Monitoring cancer survival in Belgium: early insights 3 years after the COVID-19 pandemic.

PURPOSE: In 2020, health care systems worldwide were challenged by the COVID-19 pandemic, disrupting the medical care trajectory of cancer patients. The observed diagnostic delays requested further monitoring including an assessment of survival probabilities.

METHODS

The 1-, 2- and 3-years relative survival (RS; Ederer II; follow-up until 1st May 2025) was calculated for invasive tumours diagnosed between 2017 and 2021 in Belgium (overall and per cancer type) and compared with asymptotic two-sided Z-tests on the log-transformed scale.

RESULTS

Following a decrease of the 1- and 2-years RS for 2020 (82.0% and 75.5%) compared to 2019 (82.5% and 76.1%), the 3-years RS for 2020 (72.0%) aligned again with the 3-years RS for 2019 (72.2%). The 2021 (1-, 2- and 3-years) RS and 2022 (1- and 2-years) RS estimates are in line with the increasing pre-pandemic survival rates for all cancers. The RS results showed a wide heterogeneity across cancer types. In addition, we observed small shifts in the characteristics of the cancer patient populations with contrasting impact on survival.

CONCLUSION

Since the start of the COVID-19 pandemic, the importance of timeliness in the monitoring of cancer incidence and survival emerged for many cancer registries worldwide. Based on our RS results, we advocate for tailored survival analyses per subpopulation (age group, cancer type, stage, etc.) to reveal mid- and long-term survival effects of the pandemic.