Cancer screening for breast, colorectal and cervical cancers underwent a significant reduction across the world during the COVID-19 pandemic
Cancer screening services for breast, colorectal and cervical cancers underwent a significant reduction during the early part of the COVID-19 pandemic compared to pre-pandemic levels according to the results of a systematic review by a group of Italian and US researchers.
GLOBOCAN data showed how in 2020 there were an estimated 19.3 million new cancer cases and almost 10.0 million cancer deaths. Moreover, other work has identified that cancer screening has contributed to a decrease in both cancer morbidity and mortality. Given the importance of screening, it is possible that any reduction could potentially lead to a surge in cases. While it will be several years before the full impact of reduced screening becomes apparent, modelling studies have already indicated a possibly large increase in cases due to the pandemic. For example, one Canadian simulation suggested that the interruption of services to COVID-19 could lead to an additional 310 cases diagnosed at advanced stages and 110 cancer deaths. Moreover, in a UK-based modelling study, the authors estimated that due to the pandemic, there would be a 7·9-9·6% increase in the number of deaths due to breast cancer up to year 5 after diagnosis and for colorectal cancer a 15·3 – 16·6% increase in additional deaths.
However, due to differences in the start date and duration of lockdown measures initiated during the pandemic, for the present study, the researchers wanted to examine how this variation impacted on screening in different parts of the world. They specifically focused on breast, colorectal and cervical cancer screening since the beginning of the pandemic and compared this with pre-pandemic levels. The team searched all the major databases for observational studies and articles that reported data from cancer registries and which made a comparison of screening tests performed before and during the pandemic in across the world.
Cancer screening reductions during the pandemic
A total of 39 articles were included in the analysis with 21 related to breast, 22 colorectal and 11 for cervical cancers.
For the period between January and October 2020, there was an overall 46.7% (95% CI -55.5% to -37.8%) decrease in breast cancer screening in comparison the pre-pandemic level.
For colorectal cancer, the overall reduction was 44.9% (95% CI -53.8% to -36.1%) and this included a 52.5% reduction in colonoscopy, a 37.8% decrease in faecal occult blood testing and a 37.8% decrease in immuno-chemical testing.
With cervical cancer, the overall reduction was -51.8% (95% CI -64.7% to -38.9%).
Commenting on their findings, the authors noted that while the reductions in screening were apparent across the world, there were some obvious differences. For example, Europe saw the largest reduction in mammography compared to North America, although the decrease for both colorectal and cervical cancer screening were similar in both areas. The authors suggested that the most likely explanation for the reduced screening was the ‘stay at home’ order introduced during the early stages of the pandemic.
They concluded that there was a large reduction in cancer screening as a consequence of the COVID-19 pandemic and which could be associated with an increased number of deaths and called for further work to investigate the relationship between cancer diagnosis and treatment during the pandemic.
Citation
Teglia F et al. Global Association of COVID-19 Pandemic Measures With Cancer Screening: A Systematic Review and Meta-analysis JAMA Oncol 2022
