In 2019, The International Agency for Research on Cancer (IARC) launched the Cancer Screening in Five Continents (CanScreen5) project as a global cancer screening data repository that aims to report the status and performance of breast, cervical and colorectal cancer screening programmes using a harmonised set of criteria and indicators. Data collected mainly from the Ministry of Health in each country underwent quality validation and ultimately became publicly available through a web-based portal. Until September 2022, 84 participating countries reported data for breast, cervical or colorectal cancer screening programmes in the repository.
Substantial heterogeneity was observed regarding programme organisation and performance. Screening programme organisation was better overall in Europe compared to other continents; however, there were substantial gaps in implementation across both high- and low-resource settings. The findings are published by Partha Basu of IARC, Lyon, France and CanScreen5 collaborators on 27 April 2023 in the Nature Medicine.
A decline in cancer-specific mortality can be achieved through the implementation of screening programmes for specific cancers; such programmes need effective planning, adequate financial, human, and technical resources, and stringent quality control. Following the experiences of high-income countries (HICs), several low- and middle-income countries (LMICs) have included cancer screening programmes in their national cancer control plans. Many of such screening programmes, most being in LMICs and some even in HICs, have failed to deliver the expected clinical benefits.
One of the key factors contributing to the ineffective nature of these programmes is the absence of an information system to collect performance data across the screening continuum, from the identification of the target population to the treatment and follow-up of screen-detected cancers and precursor lesions and using the same for quality improvement of the programme. An organisation collecting individual-level data of the population offered cancer screening using an information system and using the same for programme management is known as a screening registry, the authors underlined in the background.
Many European Union (EU) Member States have remained at the forefront of implementing quality-assured, population-based cancer screening programmes with a strong policy commitment and adequate resource allocation. These programmes are guided mostly by evidence-based recommendations from European quality assurance guidelines in breast, cervical and colorectal cancer screening, which consistently highlight the necessity of regular monitoring and evaluation. To achieve this, a cancer screening registry is vital to collect, use and store cancer screening data at the individual level that underpins the entire continuum of cancer screening. A screening registry is also an essential tool to implement invitation-based screening and track screen-positive individuals to ensure their compliance to further management.
The IARC reported the status and the performance of cancer screening programmes from EU Member States in the years 2008 and 2017. Such consecutive evaluations permit comparisons in the performance of screening programmes using a harmonised set of indicators. Outside the EU, cancer screening evaluation reports have only been published regularly in a few countries. Most LMICs have only been reporting screening coverage based on population surveys because of logistic, fiscal and organisational challenges of data collection across the screening continuum. Validated data made publicly available through the CanScreen5 portal will support programme managers in cancer screening evaluation, benchmarking, quality improvement and informed policy formulation.
The report published in the Nature Medicine describes how the CanScreen5 project works and reports the status, organisation and performance of screening programmes that have participated in the project up to September 2022. A total of 84 countries from 5 continents have participated in the CanScreen5 project, including 17 countries from Africa, 27 from the Americas, 10 from Asia, 29 from Europe and 1 from Oceania (Australia). Among these countries, seven (Antigua and Barbuda, Bulgaria, Dominica, Ecuador, Libya, Saint Kitts and Nevis and Saint Lucia) were not included in the analysis because they did not fulfill the minimum criteria of having a screening programme for the cancer sites, they submitted information on.
Fifty-seven countries reported for breast cancer, 75 for cervical cancer and 51 for colorectal cancer screening programmes. Most of the countries (88.1%, n = 74) reported for national programmes, while others (Canada, China and India) reported only one or more regional programmes.
Substantial heterogeneity was observed regarding programme organisation and performance. Reported screening coverage ranged from 1.7% in Bangladesh to 85.5% in England, United Kingdom for breast cancer, from 2.1% in Côte d’Ivoire to 86.3% in Sweden for cervical cancer, and from 0.6% in Hungary to 64.5% in the Netherlands for colorectal cancer screening programmes.
Large variability was observed regarding compliance to further assessment of screening programmes and detection rates reported for precancers and cancers. A concern is lack of data to estimate performance indicators across the screening continuum. This underscores the need for programmes to incorporate quality assurance protocols supported by robust information systems. Programme organisation requires improvement in resource-limited settings, where screening is likely to be resource-stratified and tailored to country-specific situations.
The CanScreen5 project is a dynamic, ongoing activity and not just an one-time data collection project. The project team will continue with engagement with countries, especially LMICs, to enhance data collection and quality. Investments in information technology infrastructures, high population coverage with broadband and Internet facilities, and digital capability building of the health workforce to mitigate the COVID19 pandemic-induced health crisis have created an enabling environment for countries to strengthen multisectoral digital healthcare. The authors are optimistic that screening programmes will take advantage of this accelerated digital transformation to reform the process of data collection. This will in turn improve the quality of data in CanScreen5.
In an accompanied editorial article, Ni Li of the Office of Cancer Screening and Key Laboratory of Cancer Data Science, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital Chinese Academy of Medical Sciences and Peking Union Medical College in Beijing, China and colleagues wrote that in order to replicate the benefits observed with different screening approaches in controlled research studies, it is vital to achieve strict quality control through all screening pathways in a real-world service setting. The CanScreen5 project provides a tool for monitoring the performance and improving the quality of global cancer screening programmes and highlights the importance of robust quality assurance in this setting.
- Zhang L, Mosquera I, Lucas E, et al. & CanScreen5 collaborators. CanScreen5, a global repository for breast, cervical and colorectal cancer screening programs. Nature Medicine; Published online 27 April 2023. DOI: https://doi.org/10.1038/s41591-023-02315-6
- Wang F, Dong X, Li N. A call to improve the quality of screening programs. Nature Medicine; Published online 27 April 2023. DOI: https://doi.org/10.1038/s41591-023-02305-8