Impact of the COVID-19 pandemic in 2020 on the diagnosis, treatment, and prognosis of major cancers

BACKGROUND: The global COVID-19 pandemic in 2020 has exerted multidimensional effects on cancer, yet detailed investigations into these impacts remain largely insufficient. PATIENTS AND METHODS: We evaluated the impact of the COVID-19 pandemic in 2020 on cancers of six major sites, including lung & bronchus, female breast, prostate, colon & rectum, pancreas, and corpus & uterus. Annual changes in the number of new cases were assessed using the Surveillance, Epidemiology, and End Results (SEER)-22 dataset. The impact of the epidemic on diagnosis, treatment, and prognosis was analyzed using the SEER-17 dataset. Specifically, Ordinal logistic regression models were used to investigate the impact of the pandemic on stage. Logistic regression was used to elucidate the impact of the pandemic on diagnosis in different subgroups. Finally, we assessed both the time interval from diagnosis to treatment and cancer-specific survival (CSS). RESULTS: Compared with 2019, new diagnoses of the six major cancers decreased in 2020, with smaller changes in distant-stage cancers. Except for lung cancer (OR = 1.01, 95% CI, 0.97-1.05, P = 0.549), five of the six cancers diagnosed in 2020 tended to be at an advanced stage (all OR > 1, P < 0.005). During the pandemic, patients diagnosed with all six cancers in 2020 were more likely to have high-grade tumors, and for four cancers (excluding lung & bronchus and pancreatic cancers), patients were less likely to reside in areas with populations exceedi...