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Minerva Urol Nefrol. 2019 Feb;71(1):96-100. doi: 10.23736/S0393-2249.18.03357-X. Epub 2019 Jan 2.

The role of vascular clamping during robot-assisted partial nephrectomy for localized renal cancer: rationale and design of the CLOCK randomized phase III study.

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Department of Urology, ASL Abruzzo 2, Chieti, Italy -
Unit of Urology, Department of Medical and Surgical Specialties, Radiological Sciences, and Public Health, Spedali Civili Hospital of Brescia, University of Brescia, Brescia, Italy.
Data Methods and Systems Statistical Laboratory, University of Brescia, Brescia, Italy.
Department of Urology, San Donato Hospital, Arezzo, Italy.
Department of Urology, San Bassiano Hospital, Bassano Del Grappa, Vicenza, Italy.
Department of Urology, Misericordia Hospital, Grosseto, Italy.
Unit of Urology, Careggi Hospital, University of Florence, Florence, Italy.
Department of Urology, Policlinico of Abano, Abano Terme, Padua, Italy.
Department of Urology, ASL Abruzzo 2, Chieti, Italy.


To outline the design and rationale of clock, a large, phase III randomized controlled trial which examines the role vascular clamping during robot-assisted partial nephrectomy (RAPN) for localized renal cancer. To be eligible for study entry, patients must have normal coagulative function, preoperative estimated glomerular filtration rate (eGFR) >60 mL/min, normal contralateral kidney and a single renal mass with RENAL Score ≤10. Eligible patients are to be randomized in a 1:1 ratio between two arms. Randomized allocation was assigned by a permuted block design, stratified by center. Allocation arm was notified by the study internet-based e-form, managed by an independent software house. Arm A=RAPN with ischemia; Arm B=RAPN without ischemia. At any moment, from randomization to the end of the procedure, the investigators could amend the indication given by randomization and shift to the alternative clamping option, detailing the timing and reasons of their decision. CLOCK is a randomized controlled trial, which addresses two questions relating to the management of localized renal cancer treated by RAPN with or without ischemia: 1) what is the impact of the surgical technique on long-term renal function; 2) what are the factors influencing the shift from one technique to the other. The study will be completed 24 months after the last enrollment.

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