According to GLOBOCAN estimates, 19.3 million new cancer cases and 10 million cancer deaths occurred in 2020 due to breast, colorectal, and cervical cancer, the first, third, and seventh-most prevalent cancers worldwide.
Cancer screening programmes help detect cancer at early stages and can lead to decreased mortality. In the past few years, cancer screening and prevention protocols have had a significant impact on public health, especially in low to middle-income countries. However, natural disasters and epidemics can negatively affect cancer screening rates and access to health care infrastructures and facilities, thus increasing the burden of cancer.
During the COVID-19 pandemic, many non-urgent medical services were suspended. These include family planning and abortion, HIV prevention, testing, and care, cancer prevention, delays or deferrals in oncologic surgery, systemic therapy and radiotherapy, and visits for oncologic patients. Cancer screening programmes were also temporarily interrupted in many countries.
In a systematic review of studies that analysed the variation in the total number of examinations for breast, cervical, and colorectal cancer screening performed since the beginning of the pandemic in comparison with the pre-pandemic period, researchers aimed to quantify the global variation of cancer screening procedures during the lockdown period. The main outcome of the review was the weighted average percentage variation in the number of screening tests performed between January and October 2020 compared with the previous period.
The review included 39 publications. Findings show that from January to October 2020, there was a significant decrease in different types of cancer screening, including a 46.7% decrease in breast cancer screening, a 44.9% decrease in colorectal cancer screening and a 51.8% decrease in cervical cancer screening.
The decrease has a U-shaped trend with a negative peak in April 2020, with a 74.3% decline in mammography screening and a 69.3% decline in colonoscopy fecal occult blood test or fecal immunochemical test.
This reduction in cancer screening was possibly associated with a delayed diagnosis and increased cancer mortality. These findings highlight the need for effective interventions to restore the capacity of screening services to pre-pandemic levels.
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