Original Article

A Detailed Scientometric Analysis of Global Publication Trends in COVID-19 Related Hematology and Oncology Research


  • Zeynep Tugba Guven

Received Date: 18.11.2021 Accepted Date: 15.02.2022 Med Bull Haseki 2022;60(2):92-98


A comprehensive scientometric analysis produced in hematology and oncology on coronavirus disease-2019 (COVID-19) research is lacking. This study presents a detailed analysis of COVID-19 related hematology and oncology literature.


The Web of Science (WoS) Core Collection was used for data collection. All published documents between 2020 and 2021 were included. The data exported from WoS enabled the extensive details of COVID-19 related literature in the hematology and oncology categories, including countries, institutions, authors, citations, and keywords. Scientometric interaction visualization of keywords and countries, and published journal co-authorships were created with free software. Worldwide participation of the countries in COVID-19 related hematology and oncology literature were shown by a graphic.


The search question displayed 4761 documents. The leading type of document was original articles (34.4%). The United States of America was the number one country, publishing 32.6% of all documents on COVID-19 related hematology and oncology research, followed by Italy, the United Kingdom, China, and France. Huazhong University of Science and Technology was the most contributing institution in the literature (2.8%), followed by Harvard Medical School and Memorial Sloan Kettering Cancer Center. The journal Blood has published the most documents about this field. The average citations per item was 7.2. The most used keywords over this period were “COVID-19,” “SARS-CoV-2,” “coronavirus,” and “cancer”.


The results of the present study may assist health professionals interested in this field to better figure out the current trends in COVID-19 related hematology and oncology research worldwide, and it can provide them to reach a more accurate information in a shorter time.

Keywords: COVID-19, coronavirus, SARS-CoV-2, hematology, oncology


By late 2019, a novel virus, also named severe acute respiratory syndrome coronavirus-2, had been identified as an etiologic agent for pneumonia patients in central China (1). This novel, high-spread virus has turned into a pandemic and has forced a burden on healthcare facilities. Patients with malignancy are a susceptible group due to the immunocompromised situations caused by their malignancy treatments, the malignancy itself, and comorbidities (2). Patients with cancer are more likely to have worse outcomes (mortality ranging from 11.4% to 35.5%) when diagnosed with Coronavirus disease-2019 (COVID-19) compared to patients without cancer (3,4). Oncology practice patterns have changed their daily routines; e.g., delay of treatment or less effective, safer treatment regimens, more frequent use of white blood cell growth factors (5). Similarly, hematological associations have rapidly published fresh interim recommendations for physicians, in particular for hematopoietic stem cell transplantation practice patterns during this COVID-19 virus outbreak time (6).

Bibliometrics analyzes publications produced in a specific discipline of academic literature to identify patterns and trends (7). Scientometrics, also known as the “science of science,” is a relatively new and popular statistical discipline that investigates all aspects of scientific literature (7-9). Parallel to the spread of pandemic effects all around the world, the scientific activity on COVID-19 has been rapidly elevated to a higher level with reduced peer-review processes and/or early access options in scientific journals. Thus, the rapid increase in COVID-19 literature in all fields of science was remarkable, especially after the second half of 2020. Though COVID-19 related publications about hematology and oncology are the trend topics of hematology and oncology practice during this pandemic, there has been no recent scientometric analysis of publications published on COVID-19 in the hematology and oncology literature.

This study presents a comprehensive analysis of academic literature about COVID-19 that has been published in hematology and oncology categories.


