Methodical strength and limitations
The enormous amount of scientific publications and the increasing range of journals makes it absolutely necessary to separate the wheat from the chaff. Not only for the individual scientists, but also for planners and funders it is getting more and more difficult to assess the available literature as well as the scientific environment. A long-sighted and globally adapted research is in demand, especially regarding medical issues. So, the NewQIS platform select important medical topics to carry out comprehensive bibliometric reviews. All bibliometric studies depend on the representative status of the database. The WoS is certainly one of the most prolific literature and citation data bases worldwide, but nevertheless, some disadvantages have to be discussed. The English-bias has already been shown in a variety of articles [
29,
30]. Even so, possible faulty citing [
31,
32] leads to methodological limitation, since the citation numbers are underlying all citation parameters. Therefore, the interplay of the applied citation parameters seems to provide the highest benefit. Likewise, the generation of the applied search term is controversial. The more extensive the data base, the more faultily integrated entries can disturb its quality, and the resulting validity can be brought into question. On the other hand, a data base should be as complete as possible because otherwise it harbours the risk of neglecting important data. Hence, it is a tightrope walk to elaborate a scientifically adequate term and the appropriate strategy.
Discussion of results
The development of the number of publications follows a known pattern. It has been proofed earlier that the increase of articles number show an exponential progression (Table
1) [
33]. Nevertheless, the visible maxima of average citation numbers per year illustrate an association with the most prolific articles (Table
2) [
34‐
37].
Table 1
Socio-economic parameters of 10 top ranked countries regarding the RGDP = articles/GDP in 1000 bn UDS (GDP = gross domestic product), RPOP = articles/population, total in mill. inhabitants (threshold = 30 articles)
Japan | 3828 | 4.93 | 126.70 | 776.16 | 30.21 |
Netherlands | 510 | 0.86 | 17.02 | 588.98 | 29.97 |
Sweden | 292 | 0.49 | 9.88 | 586.23 | 29.55 |
Finland | 89 | 0.23 | 5.50 | 372.07 | 16.19 |
Ireland | 114 | 0.32 | 4.95 | 351.53 | 23.02 |
Switzerland | 172 | 0.49 | 8.18 | 347.97 | 21.03 |
United Kingdom | 952 | 2.78 | 64.43 | 341.46 | 14.78 |
Taiwan | 375 | 1.12 | 23.46 | 333.33 | 15.98 |
South Africa | 238 | 0.73 | 54.30 | 323.24 | 4.38 |
France | 858 | 2.73 | 66.84 | 313.48 | 12.84 |
Denmark | 75 | 0.26 | 5.59 | 283.23 | 13.41 |
Belgium | 140 | 0.51 | 11.41 | 275.27 | 12.27 |
Germany | 999 | 3.98 | 80.72 | 251.07 | 12.38 |
Norway | 87 | 0.36 | 5.27 | 238.55 | 16.52 |
Austria | 96 | 0.41 | 8.71 | 230.82 | 11.02 |
Australia | 256 | 1.19 | 22.99 | 215.31 | 11.13 |
China | 4448 | 21.27 | 1373.54 | 209.12 | 3.24 |
Italy | 391 | 2.22 | 62.01 | 176.05 | 6.31 |
USA | 3125 | 18.56 | 324.00 | 168.37 | 9.65 |
Greece | 46 | 0.29 | 10.77 | 158.35 | 4.27 |
Iran | 229 | 1.46 | 82.80 | 156.96 | 2.77 |
South Korea | 293 | 1.93 | 50.92 | 151.89 | 5.75 |
Canada | 246 | 1.67 | 35.36 | 146.95 | 6.96 |
Hungary | 34 | 0.27 | 9.87 | 127.06 | 3.44 |
Spain | 205 | 1.69 | 48.56 | 121.30 | 4.22 |
Portugal | 32 | 0.30 | 10.83 | 107.71 | 2.95 |
Israel | 31 | 0.30 | 8.17 | 104.38 | 3.79 |
Singapore | 50 | 0.49 | 5.78 | 102.69 | 8.65 |
Czech Republic | 32 | 0.35 | 10.64 | 91.19 | 3.01 |
Poland | 87 | 1.05 | 38.52 | 82.70 | 2.26 |
Turkey | 91 | 1.67 | 80.27 | 54.49 | 1.13 |
Russia | 155 | 3.74 | 142.36 | 41.39 | 1.09 |
Brazil | 115 | 3.13 | 205.82 | 36.68 | 0.56 |
Argentina | 30 | 0.88 | 43.89 | 34.11 | 0.68 |
India | 281 | 8.72 | 1266.88 | 32.22 | 0.22 |
Table 2
The most cited articles
USA | Devesa et al. | 1998 | 1484 | Changing patterns in the incidence of esophageal and gastric carcinoma in the United States |
South Korea, Belgium, Switzerland, China, Japan, Germany, Italy, Russia, Australia | Bang et al. | 2010 | 1312 | Trastuzumab in combination with chemotherapy versus chemotherapy alone for treatment of HER2-positive advanced gastric or gastro-oesophageal junction cancer (ToGA): a phase 3, open-label, randomised controlled trial |
USA | Herskovic et al. | 1992 | 1301 | Combined chemotherapy and radiotherapy compared with radiotherapie alone in patients with cancer of the esophagus |
Netherlands | van Hagen et al. | 2012 | 1117 | Preoperative chemoradiotherapy for esophageal or junctional cancer |
UK | Cunningham et al. | 2008 | 1025 | Capecitabine and oxaliplatin for advanced esophagogastric cancer |
France, Belgium | Bosset et al. | 1997 | 898 | Chemoradiotherapy followed by surgery compared with surgery alone in squamous-cell cancer of the esophagus |
USA | Cooper et al. | 1999 | 872 | Chemoradiotherapy of locally advanced esophageal cancer—long-term follow-up of a prospective randomized trial (RTOG 85-01) |
France | Mandard et al. | 1994 | 842 | Pathological assessment of tumor-regression after preoperative chemoradiotherapy of esophageal-carcinoma |
