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Objectives

This study aimed to assess the impact of the COVID-19 lockdown on the screening and diagnosis of breast, colorectal, lung, and prostate cancer. The study also investigated whether the rates returned to pre-pandemic levels by December 2021.

Design

Cohort study.

Setting

Electronic health records from UK primary care Clinical Practice Research Datalink (CPRD) GOLD database.

Participants

The study included individuals registered with CPRD GOLD between January 2017 and December 2021, with at least 365 days of prior observation.

Main outcome measures

The study focused on screening, diagnostic tests, referrals and diagnoses of first-ever breast, colorectal, lung, and prostate cancer. Incidence rates (IR) were stratified by age, sex and region, and incidence rate ratios (IRR) were calculated to compare rates during and after lockdown with the reference period before lockdown. Forecasted rates were estimated using negative binomial regression models.

Results

Among 5,191,650 eligible participants, the initial lockdown resulted in reduced screening and diagnostic tests for all cancers, which remained dramatically reduced across the whole observation period for almost all tests investigated. For cancer incidence rates, there were significant IRR reductions in breast (0.69), colorectal (0.74), and prostate (0.71) cancers. However, the reduction in lung cancer incidence (0.92) was non-significant. Extrapolating to the entire UK population, an estimated 18,000 breast, 13,000 colorectal, 10,000 lung, and 21,000 prostate cancer diagnoses were missed from March 2020 to December 2021.

Conclusion

The national COVID-19 lockdown in the UK had a substantial impact on cancer screening, diagnostic tests, referrals and diagnoses. Although incidence rates started to recover after the lockdown, they remained significantly lower than pre-pandemic levels for breast and prostate cancers and associated tests. Delays in diagnosis are likely to have adverse consequences on cancer stage, treatment initiation, mortality rates, and years of life lost. Urgent strategies are needed to identify undiagnosed cases and address the long-term implications of delayed diagnoses.

WHAT IS ALREADY KNOWN ON THIS TOPIC

• Breast, colorectal, lung, and prostate cancer are the most common causes of cancer death in the UK.

• The COVID-19 pandemic led to the postponement of cancer screening programs and reductions in diagnostic tests, resulting in delays in diagnosis and treatment initiation, impacting prognosis and mortality rates.

• Comprehensive data on the impact of changing social restrictions and post-lockdown periods is lacking in the UK, along with an assessment of specific screening pathways and patient experiences within the healthcare system.

WHAT THIS STUDY ADDS

• The first UK national COVID-19 lockdown resulted in reductions in screening, diagnostic tests, and referrals, particularly for mammograms, colonoscopies, and visits to breast surgeons, leading to underdiagnosis of breast, colorectal, and prostate cancers. Despite some increase in rates after the lockdown, they remained significantly lower than pre- pandemic levels by December 2021, particularly for prostate cancer.

• Most affected populations were women aged 60-79 years for breast and colorectal cancer; men aged 60-79 years for lung cancer; and men aged 40-59 years for prostate cancer.

• Delays in diagnosis are likely to have consequences on cancer stage at diagnosis, treatment initiation, mortality rates, and total years of life lost. Strategies such as public awareness campaigns, targeted screening programs, and improved coordination between primary care and hospitals are needed to address the backlog and identify the potential ∼62,000 missed cancer cases in the UK.