News from Clinical Research Office of the Endourological Society (CROES)

The clinical research office of the endourological society (CROES) was established in 2008 to compile answers to questions arising from real clinical practice in the field of endourology. The first percutaneous nephrolithotomy (PCNL) study was a great success, gathering 5803 cases from 96 institutions around the world in 2 years and yielding 27 publications in peer-reviewed journals. A variety of questions on PCNL were answered in this project, such as the impact on the outcome of factors such as the patients' condition, disease status, or the surgical technique used. The big impact of this study is shown by the 196 articles that have cited the first publication of this project over the past 4 years. ¹ The second study on ureteroscopic stone managements (URS study) gathered 11,885 cases, and the results will be used in 22 articles, some of which have already been published.

CROES has been effective in collecting many cases in a short time, as shown by the PCNL and URS studies. In addition, institutions from all over the world participated, including those in developing countries. Integrity of the data is assured by the audit committee and studies are published quickly, thanks to the publication office. CROES's success is also because of the strong organization established under the leadership of Jean de la Rosette with the full support of the Endourological Society.

Well-designed randomized controlled studies (RCTs) are considered the gold standard of clinical evidence. However, the majority of RCTs are performed with a rather narrow window for inclusion criteria for patients, diseases, institutions, and physicians, which results in a gap between the results of the RCTs and real clinical practice. In particular, questions related to surgical procedure are difficult to answer through RCTs, because procedures vary depending on the surgeon, institution, or the patient's conditions. As an example, the CROES PCNL study came to a different conclusion with regard to the dilation method for the nephrostomy site than what has been recommended by RCTs. ² CROES established the usefulness of multi-institutional database studies as another source of clinical evidence. A large clinical database has been established in Japan, called the National Clinical Database (NCD), that has gathered information on a million surgical procedures and their outcomes on a nationwide base. ³ Even though the NCD has not received as much data inspection as CROES, it has already yielded several important articles. ⁴ The importance of CROES-type multi-institutional database studies will increase as more people recognize the value of real-world clinical evidence.

Now, CROES has evolved to include RCTs and a disease registry. The NBI study was effective in gathering 965 cases from 26 centers, demonstrating that CROES and its audit committee could also work as a platform for RCTs and serve as a central data repository. Another RCT called SPIES is ongoing. The renal mass study and upper tract urothelial cancer (UTUC) registry are registration systems for small renal masses and upper urotherial tumors, respectively, regardless of the treatment modality used for each patient. A long-term follow-up for up to 10 years, which can only be realized with the support and strong solidarity of the members of the Endourological Society, will reveal much new evidence about these diseases.

CROES has added value to the Endourological Society as a world-wide research platform. To expand the society's activities and realize its goals, the continued strong support of the society for CROES projects is critical.