All in all, the bibliometric data of 17,387 original articles (n) was retrieved. Out of this pool, 16,230 articles were written in English (93.3%). The second most used language was French with 2.47% (n = 430), followed by German (n = 395) and Russian (n = 172).

The number of articles on EC were initially remaining below n = 10 until the end of the Second World War 1945. Afterwards, a moderate but steady increase could be observed until 1980. From then onwards, the numbers increased much faster until they reached their maximum in 2016 with n = 1331 articles. The numbers of citations (c) showed a similar development with peaks in 1994 (c = 10.631) and 2001 (c = 15.258)—until its maximum in 2005 (c = 16.032). Afterwards, the annual amount decreased very rapidly with only small peaks in 2008 (c = 14.951) and 2012 (c = 13.664). Comparing the citation rates (cr) of the publication years, the years 1946 (cr = 56.6), 1998 (cr = 47.5) and 1961 (cr = 41.4) were outstanding.

The information of the country of origin was given in the field tags of 16,686 articles (95.9%). This pool was the source of the geographical analyses and represents the timespan between 1973 and 2017. Previous to this time frame, the geographical data is non-existent, respectively very limited.

The evaluation of absolute numbers (Fig. 1a) shows that China is the most publishing country with n = 4448 articles on EC, followed by Japan (n = 3828) and the USA (n = 3125). Following behind with some distance, Germany and the UK reached n = 999 and n = 952, respectively.

Density equalizing map projection of the absolute numbers of the publishing countries. a Number of articles. b The development of the relative distribution of the most publishing countries in 5-year intervals from 1973 until 2017

The chronological development of the relative proportion of the most publishing countries is shown in Fig. 1b. Chinas share increased from 1.39 to 45.30%. In contrast, the USA proportion decreased from 30.09 to 13.53%. The order of the five most publishing countries in the first evaluation interval (1973–1977) is as follows: USA (n = 65), France (n = 57), UK (n = 21), Germany (n = 18), and Japan (n = 14). From 1988 to 2007, Japan published the most part of the OC-articles. The last time evaluation period (2013–2017) is ranked as follows: China (n = 2722), Japan (n = 928), USA (n = 813), UK (n = 268), and Germany (n = 193).

The USA received the most citations (c = 103,833), followed by Japan (c = 81,099), China (c = 61,726), and also at some distance by the UK (c = 27,607) and Germany (c = 26,095) (Fig. 2a).

Density equalizing map projection of citation parameters. a Number of citations. b Modified h-index. c Citation rate (threshold ≥ 30 articles)

Assessing the modified h-indices (hI) of the publishing countries (Fig. 2b) the order of the first five countries is as follows: USA (hI = 134), Japan (hI = 106), China (hI = 89), UK (hI = 78) and Germany (hI = 73). Regarding the average citation rate (cr) of countries with more or equal 30 articles (threshold), Belgium is the leading country with cr = 53.75, followed by Singapore (cr = 38.76), USA (cr = 33.22), Norway (cr = 32.10) and Canada (cr = 31.40) to name the best five (Fig. 2c).

To give consideration to the differences regarding the number of inhabitants and the economic strength (threshold ≥ 30 articles), the ratios of the number of articles/population in mill. (RPOP) and the number of articles/GDP in 1000 bn USD (RGDP) were analyzed (Fig. 3). It is notable that High-income (HI) countries were ranked higher in principle regarding both parameters, especially Japan (RPOP = 30.21, RGDP = 776.15), Netherlands (RPOP = 29.97, RGDP = 588.98), and Sweden (RPOP = 29.55, RGDP = 586.23). In this analysis, the countries with a lower income level are set back. Especially China—ranking first regarding the absolute evaluation numbers—has been thrown back.

Socio-economic parameters of the countries publishing on esophageal cancer, threshold ≥ 30 articles, GDP gross domestic product, USD US-Dollar, countries income groups according to the World Bank classification

Looking at the association between the publication output of the countries and the overall expenditures on Research and Development in mill. US-Dollars (R&D), [26] respectively the countries’ epidemiological burdens [27] (OECD countries), differences regarding the adequacy of individual research endeavors reveals. For the linear regression of the numbers of articles and the R&D expenditures a coefficient of determination (r2) = 0.79 can be calculated. The correlation is strongly significant (Spearman p