Overview of publications on psycho-oncology
A total of 1921 papers were detected through a comprehensive literature search. After the screen strategies, a total of 968 published papers met the inclusion criteria for this study. On the whole, there was a growing trend both in publications and citation in the past 21 years (Fig. 2A). The year 2019 ranked the most productive year with 109 publications, followed by the year 2018 with 97 papers and the year 2017 with 90 papers. Moreover, by the last retrieval time the citation frequency was 16,865, which reached a peak of 2,375 in year 2019, followed by 2,064 in year 2018 and 1,707 in year 2017.
The 968 publications were drawn from 55 countries/regions. The 55 countries/regions distributions were divided into 7 different colors of clusters according to the appearance for the average time (Fig. 2B). It is worth mentioning that South Africa, Mexico, Qutar, Saudi Arabia and Lebanon had recently begun to make most contributions to this field.
The 968 publications involved 48 researching directions by intrinsic analysis function of WOS. Except for the two largest but non-specific researching directions of oncology and psychology, the article numbers of main researching directions were shown in Fig. 2C.
Co-authorship Analysis Of Countries/regions
In this study, the VOSviewer 1.6.14 software was used to analyze the network visualization of co-authorship relationships between 55 different countries/regions. Only countries/regions with a minimum of five articles were included. A total of 32 countries/regions were identified, however, among which Singapore was not connected to each others. Thus, the remaining 31 countries/regions were divided into seven clusters, as shown in Fig. 3A. Furthermore, the co-authorship analysis involved in 55 different countries/regions was shown in Supplementary Fig.S1.
The top 10 countries/regions ranked by the number of documents published were shown in Fig. 3B. The United States of America (USA) was the clear leader in terms of documents quantity (286) followed by the Germany (143) and Australia (130), total link strength (131) followed by the Australia (79) and Germany (55), and Norm. citations (345.36) followed by the Germany (146.01) and Australia (128.10), respectively.
Co-authorship Analysis Of Organizations
A total of 1,452 organizations were represented in the published 968 articles. Only organizations with a minimum of 10 articles were included in co-authorship analysis. A total of 39 organizations were identified, which were divided into five clusters, as shown in Fig. 3C. This co-authorship analysis revealed that Newcastle university ( Newcastle, Australia) had closely collaborations with Hunter Medical Research Institution (Newcastle, Australia), University of Sydney (Sydney, Australia) and McGill University (Montreal, Canada). Furthermore, the co-authorship analysis involved in 1452 organizations was shown in Supplementary Fig.S2.
The top 10 organizations ranked by the number of documents published were shown in Fig. 3D. Among these 10 organizations, three organizations were respectively located in Canada and Australia, and one organization was respectively located in USA, England, Italy and Germany. The most productive organization in terms of published articles was Memorial Sloan-Kettering Cancer Centre (MSKCC ) in New York, USA (34), followed by Newcastle University (29) and McGill University (28). Newcastle university had the highest total link strength (44), followed by University of Sydney (35), McGill University (22) and University of Queensland (Queensland, Australia) (22). In addition, University of Sydney had the highest Norm. citations (43.81), followed by University of Ferrara (Ferrara, Italy) (39.73) and Harvard University ( Boston, USA) (30.87, not in Fig. 3D).
Co-authorship Analysis Of Authors
Analysis using the VOSviewer 1.6.14 software revealed that the 968 articles totally included 4,152 authors, in which the same one author’s name may had several different ways of writing. Only authors with a minimum of five articles were included in co-authorship analysis. A total of 54 authors were identified, which were divided into 12 clusters, as shown in Fig. 3E. Some of the 54 authors in the network map were not connected to each other, while the network map also showed massive collaborations between authors, such as Luigi Grassi and Rosangela Caruso both from University of Ferrara in Italy.
