The COVID-19 pandemic affects mortality and morbidity, with disruptions expected to continue for some time,
with access to timely cancer-related services a concern. For breast cancer, early detection and treatment is key to
improved survival and longer-term quality of life. Health services generally have been strained and in many
settings with population breast mammography screening, efforts to diagnose and treat breast cancers earlier have
been paused or have had reduced capacity. The resulting delays to diagnosis and treatment may lead to more
intensive treatment requirements and, potentially, increased mortality. Modelled evaluations can support responses to the pandemic by estimating short- and long-term outcomes for various scenarios. Multiple calibrated
and validated models exist for breast cancer screening, and some have been applied in 2020 to estimate the
impact of breast screening disruptions and compare options for recovery, in a range of international settings. On
behalf of the Covid and Cancer Modelling Consortium (CCGMC) Working Group 2 (Breast Cancer), we summarize and provide examples of such in a range of settings internationally, and propose priorities for future
modelling exercises. International expert collaborations from the CCGMC Working Group 2 (Breast Cancer) will
conduct analyses and modelling studies needed to inform key stakeholders recovery efforts in order to mitigate
the impact of the pandemic on early diagnosis and treatment of breast cancer
