An approach to COVID‑19 and oncology: From impact, staging and management to vaccine outcomes in cancer patients: A systematic review and meta‑analysis.

The COVID-19 pandemic has had a global impact, with >771 million confirmed cases and 6 million deaths reported by October 2023. Cancer patients, due to their immunosuppressed status, face an increased infection risk and higher COVID-19 complications. The present study aimed to assess clinical outcomes in COVID-19-infected cancer patients, focusing on mortality rates and other aspects, providing valuable insight for better protection and outcomes. This systematic review was conducted by searching the PubMed, Cochrane and Embase databases from August 2023 following the PRISMA guidelines. Studies from 2020 to 2023 pertaining to the impact of COVID-19 on patients previously diagnosed with malignancies were considered. Inclusion criteria entailed a pre-existing malignancy diagnosis, confirmed COVID-19 infection and an impact of COVID-19 on any aspect of the patient's cancer management. Studies written in English were exclusively reviewed. Post-COVID-19 malignancy diagnoses, case reports, review articles and data-insufficient studies were excluded. Screening and consensus on eligibility were carried out by a team of four authors, with disputes resolved by a non-screening author. Data extraction was performed by a five-author team, detailing study and population characteristics, as well as cancer patient outcomes related to COVID-19. Cross-checking was conducted by the same team, with conflicts resolved by a third author. The review of 27 studies explored COVID-19's impact on oncology, revealing diverse sample sizes (1,807,559 to 177 participants). Studies spanned various cancer types, including gastric adenocarcinoma, breast, lung, gynecologic, colorectal and non-melanoma skin cancer. Mortality rates were higher among cancer patients with COVID-19 compared to those without. Gastric adenocarcinoma exhibited a 5.9% mortality rate. Thoracic cancer patients faced elevated mortality and gastrectomies decreased. A meta-analysis (10 studies, 5,151 patients) showed a 19.1% mortality rate for COVID-19-infected cancer patients, contrasting with 1% for non-COVID-19 cancer patients (5 studies, 54,528 patients). The odds ratio for mortality in non-COVID-19 vs. COVID-19 cancer patients was 0.1036 (3 studies, 3,496 patients). Cancer patients consistently faced elevated mortality during the pandemic, with specific cancers showing unique impacts. Gastric adenocarcinoma exhibited a significant COVID-19 mortality rate. Patients with thoracic cancer faced increased risks, influencing surgical trends. Meta-analysis revealed an overall elevated mortality rate among COVID-19-infected cancer patients compared to non-COVID-19 counterparts.