Impact of COVID-19 on 2021 cancer incidence rates and potential rebound from 2020 decline

Abstract

The COVID-19 pandemic led to substantial declines in cancer incidence rates in 2020, likely because of disruptions in screening and diagnostic services. This study aimed to assess the impact of the pandemic on cancer incidence rates in the United States using 2021 incidence data from the Surveillance, Epidemiology, and End Results program. The analysis compared observed 2021 cancer incidence rates with expected prepandemic trends, evaluating changes by individual cancer site and stage. Although incidence overall and in many cancer sites the rates were close to prepandemic levels, they did not exhibit a recovery that incorporated the delayed diagnoses from 2020. There were exceptions, however, such as metastatic breast cancer, which showed significantly higher observed rates than expected (rate ratio = 1.09, 95% confidence interval = 1.04 to 1.13). Ongoing monitoring and targeted interventions are needed to address the long-term consequences of the COVID-19 pandemic on cancer care and outcomes.

Figure 1.

Observed and modeled cancer incidence trends during the prepandemic period (2000-2019), projected incidence trends in 2020 and 2021 in the absence of the pandemic, and pandemic-affected 2020 and 2021 observed incidence rates by selected cancer types and stage at diagnosis. SEER-22, 2000-2021. SEER = Surveillance, Epidemiology, and End Results. Results for age-adjusted incidence rates are shown for all cancers combined (panel A) and 5 cancer sites: female breast cancer (panel B), prostate cancer (panel C), lung and bronchus cancer (panel D), pancreatic cancer (panel E), and thyroid cancer (panel E). We also show stage-specific, age-adjusted rates for breast cancer and thyroid cancer: female breast cancer, localized (panel G); female breast cancer, regional (panel H); female breast cancer, distant (panel I); thyroid cancer, localized (panel J); thyroid cancer, regional (panel K); and thyroid cancer, distant (panel L). Note that stage-specific rates are available from 2004 on, whereas overall rates for the 5 cancer sites are available from 2000 on. For each panel, we show age-adjusted incidence rates in blue (observed rates as squares, modeled rates as lines). The line segments of each curve were selected using the Joinpoint program, and a new joinpoint is detected when the line segments change. The dashed red lines are projected trends in 2020 and 2021 in the absence of the pandemic. Using the Joinpoint model’s parameters (ie, estimated intercept and slope from the last segment), we projected the expected trends in 2020 and 2021 in the absence of the pandemic.