Study Design and Scientometric Analysis

This study was designed as a cross-sectional online literature analysis. The Web of Science (WoS) Core Collection (Thomson Reuters, New York, USA) was used for data collection. The data used in this study was obtained on April 29, 2021. A search question including keywords for “Covid” or “Covid-19” or “2019 novel coronavirus disease” or”coronavirus disease 2019” or “Covid-19 infection” or “SARS-CoV-2 disease”. All documents from the WoS database produced between 2020 and 2021 were included in the analysis. The data acquired from the abovementioned search query has been refined to only include the “Hematology” and “Oncology” fields by selecting hematology and oncology from the “WoS Categories” option. Data was exported from WoS in two formats: “full record and cited references” and “Tab-delimited for Mac”. A world map originated to show the global contribution of each country regarding publications in this category by the “Tableau Public” application, a free web source (7,10). Scientometric landscape visualization was performed by VOS viewer freeware (Leiden University, Leiden, Netherlands) (7,11). Citation counts represent all the data collected on April 29, 2021, when the WoS database search process was executed. Institutions were determined using the “Organizations-Enhanced” field. The records in England, Wales, Scotland, and Northern Ireland were merged into a single country, the United Kingdom (UK) (7).

Statistical Analysis

Data retrieved from online literature sources has been recorded on the Excel worksheet (Office 365 for Mac). Only the descriptive statistical methods (frequencies and percentages) were used for data analysis. Due to a lack of conventional statistical comparison methods, no p-values were obtained in this study.


Document Characteristics

The initial search query revealed 109,830 documents. After refinement for year periods and hematology/oncology categories, 4671 records were displayed during the period 2020-2021, 34.4% of which were original articles. A greater proportion of documents (2779, or 59.5%) were related to the oncology field. The documents published in 2020 were more numerous (3,624 vs. 999) than the documents published in 2021 as of the access date of this study. Oncology, hematology, cardiovascular system, radiology, and experimental research medicine were the trending research fields (64.9%, 40.3%, 10.4%, 4.8%, and 4%, respectively). The first document about this category was published in June 2020. The predominant language of the literature was English (98.7%), followed by French, German, Spanish, and Russian (0.5%, 0.5%, 0.1%, and 0.1%, respectively) (Table 1).

The Most Influential Authors, Journals, Meetings, and Institutions

Thachik J has published the maximum number of records with 25 articles after anonymous authors in this area (Table 1). The blood was the leading journal with 191 articles, followed by Clinical Cancer Research, Annals of Oncology, British Journal of Hematology, Transfusion, Thrombosis Research, and Journal of Thrombosis and Thrombolysis (n=161, 141, 138, 135, 112, and 104 items, respectively; Table 1). The Annual Meeting of the European Society for Medical Oncology-ESMO has been found to be the leading meeting with the highest record among meetings in this field. The most prolific organizations worldwide were in China and the United States. Huazhong University of Science and Technology has published the most records among organizations, with 127 documents, followed by Harvard Medical School and Memorial Sloan Kettering Cancer Center (Table 2).

Global Productivity

The United States of America (USA) was the leading country in COVID-19 literature in the Hematology and Oncology category and covered 32.6% of all productivity with 1523 items. Italy was the second leading country with 720 records, followed by the UK, China, and France (n=533, 513, and 298 items, respectively; Table 1). North America and Europe dominated the publication density around the world, but the least contribution to this field was observed in Africa (Figure 1).

Citations, Keyword Analysis, and a Network of Co-authorship for Countries and Institutions

A total of 13764 (11102 without self-citations) citations have been displayed with a h-index of 78. The average citations per item was 7.2. A full-length article by Klok, F. A. et al. titled “Incidence of thrombotic complications in critically ill ICU patients with COVID-19” and published in Thrombosis Research in 2020, has gained the maximum citations (Table 3). The most used keywords over this period were “COVID-19”, “SARS-CoV-2”, “coronavirus”, and “cancer” (Table 2). The scientometric network of keywords showed a “dichotomous pattern” in which COVID-19 was centered in the intersection (Figure 2). The USA was the most collaborative country, with 1523 documents, followed by Italy (Figure 3). The Journal of Blood and The Journal of Clinical Cancer Research were the leading source titles (Figure 4).


Scientometric studies display the publication trends and creativity of the countries, authors, and organizations in a certain area (7,8). Scientometrics enables the qualitative and quantitative assessment of academic literature and provides details of the most popular, active, and trending fields (7,12). Contrary to scientometrics growing popularity, there have been few articles investigating COVID-19 in the hematology and oncology fields (7).

