Introduction

Cancer strongly compromises the health status of those affected and, in many cases, leads to death [1]. In 2019 in Chile, cancer ranked first among the non-transmissible chronic diseases causes of death, overtaking cardiovascular diseases [2]. Likewise, it can be noted that during 2018, 53 365 new cases of cancer, 28 443 deaths, and a prevalence of 135 618 patients were registered in Chile, this being only estimates "because no one knows exactly how many people have cancer, how many patients die from this cause or how many children and adults are diagnosed since there is no unified, updated, and detailed database." [3]. The lack of a National Cancer Registry in Chile means that information on the epidemiological situation is not available because, since such information is provided by population-based cancer registries [4], only five registries of this kind are available in the country. These are located in certain areas (Arica and Parinacota, Antofagasta, Maule, Los Ríos, and Bío Bío) [5], with significant differences between regions [4].

However, population-based cancer registries are recognized as a "valid and reliable methodology for the systematic collection of all cancer cases diagnosed within a population" [6]. In this sense, these registries are considered by the World Health Organization and its International Agency for Research on Cancer (IARC) as the epidemiological information system that should be the basis for morbidity surveillance of this health problem [4].

En este caso, a diferencia de los estudios clínicos o registros hospitalarios, donde los resultados se refieren a grupos particulares de pacientes, los registros poblacionales del cáncer aportan información sobre las tasas de incidencia, mortalidad y supervivencia del cáncer en todos los sujetos de una población [6]. Sin embargo, un desafío mayor a dichos registros es contar con un Registro Nacional del Cáncer, porque “es muy difícil efectuar análisis epidemiológicos y programáticos con total validez mientras no se cuente con información completa sobre la incidencia de cánceres relevantes con inclusión del sector privado y sobre las interacciones entre los servicios públicos de salud” [7]. Además, en los registros de cáncer se mide la supervivencia poblacional, cuyas tasas son los indicadores más directos de la gravedad del cáncer y del impacto del tratamiento, siendo un antecedente fundamental para promover políticas públicas [8]. Por ello, se trata de un gran desafío, porque un Registro Nacional del Cáncer no puede originarse a partir de una sola fuente y la información aportada debe ser precisa y actualizada e incluir otros elementos como el seguimiento de pacientes [7]. All this implies an enormous technological effort, in addition to achieving consensus among the multitude of actors involved, which makes the task complex. This article presents the design and development of the Chilean National Cancer Registry, the challenges faced, and its strengths and weaknesses.

Challenges for cancer surveillance in Chile

Advances aimed at improving the detection, care, and follow-up of people with cancer have gradually met certain milestones in Chile, the most recent being the National Cancer Plan in 2018 [8], which contemplates within its strategic lines the strengthening of registration, information and surveillance systems in order to have timely information that allows improving network management, conducting more cancer research, monitoring the development of the National Cancer Plan and making of decisions at the population level in cancer [8]; and subsequently the National Cancer Law (Law 21 258) [9], which stipulates that "cancer will be considered a notifiable disease. Consequently, the provisions of article 49° of the Health Code must be complied with". However, despite the existence of a mandate, the National Cancer Registry is not in use, and the information available in the population-based cancer registries at health authority sites shows figures severely outdated [5].

The National Cancer Registry [5] should be understood as an information matrix that gathers individuals with suspected, diagnosed, treated, and followed-up cancer for surveillance and data collection, thus contributing to scientific research, public health decision-making, and the healthcare of people suffering from the disease.

It was developed and tested with a successful pilot, in which more than 20 hospitals in the country participated, achieving a registry of nearly 7500 cases [10]. However, the National Cancer Registry was not implemented nationwide after its piloting. This tool will make it possible to know the real incidence of cancer in the country by systematizing the information on cancer patients in a technological platform with national coverage when all the establishments that provide these services report information. The National Cancer Registry is a public good developed together with the Ministry of Health with the support of the Production Development Corporation to support healthcare authorities with a national information system that serves to continuously and systematically collect, store, process, and analyze information on the cases and types of cancers occurring in the country, integrating public and private health patients [3]. The National Cancer Registry’s development resulted from a long and complex co-design and development process involving different relevant actors, including representatives of the national health authority, oncology, and epidemiology specialists. It results from years of research and technological innovation associated with the awarding of competitive funds.

Co-design of the National Cancer Registry

To design the National Cancer Registry, four stages in the care process and registry were defined: suspected diagnosis, morphological confirmation (biopsy), clinical resolution (indication for treatment), and oncological treatment and follow-up. The National Cancer Registry was developed in four phases. During Phase I (from 2018 to 2019), the first version (1.0) was achieved with the functional and non-functional characteristics outlined in the working tables. Following the piloting process, the next version (2.0) incorporated the missing aspects, including new variables, the recording events, the relevant actors, morphological confirmation, and clinical resolution. In this sense, the difference between the first and second versions was that the latter defined the system actors, the targeted groups, and the required tasks for each actor.

In phase II (year 2020), agreements were reached with the national health authority (Ministry of Health), achieving 100% acceptance of the agreed requirements in a fully functional version (2.4), which incorporated the pending aspects that were not addressed in phase I. All of the above under the current ethical and legal framework, following national and international standards, classifications, norms, and best practice guidelines [11].

In phase III (year 2020), the final version (2.4) was introduced on the Ministry of Health servers. In phase IV (year 2021), additional developments were carried out incorporating improvements and new requirements made by the Ministry of Health, generating a new version (2.7.0) available to collect data from existing national electronic clinical records at the primary, secondary, or tertiary care level. Regarding the above, registrable cases are defined by the technical standard No. 72 on population-based cancer registries of the Ministry of Health [1].

Thus, the platform for the National Cancer Registry aims to gather quality clinical information and generate knowledge from the systematic recording of variables related to the anatomopathological and clinical diagnosis of patients. Thus, the National Cancer Registry contemplates the corresponding training process for data providers, aiming to standardize the collection methodology and avoid biases. The information provided by the National Cancer Registry is presented below, according to the fields required for the registry, which have been separated into different tables for easier reading. Table 1 presents the data for patient identification and morphological conformation, and Table 2 the information on clinical resolution.

Final considerations

Creating the Chilean National Cancer Registry resulted from continuous discussions and agreements among various stakeholders. Its design contemplated the challenge of transversally integrating clinical, hospital, and population registries. Experts point out that a National Cancer Registry is necessary to achieve valid epidemiological and programmatic analyses [7]. However, its use in practice is subject to governmental decisions, and it is not currently active, even though the health authority states it is part of the National Cancer Plan [5]. Thus, among the barriers to using national cancer registries are the associated workload, the scarce recognition of their value by the authorities, the need for a commitment in the chain of reporting actors regarding the value of the aggregated individual information, and ethical and legal aspects [6].

The National Cancer Registry is a key technological tool for healthcare management and applying public health policies in the oncological field by collecting, storing, processing, and analyzing data on all cases and types of cancer in the country, including patients in the public and private sectors. In this sense, as a whole, the National Cancer Registry information contributes to establishing priorities in allocating resources and promoting research activities in specific areas [8]. This surveillance system is oriented to cancer monitoring, making it possible to observe patterns of this disease in different populations and to identify high-risk groups. A fundamental purpose of these tools is to support decision-making, guide actions in groups with specific needs, and be useful for planning and evaluating cancer control programs.