Preliminary results of a randomized controlled trial of prophylactic shockwave lithotripsy for small asymptomatic renal calyceal stones

Objective To report a prospective, randomized study to determine whether pr ophylactic extracorporeal shockwave lithotripsy (ESWL) is justified as a tr eatment for small, asymptomatic calyceal stones. Patients and methods The study included 228 patients with small (<15 mm tot al diameter) asymptomatic calyceal stones; 113 patients were randomized to undergo ESWL and 115 to the control group who were kept under observation. Outcome measurements included the stone-free rate, requirement for addition al treatment, symptoms, quality of life and renal function. Results In all, 200 patients had at least one annual follow-up; all outcome measurements reported were those at the most recent follow-up (mean 2.2 ye ars, range 1-5). In the ESWL group 28 patients (28%) were stone-free, compa red with 16 (17%) in the observation group (odds ratio 1.95, 95% confidence interval, CI, 0.97-3.89, P = 0.06), Additional treatment in the form of an algesics, antibiotics, ESWL, stent insertion and ureteroscopy, was required in 21 (21%) patients in the observation group and 15 (15%) in the ESWL gro up (odds ratio 0.66, 95% CI 0.32-1.37, P = 0.27), Ten patients in the obser vation group required invasive procedures, vs none in the ESWL group, There was no evidence of differences in the symptoms, quality of life or renal f unction tests between the arms of the trial at the final follow-up. Conclusions Prophylactic ESWL for small asymptomatic renal calyceal stones does not appear to offer any advantage to patients in terms of stone-free r ate, quality of life, renal function, symptoms or hospital admissions. Howe ver, a policy of observation is associated with a greater risk of requiring more invasive procedures, A longer follow-up is required to assess the val idity of these preliminary findings.