Masjedi et al. (13) reported an overview of the oncology research of Iranian scholars between 1974 and 2019. The authors discovered an upward trend in all cancer research conducted by Iranian institutions, both in terms of productivity and citations received. However, the authors reported that complementary and alternative medicine treatment subfields have not been well-studied in the oncology literature produced by Iran. The authors included the research records indexed in either the Pubmed, Scopus, or WoS databases, which were different from this study (13).

A report by Acevedo et al. (14) focused on the distribution and trend of hematology and oncology research in Latin America. The authors reported that the most contributing country to the hematology and oncology fields in Latin America was Brazil (60% of all published documents) (14). In contrast to this study, only the abstracts presented at 4 major hematology and oncology annual scientific meetings were analyzed. Only approximately 18% of abstracts were published as full-text articles in a median of 1 year after presentation. In contrast to this study, the network analysis between authors, keywords, countries, and institutions of all documents was absent in that study.

An interesting paper has presented the details of the European cancer research perspective regarding cancer sites and the economic wealth status of countries (15). The authors found that cancer sites (e.g., central nervous system, blood cancers) seemed to be over-researched, whereas some gastrointestinal (e.g., pancreas, esophageal) cancers were under-researched (15). Furthermore, European countries were found to be insufficient contributors to cancer research  compared to their economic wealth status (15). The main distinction between this study and the aforementioned studies was that a comparison of contributing countries according to their economic status was lacking (15).

Andersen et al. (16) analyzed the global myeloma research published between 2005 and 2013. The authors reported that an annual increase of up to 43% was observed in global publication density for myeloma research (16). European countries and the USA showed the highest intra-cluster collaboration between each other (16). Similar to this study, USA-originated myeloma research clusters dominated the total productivity and citations (16).

In a bibliometric analysis of acute myeloid leukemia (AML) research conducted between 1999 and 2018, the authors reported an increasing trend in AML studies after 2009 (17). The Blood journal has published the highest number of AML studies (17). The USA and Kantarjian H were found to be the most productive countries and authors of AML research, respectively (17). Similarly, in this report, the journals Blood and USA dominated the COVID-19 research in the hematology and oncology categories.

More than 50% of the global productivity on COVID-19 in hematology and oncology category documents was achieved by the USA and a few European countries (Italy, UK, and France). Except for China, all the first 5 leading contributing countries in COVID-19 in hematology and oncology categories were developed ones. The relatively higher productivity of China could be attributed to the fact that the COVID-19 outbreak was first spread from this country to the world.

Kappi et al. (18) have recently reported a bibliometric analysis of world COVID-19 research that was comparable to this study. As of September 10, 2020, 17,133 published documents were related to COVID-19 (18). A logarithmic increase in COVID-19 research was observed as of April 29, 2021 by the time this study was conducted compared with the Kappi et al.’s (18) report (109,830 vs 17,133). This logarithmic increase trend was also observed in the hematology and oncology categories. A total of 988 (564 in oncology and 424 in hematology) documents were related to COVID-19 as of 10 September, which has increased more than 5-folds (3029 in oncology and 1883 in hematology) in a 7-months-period (18). At two time points, the USA was the leading country regarding global productivity of COVID-19 research in this category. As the outbreak of COVID-19 has spread worldwide, China’s contribution to global productivity in this category has decreased.

Study Limitations

This study has several limitations. First, though WoS has been speculated as a more valid data source than other counterparts, the data obtained from only one data source might not represent all documents (7,19). A similar study on COVID-19 in the hematology and oncology categories was absent to achieve healthy comparisons with this report (7). However, this is the first report focusing on COVID-19 related hematology and oncology research by scientometric analysis.


