Giannakodimos et al raise concerns regarding some methodological limitations of our article on the impact of prebiopsy multiparametric magnetic resonance imaging (mpMRI) on detection of prostate cancer (PC) in Switzerland [1]. We thank the authors for highlighting some of the potential issues and welcome the opportunity to clarify some points.
First, our study was purely observational in nature and relied on cancer registration data and retrospective patient chart review combined with data from a survey among urologists practicing in Switzerland. The ecological study design inherently introduces several obvious methodological limitations, and any associations or trends cannot be interpreted as causal. This is fully and transparently discussed in the article. Nevertheless, this approach remains valuable for assessing real-world trends and generating hypotheses for further evaluation. Furthermore, readers should consider the primary objective of the study, which was to evaluate the adoption of mpMRI-guided biopsy for PC detection and to determine whether the general trends that would be expected on the basis of prior randomized controlled trials occurred over the period during which MRI was increasingly used in the Swiss health care system.
In their letter, the authors state that various factors such as MRI quality, the number of biopsies, biopsy strategy, prostate-specific antigen (PSA), and PSA density were not assessed. It is well established that these factors influence PC detection. However, we clearly stated that data from Swiss cancer registries contain limited information about the diagnostic pathway. Hence, we conducted a survey to assess the regional and temporal uptake of MRI use to complement the registry data. Given the study design, it was neither the aim nor possible to assess the accuracy and reproducibility of diagnostic modalities, or to adjust for such confounding factors. However, these limitations and the role of potential confounders were addressed in our discussion [1].
Furthermore, Giannakodimos et al argue that the article does not sufficiently address PC etiology and fails to provide data on long-term outcomes. Regarding both points, we refer to our reply above: While a more in-depth etiological evaluation and assessment of long-term outcomes such as survival would be highly interesting, this was not the aim of our study and would obviously require a different study design. The resulting difficulties in interpreting the results from our study with respect to etiology and the longer-term impact of mpMRI-guided biopsy in Switzerland are clearly mentioned in our conclusions [1].
Last, the authors conclude that “the findings should be interpreted with caution”. We strongly disagree with this wording, as the conclusions of the manuscript are purely descriptive and highlight that the changes occurred in parallel with the uptake of mpMRI rather than being caused by it. It is unclear exactly what should be interpreted with caution, as the study provides only descriptive, real-world data from Switzerland and we explicitly stated that the true cause of the clearly observable shift in risk groups remains uncertain.
Conflicts of interest: The authors have nothing to disclose.
References
- 1.Scherer T.P., Menges D., Bieri U., et al. Impact of prebiopsy multiparametric magnetic resonance imaging on prostate cancer detection in Switzerland. Eur Urol Open Sci. 2025;73:1–7. doi: 10.1016/j.euros.2025.01.004. [DOI] [PMC free article] [PubMed] [Google Scholar]