Cancer-Specific Changes in Diagnostic Activity During the COVID-19 Pandemic: An Analysis of Canadian CiNA Data

To analyze the patterns of change in diagnostic activity of different cancers before and after 2020, among Canadian jurisdictions covered in the CiNA dataset.

The Cancer in North America (CiNA) dataset was accessed, and crude rates of some of the most common cancers in Canada were reviewed (2010-2022). These included cancers of the breast, colorectum, cervical, prostate, melanoma of the skin, lung, and non-Hodgkin lymphoma. These cancers encompassed a variety of diagnostic pathways (organized screening, opportunistic early detection, and symptom-driven diagnoses). Descriptive drop rates (comparing 2020 rates to pre-2020 rates) and recovery rates (comparing 2021-2022 rates to pre-2020 rates) were calculated.

For the group of patients eligible for colorectal cancer screening in Canada (50-74 years old), the drop rate of 2020 (compared to pre-2020 baseline) was -20.9 and the recovery rate of 2021-2022 (compared to pre-2020 baseline) was -8.8. Likewise, for breast cancer and within the age group recommended for screening in most Canadian jurisdictions (50-74 years old), the drop rate (for 2020 compared to previous years) was -7.2, and the recovery rate for 2021-2022 (compared to pre-2020 baseline) was 1.96. Similar drop and recovery rates were observed for cancers diagnosed usually through opportunistic early detection (prostate cancer and melanoma of the skin). The same was not observed for lung cancer or non-Hodgkin lymphoma.

There was evidence of a non-uniform disruption of cancer diagnostic activity in 2020 in Canada (with breast and colorectal cancers showing a considerable disruption), which likely reflects the varying sensitivities of different diagnostic pathways to healthcare disruptions.