Highly cited German research contributions to the fields of radiation oncology, biology, and physics: focus on collaboration and diversity

Use and application of geographical restrictions in systematic reviews with the aim of including studies about Germany: An update of a methodological review

BACKGROUND

In systematic reviews (SRs), geographical limitations in literature searches can aid in focussing research efforts. A methodological review published in 2016 examined the approaches SR authors use to identify studies about Germany, analysing 36 SRs.

OBJECTIVE

The aim of this study was to update the original review.

METHODS

We conducted a literature search on PubMed for SRs synthesising evidence from studies about Germany published between 22 January 2016 and 7 June 2022. Two reviewers independently performed study selection and data extraction. We evaluated the application of search syntax for restricting studies to those about Germany using the peer review of electronic search strategies criteria. The updated findings were reported and summarised alongside those of the original review.

RESULTS

Thirty-two additional SRs were newly included (total = 68). Geographic restrictions were applied in 57 SRs, representing 72% in the original review and increasing to 97% in the newly included SRs. Moreover, there was an increased use of truncations and field tags.

CONCLUSION

Although geographical restriction methods are increasingly utilised, additional tools are necessary to enhance the robustness of search strategies. The development of a dedicated geographical search filter would facilitate the identification of studies about Germany.

Scientific impact of studies published in temporarily available radiation oncology journals: a citation analysis

The purpose of this study was to review all articles published in two temporarily available radiation oncology journals (Radiation Oncology Investigations, Journal of Radiosurgery) in order to evaluate their scientific impact. From several potential measures of impact and relevance of research, we selected article citation rate because landmark or practice-changing research is likely to be cited frequently. The citation database Scopus was used to analyse number of citations. During the time period 1996-1999 the journal Radiation Oncology Investigations published 205 articles, which achieved a median number of 6 citations (range 0-116). However, the most frequently cited article in the first 4 volumes achieved only 23 citations. The Journal of Radiosurgery published only 31 articles, all in the year 1999, which achieved a median number of 1 citation (range 0-11). No prospective randomized studies or phase I-II collaborative group trials were published in these journals. Apparently, the Journal of Radiosurgery acquired relatively few manuscripts that were interesting and important enough to impact clinical practice. Radiation Oncology Investigations’ citation pattern was better and closer related to that reported in several previous studies focusing on the field of radiation oncology. The vast majority of articles published in temporarily available radiation oncology journals had limited clinical impact and achieved few citations. Highly influential research was unlikely to be submitted during the initial phase of establishing new radiation oncology journals.

Normal tissue studies in radiation oncology: A systematic review of highly cited articles and citation patterns

Radiation therapy is one of the cornerstones of modern multidisciplinary cancer treatment. Normal tissue tolerance is critical as radiation-induced side effects may compromise organ function and quality of life. The importance of normal tissue research is reflected by the large number of scientific articles, which have been published between 2006 and 2010. The present study identified important areas of research as well as seminal publications. The article citation rate is among the potential indicators of scientific impact. Highly cited articles, arbitrarily defined as those with ≥15 citations, were identified via a systematic search of the citation database, Scopus. Up to 608 articles per year were published between 2006 and 2010, however, <10% of publications in each year accumulated ≥15 citations. This figure is notably low, when compared with other oncology studies. A large variety of preclinical and clinical topics, including toxicity prediction, the dose-volume relationship and radioprotectors, accumulated ≥15 citations. However, clinical prevention or mitigation studies were underrepresented. The following conclusion may be drawn from the present study; despite the improved technology that has resulted in superior dose distribution, clinical prevention or mitigation studies are critical and must receive higher priority, funding and attention.

Correlation between article download and citation figures for highly accessed articles from five open access oncology journals

Different approaches can be chosen to quantify the impact and merits of scientific oncology publications. These include source of publication (including journal reputation and impact factor), whether or not articles are cited by others, and access/download figures. When relying on citation counts, one needs to obtain access to citation databases and has to consider that results differ from one database to another. Accumulation of citations takes time and their dynamics might differ from journal to journal and topic to topic. Therefore, we wanted to evaluate the correlation between citation and download figures, hypothesising that articles with fewer downloads also accumulate fewer citations. Typically, publishers provide download figures together with the article. We extracted and analysed the 50 most viewed articles from 5 different open access oncology journals. For each of the 5 journals and also all journals combined, correlation between number of accesses and citations was limited (r = 0.01-0.30). Considerable variations were also observed when analyses were restricted to specific article types such as reviews only (r = 0.21) or case reports only (r = 0.53). Even if year of publication was taken into account, high correlation coefficients were the exception from the rule. In conclusion, downloads are not a universal surrogate for citation figures.