S1392
Interdisciplinary - Health economics & health services research
ESTRO 2026
Digital Poster 1574 The use of survival statistics in the ‘Green’ and ‘Red’ journals Levi R. Klanke, Rob van Os, Lukas J.A. Stalpers Radiotherapy, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands Purpose/Objective: ’Patient survival is generally accepted as the principal criterion for measuring the effectiveness of treatment in cancer’ (Ederer et al., 1961)1. In 2014, Nature published a ranking of the most cited scientific papers2. The original paper by Kaplan and Meier (KM) was the most frequently cited paper in statistics, and 11th in all sciences3. However, an update in 2025 showed that the KM paper ranking had plummeted to the 44th place4. In order to understand the possible decline in the relevance of survival analysis, we investigated its use in radiation oncology. Material/Methods: All 1,240 original articles in the ‘Green’ journal (Radiotherapy & Oncology) and the ‘Red’ (IJROBP) in 2019 and 2024 were reviewed. All clinical, biological and physics investigations presenting original data were screened individually for the use of survival statistics and the methods employed, as well as whether the source of the original method was referenced. Data were analysed descriptively, with group comparisons performed using chi-squared and Fisher's exact tests. Web of Science™ was used to analyse the citation history of the KM paper since its publication in 1958. Results: Of the 840 clinical investigations in the Green and Red journals, 524 (62.4%) reported survival statistics. All studies used the KM method, with 370 (44.1%) using it as part of a Cox regression analysis. Other methods were rarely used. No significant differences were observed in the use of survival statistics between the Green and Red journals (p = 0.13), nor between 2019 and 2024 (p = 0.32). Only 1.91% (11 out of 575) of articles using KM analysis cited the original 1958 paper. The number of citations of the original KM publication registered in the Web of Science™ increased until 1997, followed by a gradual decline. By November 2025, the article had accumulated 52,305 citations (see Figure).
Conclusion: The majority (62.4%) of clinical radiotherapy papers use survival statistics, highlighting the enduring importance of survival analysis in this field of research. Even though more recent and advanced survival analysis methods exist, the KM method remains the standard approach. The KM paper was cited in fewer than 2% of papers using the method, suggesting that being among the most frequently cited papers is probably not a reliable indicator of scientific relevance or impact. The infrequent use of more advanced survival analysis techniques may be due to limited exposure to these alternative methods during medical training5. References: 1. Ederer F, Axtell LM, Cutler SJ. Natl Cancer Inst Monogr, 1961; (6): 101–21.2. Van Noorden R, Nature, 2014; 514(7524): 550-33. Kaplan EL, Meier P. J Am Stat Ass, 1958; 53(282), 457–481.4. Van Noorden R, Nature, 2025; 640(8059): 591.5. MacDougall M, Cameron HS, Maxwell SRJ. BMC Med Educ, 2019;19:448. Keywords: survival analysis, Kaplan-Meier, bibliometrics Digital Poster 1846 Impact of Ultra-Hypofractionated Radiotherapy on Operational Efficiency Ilya Lvovich, Rimma Bahchevan, Salem Billan, Tomer Charas
Radiotherapy Institute,Oncology Department, Rambam Health Care Center, Haifa, Israel
Purpose/Objective: To evaluate the impact of increasing use of Ultra- Hypofractionated Radiotherapy (UHFR) on total treatment starts, daily patient load, and operational efficiency . The analysis also explores the correlation between UHFR expansion, normal fractionation (NF) and operational strain, as indicated by the institutional
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