The results of this study may assist health professionals interested in this field to better figure out COVID-19 related hematology and oncology research worldwide. Beneficial information about dynamic and trending search topics in COVID-19 related hematology and oncology research fields may be obtained from this study. It can also contribute to researchers’ access to information in a shorter time. Policymakers worldwide could better allocate their resources to improving and monitoring COVID-19-related hematology and oncology research.


Ethics Committee Approval: Ethical approval was not applicable and not obtained for this study due to not including human or animal research.

Informed Consent: Informed consent was not obtained.

Financial Disclosure: The author received no financial support for the research, authorship, and/or publication of this article.

  1. Zhu N, Zhang D, Wang W, et al. A novel coronavirus from patients with pneumonia in China, 2019. N Engl J Med 2020;382:727-33.
  2. Liang W, Guan W, Chen R, et al. Cancer patients in SARS-CoV-2 infection: a nationwide analysis in China. Lancet Oncol 2020;21:335-7.
  3. Dai M, Liu D, Liu M, et al. Patients with cancer appear more vulnerable to SARS-CoV-2: a multicenter study during the COVID-19 outbreak. Cancer Discov 2020;10:783-91.
  4. Horn L, Whisenant JG, Torri V, et al. Thoracic Cancers International COVID-19 Collaboration (TERAVOLT): Impact of type of cancer therapy and COVID therapy on survival. Journal of Clinical Oncology https://ascopubs.org/doi/abs/10.1200/JCO.2020.38.18_suppl.LBA111
  5. Schrag D, Hershman DL, Basch E. Oncology practice during the COVID-19 pandemic. JAMA 2020;323:2005-6.
  6. EBMT C-aB. 2021 [updated 17.02.2021. Available from: https://www.ebmt.org/covid-19-and-bmt
  7. Güven S, Kılıç D. Bibliometric Analysis of the Articles Published in the Ophthalmic Epidemiology Journal Between 2002 and 2019. Turkiye Klinikleri J Ophthalmol 2020;29:324-32.
  8. Hood WW, Wilson CS. The literature of bibliometrics, scientometrics, and informetrics. Scientometrics 2001;52:291-314.
  9. Şenel E. Health and Ancient Beliefs: A Scientometric Analysis of Health Literature Related to Shamanism, Paganism and Spirituality. J Relig Health 2019;58:2019-35.
  10. Public T. Free Data Visualization Software. Available from: https://public.tableau.com
  11. Vosviewer. VOSviewer - Visualizing scientific landscapes. Available from: http://www.vosviewer.com/
  12. Broadus RN. Toward a definition of “bibliometrics”. Scientometrics 1987;12:373-9.
  13. Masjedi MR, Bazrafshan A, Mosavi Jarrahi M, et al. An Overview of Oncology Researches in Iran: A Scientometric Approach (1974–February 2019). Arch Iran Med 2020;23:181-8.
  14. Acevedo AM, Gómez A, Becerra HA, et al. Distribution and trends of hematology and oncology research in Latin America: a decade of uncertainty. Cancer 2014;120:1237-45.
  15. Begum M, Lewison G, Lawler M, Sullivan R. Mapping the European cancer research landscape: An evidence base for national and Pan-European research and funding. Eur J Cancer 2018;100:75-84.
  16. Andersen JP, Bøgsted M, Dybkær K, et al. Global myeloma research clusters, output, and citations: A bibliometric mapping and clustering analysis. PLoS One 2015;10:e0116966.
  17. Seo B, Kim J, Kim S, Lee E. Bibliometric analysis of studies about acute myeloid leukemia conducted globally from 1999 to 2018. Blood Res 2020;55:1-9.
  18. Kappi M, Sab MC, Biradar BS, Bagalkoti VT. Bibliometric Study of World COVID-19 Publication Output. Shanlax International Journal of Arts, Science and Humanities 2021;8:86-95.
  19. Kendall S. LibGuides: PubMed, Web of Science, or Google Scholar? A behind-the-scenes guide for life scientists. So which is better: PubMed, Web of Science, or Google Scholar. 2016:5-2.