key: cord-0836836-i7ivpjy2
authors: Yekedüz, Emre; Utkan, Güngör; Ürün, Yüksel
title: Response to letter entitled: Re: A systematic review and meta-analysis: The effect of active cancer treatment on severity of COVID-19
date: 2021-05-17
journal: Eur J Cancer
DOI: 10.1016/j.ejca.2021.04.010
sha: cff37e66a5ff7c2bfb5ca7460d6785ad240bd8a9
doc_id: 836836
cord_uid: i7ivpjy2

nan

. In contrast to our results, they established that surgery within the 30 days before COVID-19 diagnosis had a negative impact on the prognosis of those patients. In fact, they claimed that we had missed out on the inclusion of some published manuscripts in our meta-analysis. However, we have several objections to this issue. It should be noticed that we included the studies that compared the effect of COVID-19 in patients with cancer who underwent surgery and those who did not. In this regard, the article conducted by COVIDsurg, included in the meta-analysis of Zou et al., compared patients who underwent cancer surgery and those who underwent non-cancer surgery [2] . In fact, this study did not meet the inclusion criteria of our meta-analysis. The other study included in the metaanalysis of Zou et al. was conducted by Lara et al. [3] However, this study was published on October 01, 2020. Of note, in our meta-analysis, we included the studies published in PubMed up to September 01, 2020. Similarly, the study conducted by Yang F. et al. was published in October 2020 [4] . Thus, we might have missed out on these studies in our PubMed search due to the time restriction. Furthermore, in the study conducted by Yang K. et al., we could not access the odds ratio to compare patients who underwent surgery and those who did not. Of note, in this study, no patient underwent surgery in the COVID-19 non-survivor arm [5] . Thus, we did not include this study in our meta-analysis. Finally, in the study of Zhang et al., there was no treatment arm that only included patients who had surgery. In this regard, the local therapy arm had patients performed radiotherapy and/or surgery [6] . It was hard to interpret the results for patients who underwent surgery. Because of this reason, we did not include this study in our meta-analysis. On the other hand, the aforementioned studies, except for those conducted by COVIDsurg, were enrolled a small number of patients [2] . For instance, two patients underwent surgery in the study of Yang F. et al. [4] Similarly, in the study of Lara et al., 11 patients underwent surgery within 30 days before COVID-19 diagnosis and two patients had a severe COVID-19 [3] . Taken together, the difference between our results and the meta-analysis of Zou et al. might be explained by the high number of patients in the study of COVIDsurg [2e4,6] .

By the end of the COVID-19 pandemic's first year, a huge number of studies evaluated the clinical outcomes of patients with cancer in the pandemic. In this regard, multinational collaborations are paving the way for more accurate results about the impact of COVID-19 on patients with cancer. Recently, a study, including 422 patients with cancer treated with locoregional therapy within three months of COVID-19 diagnosis, has been published by COVID-19 and Cancer Consortium (CCC19). No increased risk was observed for severe disease and death in patients with cancer who underwent locoregional cancer therapy [7] .

Again, we thank the authors for their interest in our meta-analysis and for giving us a chance to clarify the results about the patients with cancer who underwent surgery.

None.

A systematic review and metaanalysis: the effect of active cancer treatment on severity of COVID-19

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

COVID-19 outcomes of patients with gynecologic cancer

Clinical characteristics and outcomes of cancer patients with COVID-19

Clinical characteristics, outcomes, and risk factors for mortality in patients with cancer and COVID-19 in Hubei, China: a multicentre, retrospective, cohort study

Outcomes of novel coronavirus disease 2019 (COVID-19) infection in 107 patients with cancer from Wuhan

Association of clinical factors and recent anti-cancer therapy with COVID-19 severity among patients with cancer: a report from the COVID-19 and cancer Consortium

The authors declare no conflict of interest.