Strengths and limitations
Our study had many strengths, including the use of population-based cancer registry data that meet the NAACCR high-quality data standards. We also had the ability to review detailed, population-based, state-level incidence data for the entire United States, making this the most comprehensive analysis of the COVID-19 pandemic’s impact on the number of newly diagnosed cancer cases in the United States. Our research data sets also allowed comparison of rates by year based on primary and successive submission files rather than reported statistics. Because we compared 2020 incidence at the time of submission with previous years of incidence at the time of submission, we did not overestimate the extent of the decline. However, we were limited by our proxy measures for health care capacity (deaths from COVID-19), health care access (breast cancer screening), and the extent of social disruption (policy restrictions) during the COVID-19 pandemic. These broad, state-level measures did not account for temporal fluctuations or for location differences. Furthermore, the policy restrictions index measured only the policies enacted and did not assess the extent to which policies were implemented.
CONCLUSION
Overall, cancer incidence and death rates continue to decline, representing changes in risk factors, increases in screening utilization, and advances in treatment. However, sustained disparities by race and ethnicity emphasize the need to fully understand the factors that create these differences so that they can be mitigated. Population-based incidence and mortality data play a vital role in informing cancer control efforts to help reduce the cancer burden in the United States.
Our analysis indicates that the decline in 2020 cancer diagnoses has not carried over into 2021 incidence rates. However, additional data years are needed to correctly interpret this decline and assess whether cases went undiagnosed or underreported, because the rates in 2021 were not greater than expected. The full impact of the decline in cancer diagnoses during 2020 on stage at diagnosis and survival will become clearer with additional years of incidence data. However, our results underscore the importance of public health policy to ensure continued access to cancer-related care, even during public health emergencies such as pandemics.
Effective cancer control and infectious disease control policies are not mutually exclusive and can be applied simultaneously to protect our nation’s health. Population-based incidence and mortality data play a vital role in informing cancer control efforts to help reduce the cancer burden in the United States.















