Whole-population trends in pathology-confirmed cancer incidence in Northern Ireland, Scotland and Wales during the SARS-CoV-2 pandemic: A retrospective observational study

INTRODUCTION: The COVID-19 epidemic interrupted normal cancer diagnosis procedures. Population-based cancer registries report incidence at least 18 months after it happens. Our goal was to make more timely estimates by using pathologically confirmed cancers (PDC) as a proxy for incidence. We compared the 2020 and 2021 PDC with the 2019 pre-pandemic baseline in Scotland, Wales, and Northern Ireland (NI). METHODS: Numbers of female breast (ICD-10 C50), lung (C33–34), colorectal (C18–20), gynaecological (C51–58), prostate (C61), head and neck (C00-C14, C30–32), upper gastro-intestinal (C15–16), urological (C64–68), malignant melanoma (C43), and non-melanoma skin (NMSC) (C44) cancers were counted. Multiple pairwise comparisons generated incidence rate ratios (IRR). RESULTS: Data were accessible within 5 months of the pathological diagnosis date. Between 2019 and 2020, the number of pathologically confirmed malignancies (excluding NMSC) decreased by 7315 (14.1 %). Scotland experienced early monthly declines of up to 64 % (colorectal cancers, April 2020 versus April 2019). Wales experienced the greatest overall change in 2020, but Northern Ireland experienced the quickest recovery. The pandemic's effects varied by cancer type, with no significant change in lung cancer diagnoses in Wales in 2020 (IRR 0.97 (95 % CI 0.90–1.05)), followed by an increase in 2021 (IRR 1.11 (1.03–1.20). CONCLUSION: PDC are useful in reporting cancer incidence quicker than cancer registrations. Temporal and geographical differences between participating countries mirrored differences in responses to the COVID-19 pandemic, indicating face validity and the potential for quick cancer diagnosis assessment. To verify their sensitivity and specificity against the gold standard of cancer registrations, however, additional research is required.