Impact of the COVID-19 pandemic on cancer incidence, stage, mortality, and short-term survival in Ireland: a population-based analysis

Background Concern exists that disruptions to health services in combination with changed health-seeking behaviour as a consequence of the coronavirus disease (COVID-19) pandemic would negatively impact cancer outcomes. The purpose of this study was to assess how the COVID-19 pandemic affected cancer incidence, stage at diagnosis, mortality, and 1-year net survival in Ireland. Materials and methods Age-standardised incidence and mortality rates were generated for three periods (2018-2019, 2020-2021, and 2022). Quarterly age-standardised incidence rates, incidence rate ratios (IRRs), and percentage change (PC) by cancer site were generated for Q1 2020 to Q4 2021. Annual incidence rates, IRRs and PC by stage at diagnosis were estimated. Age- and stage-adjusted 1-year net survival was estimated using the Pohar–Perme method. Results The age-standardised quarterly incidence rate of all invasive cancers (excluding nonmelanoma skin cancer) decreased significantly in Q2 2020, by 27% (95% CI −42% to −7%, P = 0.01), compared with 2018-2019. Decreases in the incidence of early-stage cancers (stages I or II) were seen in 2020, particularly for cancers in which organised or opportunistic screening occurs. There was little evidence of consistent increases in the incidence rate of stage III or IV cancers in 2021 or 2022. Age- and stage-adjusted 1-year net survival for all cancer sites in 2020-2021 remained in line with previous years. Conclusions The COVID-19 pandemic significantly disrupted cancer detection and diagnostic activity in Ireland during 2020. The early overall picture suggests that the resilience and adaptability of the Irish health care system helped to safeguard cancer outcomes during an unprecedented public health crisis.