplasms Study
The main objective of this research study was to analyze the natural history of cervical neoplasia in high-risk populations, with emphasis on the role of the human papillomavirus (HPV) and other possible cofactors.
Design Natural History of Cervical Neoplasms Study
The study consisted in the invitation to participate of 12,000 women chosen at random from the population of women over 18 years of age living in the Province of Guanacaste, considered at that time as a region with a high risk of cervical cancer.
The participants in this study formed two groups, that of women with the presence of precancerous or malignant lesions of the cervix and that of women with the absence of these lesions or without pathology, who constituted the follow-up cohort in which the determining factors were analyzed of the appearance of preneoplastic lesions.
The research consisted of two phases, in the first phase the invitation to participate and inclusion or recruitment was carried out, during the first 18 months, and during the second phase the follow-up was carried out, which began simultaneously and would continue for 5 years.
Principal investigator of the Natural History of Cervical Neoplasms Study: Dr. Mario Pacheco Mena, Director at that time of CENDEISSS.
Sponsor: National Cancer Institute of the United States (NCI).
Instituciones participantes del del Estudio Historia Natural de Neoplasias Cervicales: Instituto Nacional del Cáncer de los Estados Unidos (NCI); Ministerio de Salud de Costa Rica; Centro de Desarrollo Estratégico e Información en Salud y Seguridad Social (CENDEISSS) de la CCSS.
Aprobado por Comité Ético Científico.