The top 10 authors ranked by the number of documents published were shown in Fig. 3F. Luigi Grassi published the greatest number of papers (26), followed by Tatsuo Akechi from Nagoya City University Hospital in Japan (20) and Anja Mehnert from University of Leipzig in Germany (18). The authors who had the three highest total link strength were Luigi Grassi (50), Tatsuo Akechi (49) and Rosangela Caruso(38), respectively. Nevertheless, the authors ranked by the three highest Norm. citations were Luigi Grassi (40.95), Anja Mehnert (32.55), and Alex J Mitchell (25.76, not in Fig. 3F) from Leicester Partnership Trust (Leicester, UK).
Co-occurrence Analysis Of Author Keywords
A total of 1,768 author keywords in the 968 papers on psycho-oncology were extracted by the VOSviewer 1.6.14 software. As shown in Fig. 4A, 37 author keywords defined as terms that co-occurred the minimum number of 10 time within title and abstracts in all papers were analyzed using a co-occurrence network analysis tool in the VOSviewer 1.6.14 software. In this analysis, these 37 author keywords were classified into 4 large clusters. In addition, the distribution of these 37 author keywords according to the average time they appeared in the articles showed that “Fear of cancer recurrence” may indicate the main research hotspots in recent years (Supplementary Fig.S3). Furthermore, the co-occurrence analysis of 1,768 author keywords was shown in Supplementary Fig.S4.
The top 10 author keywords ranked by the number of co-occurrence were shown in Fig. 4B. The most commonly used keywords were “Quality of life”(131), “Depression”(90) and “Breast cancer”(68), respectively. Furthermore, the author keywords with the three highest total link strength were “Quality of life”(139), “Depression”(127) and “Anxiety”(95),respectively.
Bibliographic Coupling Analysis Of Journals
A total of 300 journals had published articles in field of psycho-oncology. Using the VOSviewer 1.6.14 software, 33 journals published 5 or more papers were included in the bibliographic coupling analysis of journals, as shown in Fig. 4C. These 33 journals were classified into 5 large clusters.
The top 10 journals ranked by the number of published documents were shown in Fig. 4D. More than half of the publications were published in the top 10 journals (578, 59.71%). Obviously, Psycho-Oncology had taken a leading position in terms of published documents (190), total link strength (11,279) and Norm. Citations (260.40). It indicated that Psycho-Oncology could be considered the most influential journal in the field of research for psycho-oncology. Of note, Supportive Care in Cancer ranked the second for the total number of publications (64), total link strength (5,489) and Norm. Citations (57.90). Journal of Psychosocial Oncology ranked the third for published papers (44) and total link strength (3,328), while Cancer ranked the third for Norm. Citations (44.64).
Co-citation Analysis Of Cited References
By the VOSviewer 1.6.14 software, the analysis revealed that the 968 articles totally cited 28,311 references. Forty-four references with a citation frequency greater than 20 were selected to create the co-citation map, as shown in Fig. 4E. All of them were classified into four clusters. These cited references were published between 1983 and 2014, meanwhile 6 of them were published in Journal of Clinical Oncology. Among the first author of these 44 articles, Jimmie Holland from MSKCC (New York, USA) contributed 3 articles, while no other first author contributed more than 3 articles [15–17].
The top 10 most-cited articles were shown in Fig. 4F. Zigmond AS and Snaith RP from St. James’ University Hospital (Leeds, Yorkshire, England) had published the first most-cited article (126 times), which were about Hospital Anxiety and Depression Scale (HADS) [18]. The HADS was a self-rated screening questionnaire detecting mild degrees of anxiety and depression. Although it was designed for general medical hospital outpatients, it had been widely used in primary care. Citation frequency of the second most-cited article was 95 time, which was contributed by Zabora James from the Johns Hopkins University School of Medicine (Baltimore, USA). This article entitled “The prevalence of psychological distress by cancer site” was published on Psycho-Oncology in 2001 [19]. The third most-cited article (72 times) was written by Alex J Mitchell from Leicester Partnership Trust (Leicester, UK), which was a meta-analysis study aimed to quantitatively summarise the prevalence of depression, anxiety, and adjustments disorders in oncological, haematological and palliative-care settings [20]. Besides, the aforementioned three papers also ranked respectively the top three for the total link strength.