And The Stoning Continues

A couple months ago, the world of ureterolithiasis was upended by The Lancet and its publication of a trial examining medical expulsive therapy.  In direct contrast to the prior (worthless) Cochrane Review, this large, reasonably-designed trial, does away with the notion of universal benefit of alpha- and calcium channel-blockers for MET.

Following on its heels comes the publication of another trial of moderate size, but with even more rigorous follow-up.  Rather than previously mentioned trial’s “urologic intervention” as the patient-oriented outcome, this trial used a disease-oriented outcome.  This trial, enrolling patients with distal ureteral stones, required patients to under go CT at 28 days to definitively assess for stone passage.

The trial randomized 403 patients to either tamsulosin 0.4mg daily for 28 days or identical placebo, but, unfortunately, 87 did not ultimately undergo second CT.  Of the patients that did undergo CT, there was no statistically significant difference in stone passage: 87.0% tamsulosin vs. 81.9% placebo, an absolute difference of 5.0% (95% CI -3.0 to 13.0).  Of the 87, 77 were available for follow-up regarding urologic intervention.  If a combined endpoint of CT passage and lack of urologic intervention is used, the results remain unchanged.

However, the trial was designed specifically to enroll adequate numbers of patients with stones of 5-10mm in size – targeting adequate sample size with which to include at least 49 patients to detect a difference in stone passage of 5 to 25%.  They ultimately randomized 103 large stones and completed imaging or clinical follow-up on 77.  The difference in stone passage rate in the large stones was 83.3% in the tamsulosin group, compared with 61.0% with placebo, for an absolute difference of 22.4% (95% CI 3.1 to 41.6).

So, what’s the takeaway – from decades of poor-quality studies, the recent Lancet publication, and now this?  There’s probably some signal in the noise – and that signal, all along, has probably been these large, distal stones.  Unless there’s a truly diminished risk of stone passage, there’s never been any reasonableness to the use of MET – but if passage rates are ~60%, the likelihood of a clinically meaningful benefit is finally possible.

If I’ve obtained a CT in a patient and diagnosed a large, distal stone – I am offering tamsulosin.  Otherwise, no.

Rory Spiegel also shares his typically excellent similar evaluation of the evidence: EM Nerd

“Distal Ureteric Stones and Tamsulosin: A Double-Blind, Placebo-Controlled, Randomized, Multicenter Trial”