The impact of the COVID-19 pandemic on cancer incidence, stage distribution and survival in Switzerland: a register-based cohort study.

Background: The COVID-19 pandemic disrupted healthcare systems worldwide. This raised concerns about delays in cancer diagnosis and treatment, with potentially worse patient outcomes. The aim of this nationwide, population-based cohort study was to investigate the impact of the COVID-19 pandemic on cancer incidence, stage distribution and one-year survival in Switzerland.

Methods: We used national cancer registry data for the period 2017-2021 from the National Agency for Cancer Registration in Switzerland, covering all except three cantons. We estimated national cancer incidence counts and calculated age-standardised incidence rates for all cancers and separately for female breast cancer, colorectal cancer, lung cancer, melanoma and prostate cancer. We calculated proportional stage distributions for cancer types and estimated observed and relative one-year survival for all cancers and cancer types based on Swiss population life tables. Results were analysed descriptively.

Results: We included 218,736 cancer cases diagnosed between 2017 and 2021. Annual incidence counts of all cancer cases increased in 2020 (2.1%) and 2021 (7.3%) compared to the mean of 2017-2019. When evaluating monthly incidence counts, we observed a substantial decrease during the COVID-19 lockdown period, which was largest in April 2020 (-19.9% for all cancers). This decrease was most pronounced for female breast cancer (-39.9%), followed by prostate cancer (-29.0%), colorectal cancer (-28.7%) and melanoma (-26.9%). An increase in incidence counts for all cancers was observed in March 2021 (18.8%). We observed no clear shift in stage distributions across 2017-2021. The observed and relative one-year survival for all cancers and individual cancer types was similar in 2020 and slightly higher in 2021 compared to 2017-2019.

Conclusions: This nationwide study suggests that the pandemic had no major effect on short-term cancer patient outcomes. These findings are of importance for policymakers and the public health system regarding future pandemics.