Assessing the effect of the COVID-19 pandemic on 1-year cancer survival in the United States.

The COVID-19 pandemic had a substantial impact on health-care delivery. We used the Surveillance, Epidemiology, and End Results (SEER) data to assess changes in 1-year relative survival and competing risk probabilities of cancer and non-cancer death for patients diagnosed in 2018 Q2 (pre-pandemic) and 2020 Q2 (pandemic). For all cancer sites combined, 1-year relative survival declined from 82.3% in 2018 Q2 to 77.5% in 2020 Q2, with the steepest declines seen in stomach, leukemia, and liver cancers. However, survival improved nearing pre-pandemic levels during 2020 Q3. Competing risk survival measures revealed that the decline in 1-year survival was driven by increases in both the probability of dying of cancer (rising from 15.4% to 19.2%) and of other causes, including COVID-19 (rising from 3.8% to 5.2%). The pandemic led to substantial declines in survival and increased mortality from both cancer and other causes for patients diagnosed in 2020 Q2.