USA, Canada | Kelsen et al. | 1998 | 837 | Chemotherapy followed by surgery compared with surgery alone for localized esophageal cancer |
USA | Urba et al. | 2001 | 813 | Randomized trial of preoperative chemoradiation versus surgery alone in patients with locoregional esophageal carcinoma |
Additionally, the incidence of EAC in the Western countries has increased tremendously in the last decades [
8], so that the significant increase of publications on EC in the last years seems reasonable [
38]. The high incidence and prevalence rates of the so called
Esophageal Cancer Belt leading from Iran, Central Asia to North China cause the high participation of China ranking first. Nearly half of the new OC cases worldwide occurred in China in 2012 [
6]. Here, OC ranked 4th regarding the incidence rate after lung, stomach and liver cancer [
38] and also regarding the mortality rate [
39]. After all, Iran still ranks 15th with 229 articles. Other
belt-
countries can be neglected.
The publication output regarding the ratios of the socio-economic factors mat the findings of Man et al. which emphasize the dominancy e.g. of Scandinavian countries, certainly because of the National Cancer Registries that are delivering the clinical data [
40‐
42]. The main difference of both study results is the position of Japan. Despite the low incidence and mortality rate in Japan [
43] the research effort on EC is remarkable. Man et al. [
44] positioned Japan in the lower part of the ranking regarding the R
POP value. In our review, Japan ranks second regarding the absolute numbers of the publication output, and ranks first regarding both socio-economic features (R
POP, R
GDP) (Table
2). Regarding the influence of the Total Research Spending, Man et al. [
44] found Japan equally high ranked as in our study. This was confirmed by our findings that show that Japan position regarding their expenditures on R&D was extremely positive. It showed a slightly discarded position in comparison to their high ICR. Japan already established several institutions, working groups, and studies with the focus on EC. The Japan Esophageal Society for example, publishing the Esophagus Journal, generated the
Comprehensive registry of EC. Additionally, the Japan Esophageal Cancer Group has been created as one of the first two Groups of the Japan Clinical Oncology Group (JCOG) in 1978. However, with only 7% international collaborations, for Japan can be calculated the lowest cooperation percentage of all HI-countries publishing on EC.
Despite their ranking among the best five, the publication performance on EC of the USA and the UK is relatively low compared with other studies [
45‐
47]. An analysis of research funding on cancer burden measured by estimated medical costs and years life lost (YLL) stated the underfunding of EC research in both countries [
48]. The correlation analysis of this study regarding the connection of the article numbers and the ICR showed a positive participation of US-American scientists based on the Globocan numbers of 2012 [
27]. However, there has recently been an extreme accumulation of EAC cases, so that these findings have to be adapted in future. Despite the currently alarming figures of EAC in the US, the NCI decreased the funding of EC research by 15% in 2012. Only about 0.5% of the overall budget was invested. And the American Cancer Society funded only eight OC projects out of 1165 cancer projects [
48]. This was confirmed by our findings. They positioned the number of articles on EC in comparison to their overall R&D expenditures last among the OECD countries.
After the findings of this study, the UK positioned itself with a high ICR of 14 and n = 952 article behind. However, the UK works on EC seems to be in line when looking at their overall R&D expenditures. Also, Carter et al. [
49] found that the under-funded research on EC, shifted somewhat towards an improved funding from 2000 to 2010. This may be due to the largely nationalized medical system, while in the US only a scarce state health system is established. This led to more prevention measures, more check-ups and more available medical data in UK [
49].
Comparing the publication output of other European Countries, a back lying can be stated when looking at the high ICR in 2012. Here, the Netherland, Ireland, Belgium has to be highlighted. Especially the most affected countries in Europa are publishing comparatively little on EC. Looking at the highly affected countries worldwide with ICR over 15, only China and Japan show a justified research endeavor on EC. Other highly affected countries—especially developing countries—did not play a role in the research landscape of EC.
Therefore, the targeted promotion of established science systems and their scientists under the current conditions is highly required and the most affected countries without financial recourses for adequate research efforts have to be supported and included in the global scientific network. Here, a rethink must take place, which leads to a redistribution of resources.