Background and purpose: The COVID-19 pandemic impacted substantially on cancer healthcare, including the temporary suspension of screening activities. We compared cancer incidence rates and stage during 2020-2021 to pre-pandemic rates in the Nordic countries.

Material and methods: Using data from the national cancer registries in Denmark, Finland, Iceland, Norway, and Sweden, we estimated age-, sex-, and period-adjusted incidence rate ratios, expressed as relative percentage change (%) with 95% confidence intervals (CIs), comparing rates in 2020-2021 to those in 2017-2019 (pre-pandemic).

Results: In 2020-2021, 340,675 cancer cases were diagnosed. The incidence rates declined during the first pandemic wave (Q2 2020), ranging from -21.7% [95% CI: -23.3%; -20.2%] (Sweden) to -7.9% [-17.7%; 3.0%] (Iceland). Incidence rates also declined in the second pandemic wave (Q1 2021), ranging from -8.6% [-10.2%; -6.9%] (Sweden) to -2.3% [-4.6%; 0.1%] (Norway), and in Sweden also by -3.1% [-4.8%; -1.3%] in the third pandemic wave (Q4 2021). Stage I breast cancer incidence declined during 2020 in Denmark/ Norway/Sweden, with some catch-up in stage II incidence in 2021. Prostate cancer rates declined in Denmark/Finland/Norway/Sweden during 2020-2021, while melanoma rates declined in Finland in 2020. During 2020, colon cancer rates declined in Denmark and Iceland, while rectal cancer rates declined in Denmark, and lung and kidney cancer rates declined in Norway.

Interpretation: During 2020-2021, cancer incidence rates declined across the Nordic countries with the largest declines in Sweden. During the third pandemic wave, the incidence rates were mostly similar to pre-pandemic rates. Changes in cancer stage may reflect reduced screening activities.