50 years of radiotherapy research: evolution, trends and lessons for the future
Berger, T. Noble, D. J. Shelley, L. E. Hopkins, K. I. McLaren, D. B. Burnet, Neil G Nailon, W. H.
Berger, T.
Noble, D. J.
Shelley, L. E.
Hopkins, K. I.
McLaren, D. B.
Burnet, Neil G
Nailon, W. H.
Citations
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Abstract
Purpose or Objective
Rapid and relentless technological development in an ever-more globalized world has shaped the field of
Radiation Therapy (RT) in which we practise today. We hypothesised that a data-driven analysis of the
literature from the last 50 years would improve our understanding of where we have come from, and where
we are now, and hence provide insights on the future direction and requirements of the field.
Materials and Methods
The PubMed database was searched with the keywords cancer radiotherapy yearly from 1970 to 2019. This
yielded 358,114 publications distributed over time as shown in Fig.1 and for which, the authors’ names and
affiliations were collected and analysed. In particular, the evolution of the geographic distribution of research
output was investigated from 1990 to 2019 and illustrated in Fig.2. Considering the 20 journals with the most
significant research contribution, several metrics on publications per author were calculated. Furthermore, to
understand the evolution of cancer therapies used in conjunction with RT, the proportion of publications
returned with keywords pertaining to therapies detailed in Fig.1 was assessed. Results
Despite the sharp rise in RT publications, the proportion of RT articles relative to alternative cancer therapies
decreased from 64% (2,221 articles) in 1970 to 31% (18,284) in 2019. Conversely, 4% of articles dealt with
chemotherapy in 1970 against 30% 50 years later.
The proportion of first authors not publishing as last authors increased from 58% in 1970 to 84% in 2000. The
median [Q1-Q3-90th] number of previous publications per first author was 2[2-2-15] and 2[2-7-14] for last
authors in 1985 which increased to 5[2-13-34] and 16[5-38-80] in 2019.
Between 1990 and 2019, Africa totalled 0.5-1% of the global research output while South America remained
<2%. During the 30 years studied, the contribution of Europe and North America decreased from 47 to 42% and
38 to 26%, respectively. Conversely, the proportion of articles from Asia more than doubled increasing from 12
to 26%. Oceania followed a similar trend with an increase from 1.7 to 3.3%. Conclusion
In the past 50 years, the proportion of RT articles significantly decreased compared to other cancer therapies.
Also, the pace of publication was multiplied by 6 between 1985-2019 for the 10% most productive last authors.
Researchers now face fiercer competition as shown by the increasing proportion of first authors that will never
publish as a last author. Additionally, RT research is extremely unequally distributed globally. Since research
activity is inherent to delivery of high quality clinical care, this contributes to the global inequity of RT
services. Africa and South America represent 23% of the world’s population yet contributed to ~3% of RT
articles. North America and Europe contributed to 2/3 of research output despite being home to <15% of the
world’s population - Learning from these trends is crucial for the future not only of RT research but also of
effective, equitable cancer care.
Description
Date
2021
Publisher
Collections
Keywords
Type
Meetings and Proceedings
Citation
Berger T, Noble DJ, Shelley LE, Hopkins KI, McLaren DB, Burnet NG, et al. 50 years of radiotherapy research: evolution, trends and lessons for the future. Radiotherapy and Oncology. 2021;161:S1237-S9.