In 2021, the Section of Infections and the Section of Early Detection and Prevention were merged to form the Early Detection, Prevention, and Infections Branch (EPR).
The activities of EPR include a wide portfolio of study designs, including etiology and natural history, assessing the global burden, and evaluating and modelling the impact of interventions. A major theme is evaluating interventions through the lens of implementation science. Carcinogenic infectious agents are particularly amenable to cancer prevention (e.g. vaccines, diagnostic tools, and therapies), and the burden of infection-attributable cancers is disproportionately high in low- and middle-income countries (LMICs) (> 25% of all cancer cases in certain global regions). Therefore, a significant proportion of EPR’s prevention research focuses on infection-related cancers. EPR also supports capacity-building to implement quality-assured programmes for cancer prevention and early detection.
- To transform knowledge about established cancer causes and mechanisms, with a focus on carcinogenic infections, into evidence-based interventions that can prevent cancer suffering and death.
- To evaluate strategies for cancer prevention and early detection, with a view to reducing the cancer burden and improving survival and quality of life of patients after treatment.
- To support capacity-building and assess interventions in real health-care settings.
Major approaches/areas of activity
The interventions evaluated can be broadly categorized into those relevant to: (i) primary prevention of established modifiable infectious risk factors (e.g. preventing human papillomavirus [HPV] and hepatitis B virus [HBV] infection through vaccination; testing and treatment of Helicobacter pylori and hepatitis C virus [HCV]); (ii) screening of asymptomatic at-risk populations, for cancer sites for which the current evidence base is more established (cervical cancer, breast cancer, colorectal cancer) or experimental (e.g. gastric cancer, anal cancer, oral cancer, lung cancer); and (iii) early diagnosis of common cancer types in symptomatic individuals, with a view to shifting the stage distribution of tumours detected towards a lower stage, and improving survival and quality of life of patients after treatment. The evaluation of prevention, screening, and early diagnosis focuses on the effectiveness in real health-care settings and on understanding the related implementation challenges.
Primary prevention of carcinogenic infections
IARC is the global reference for estimates of the burden of infection-attributable cancer. This programme serves to raise awareness, inform recommendations for preventive action, prioritize resources, and monitor the long-term impact of cancer prevention policies that target infectious agents, on both the local and global scales. Current EPR priorities to improve these estimates include establishing the population attributable burden of HIV to cancer (e.g. cervical cancer, Kaposi sarcoma, non-Hodgkin lymphoma, anal cancer) and of Epstein–Barr virus to non-Hodgkin lymphoma and gastric carcinoma.
HPV vaccination is the main component of the World Health Organization (WHO) global strategy to eliminate cervical cancer as a public health problem, but it has had only limited roll-out in LMICs to date. EPR is engaged in evaluating the efficacy and effectiveness of, as well as modelling the impact of, HPV vaccination in different implementation scenarios, most notably that of a single dose of HPV vaccine. The evidence will guide health policies and support national authorities in implementing HPV vaccination programmes, particularly in LMICs, in order to reduce global disparities in cervical cancer. Similarly, EPR and WHO are collaborating to monitor the impact of the WHO target for elimination of viral hepatitis on the burden of liver cancer.
H. pylori is the most important infectious cause of cancer worldwide. In anticipation of results from ongoing research (the HELPER trial), which is expected to establish the efficacy of testing and treatment of H. pylori in reducing gastric cancer incidence, EPR is expanding research into the implementation of such programmes in LMICs, both by undertaking operational research in programmatic settings in LMICs and by leveraging expertise in modelling the natural history of carcinogenic infections.
Screening of asymptomatic at-risk populations
EPR is conducting a range of studies that evaluate new technological inventions in cancer screening and management of premalignant conditions and assess their suitability and applicability for implementation, in particular in limited-resource settings.
To accelerate the introduction of HPV-based screening, in alignment with the WHO Cervical Cancer Elimination Initiative, the IARC portfolio on cervical cancer screening includes: evaluation of novel HPV detection tests (detection of high-risk HPV E6/E7 oncoproteins, detection in urine using infrared spectroscopy); techniques for triage of HPV-positive women (e.g. the ESTAMPA study in Latin America); artificial intelligence for pattern recognition to detect cervical precancer; HPV screen-and-treat programmes in Africa, with a particular focus on women living with HIV; and a randomized controlled trial in Zambia on the efficacy, safety, and cost–effectiveness of cervical thermal ablation.
Continued follow-up of a randomized controlled trial to evaluate clinical breast examination for breast cancer screening in India will generate valuable evidence on the efficacy of this test. EPR is a collaborator in a study that combines H. pylori eradication with endoscopic surveillance to reduce gastric cancer mortality (the GISTAR study).
EPR is also conducting a range of studies to understand the major barriers to accessing quality-assured cancer screening, and to evaluate interventions directed at multiple levels (systems, providers, and clients) to increase participation. The Cancer Screening in Five Continents (CanScreen5) project evaluates the coverage and quality of cancer screening programmes globally. Implementation research studies aim to document the challenges that countries face while introducing major changes in their existing screening programmes (e.g. transitioning from cytology-based to HPV-based cervical cancer screening).
Early diagnosis of common cancer types
To better understand the challenges in implementing cancer early diagnosis and the means to improve it, in particular in LMICs, EPR is evaluating barriers to accessing timely diagnosis and treatment for symptomatic individuals, including measuring delays (access, systems, and treatment) across the cancer care pathway, and identifying setting-appropriate solutions to minimize such barriers and delays.
EPR is conducting studies that identify relevant gaps in the health systems across the cancer care continuum and suggest contextualized and sustainable solutions. Keeping pace with the advancement of technology, EPR is assessing the applicability of new technology: mobile technology to educate the community, the use of mobile phone-based applications for patient navigation, and the web-based promotion of telepathology and distance learning for service providers.
Furthermore, through collaboration with ministries of health in several countries (priorities for LMICs), EPR assists them in planning and implementing quality-assured cancer control programmes, including training of health professionals and researchers in the field of cancer prevention.