The impact of cancer on the severity of disease in patients affected with COVID-19: an umbrella review and meta-meta-analysis of systematic reviews and meta-analyses involving 1,064,476 participants.

During the COVID-19 pandemic, cancer patients were among the most vulnerable patient groups to the SARS-CoV-2 infection effects. This paper aimed to conduct an umbrella review and meta-meta-analysis to determine the severity of disease in cancer patients affected by COVID-19. The umbrella review and meta-meta-analysis were undertaken according to the PRISMA and MOOSE guidelines. The PubMed/Medline, Web of Science, and Scopus databases were searched for published papers from the start of the pandemic through July 18, 2022. The pooled effect sizes (ES) and odds ratios (ORs) were calculated using a random effect model in the 95% confidence interval (CI) for ICU (Intensive Care Unit) admissions and mortality in cancer patients infected with SARS-CoV-2. Egger's linear regression test, schematic illustrations of funnel plots, and Begg and Mazumdar's rank correlation tests were used to quantify the possibility of publication bias. The pooled ES was calculated based on 1,031,783 participants, and mortality was significantly increased in cancer patients affected by COVID-19 (OR = 2.02, %95 CI: 1.74-2.35, p < 0.001). The pooled ES for ICU admission was also significantly increased in cancer patients infected with SARS-CoV-2 (OR = 1.84, %95 CI: 1.44-2.34, p < 0.001). As a result, this synthesis of systematic reviews and meta-analyses by the meta-meta-analysis method revealed that disease severity is higher in cancer patients affected by COVID-19. Since cancer patients are a more sensitive and specific patient group, they should be evaluated more carefully, especially during the COVID-19 pandemic and other pandemics that may occur in the future.