COVID-19 and Cancer Global Modelling Consortium (CCGMC): A global reference to inform national recovery strategies

As of March 2022, 2 years since the beginning of the novel coronavirus outbreak, a total of 6 million deaths due to COVID-19 have been reported across the world [1]. Early in the pandemic, concerns were raised that people with cancer who become infected with SARS-CoV-2, the virus that causes COVID-19, would be more likely to have severe COVID-19 complications and poor outcomes, compared with people without cancer [2]. The pandemic also exacerbated existing challenges in hospitals and health systems in the delivery of services across the cancer continuum, from prevention to palliative care [3]. Moreover, the implementation of non-pharmaceutical intervention (NPI) strategies to reduce exposure to and transmission of the SARS-CoV virus such as ‘lockdowns’ and social distancing, has resulted in changes in exposure to major cancer risk factors [4], such as smoking, alcohol consumption, dietary patterns and activity levels, which will impact the future burden of cancer.

Responding to the international need to provide evidence on the impact of disruptions and their mitigation, the COVID-19 and Cancer Global Modelling Consortium (CCGMC) was established in May 2020. The CCGMC aims to synthesise relevant evidence on COVID-19 and cancer and configure modelling platforms that inform decision-making in cancer control [5]. The CCGMC has developed three interrelated work streams, quantifying the impact of COVID-19 on cancer outcomes, screening and diagnosis, and cancer risk. The emphasis is on developing infrastructure that will allow dissemination of continuously updated short- and long-term projections of cancer-relevant outcomes. There is a major focus on evaluating potential prioritisation and recovery strategies during and following the severe social and health services disruptions experienced worldwide.

The first working group in CCGMC seeks to estimate the impact on cancer outcomes either through direct impact of the infection on death or other health outcomes in patients with cancer, delays in diagnosis following symptomatic presentation, or through disruption of cancer treatment services. Early reports suggested that cancer patients were at higher risk of COVID-19-related death compared to people without cancer; lung and haematological cancers have been of particular concern as have immunosuppressed patients [2]. To account for this in modelled outcomes, the CCGMC are conducting systematic reviews to identify the risk (if any) after accounting for all confounding and sampling issues. As estimates of the impact emerge, they will be progressively incorporated into modelled inputs, as will the potential modulating impact of COVID-19 vaccination on outcomes in cancer patients. During the first peak of the COVID-19 pandemic, disruptions to guidelines-based approaches to cancer management were reported in multiple settings. In the United Kingdom (UK), a 20% reduction in course of radiotherapy to cancer patients was reported [6], alongside protocol changes to all three modalities, i.e. surgical, systemic, and radiotherapy for certain cancer types [7]. Such delays can be critical. As the pandemic recedes, cancer diagnosis and treatment capacity will need to be temporarily expanded to mitigate the impact on cancer outcomes.

The second CCGMC work stream is focusing on estimating the impact of screening program disruptions on excess cancer deaths, using existing, well calibrated and validated model platforms. There have been extensive disruptions in high income countries [8], and a study of 20 low- and middle-income countries (LMICs) reported suspension of screening activities as well as disruption in diagnostic centres after the first round of national NPIs [9]. The CCGMC collaborators have predicted that even a three-month disruption in colorectal cancer screening would result in 324–440, 980 and 800 additional deaths in the Netherlands, Australia, and Canada, respectively, although this could be largely mitigated if missed screens are quickly caught up after the disruption [10]. Building on this work, studies assessing a range of mitigation strategies for colorectal, breast and cervical cancer screening are ongoing – considering simple as well as more novel approaches for risk stratification.

Finally, national NPI actions aiming to control the pandemic may also have unintended effects on behaviours associated with cancer risk. Data suggest these effects may be dynamic and heterogenous, with smoking exposure decreasing in some (but not all) groups [4], [11], a potential increase in binge drinking [4], a decline in physical activity [12], and an average increase in body weight during the first wave lockdowns [13]. Thus, the third working group of the CCGMC is conducting systematic reviews of behaviours associated with cancer risks during and after the pandemic. This seeks to inform modelling of the consequent long-term impacts on cancer risk, and the effects of cancer prevention strategies.

There is an urgent need to develop well validated models that harness data from studies that use representative populations, standard data collection methods and tools to evaluate the direct and indirect impact of the COVID-19 on short- and long-term cancer burden. Population-based cancer registry operations were also impacted by COVID-19, especially those in LMICs [14]; minimising this impact is a key element to achieving high quality estimates. An in-depth understanding of the impact of the COVID-19 pandemic relevant to cancer prevention and control, when possible including the role vaccination against COVID-19 vaccines, is essential to inform evidence-based policies that serve to minimise the effect on cancer health system disruptions. Estimation of the COVID-19 pandemic’s effect(s) on existing social inequalities is an important cross-cutting theme across the three CCGMC work streams. As a global research collaboration, the CCMGC is currently configuring a global COVID-19 and cancer ‘observatory’ which will provide policy decision-makers and other stakeholders with a continuously updated reference point for the most accurate evidence on cancer outcomes and optimal mitigation strategies. This, we hope, will inform national strategies relevant to cancer risk and outcomes and will support clinical decision-making going forward.

Competing interests

Prof Karen Canfell reports she is co-PI of an investigator-initiated trial of cervical screening, "Compass", run by the VCS Foundation Australia, which is a government-funded not-for-profit charity. The VCS Foundation has received equipment and a funding contribution from Roche Molecular Diagnostics. She is also co-PI on a major implementation program "Elimination of Cervical Cancer in the Western Pacific" which will receive support from the Minderoo Foundation and the Frazer Family Foundation and equipment donations from Cepheid Inc. However, neither KC nor her institution has received direct funding from industry for these or any other research project.

Other authors declare no conflict of interest.