Abstract
INTRODUCTION: Urinary drainage (ureteral stenting or percutaneous nephrostomy) is commonly used for malignant ureteral obstruction (MUO), but optimal indications remain unclear. [(99m)Tc]Tc-mercaptoacetyltriglycine (MAG(3)) renal scintigraphy assesses urinary tract obstruction and may help identify patients who can avoid drainage. The aim of this case series was to investigate the impact of urinary drainage guided by MAG(3) findings on renal function in MUO patients. METHODS: We retrospectively reviewed 44 MUO patients who underwent MAG(3) scintigraphy between April 2020 and January 2022. Based on results, 29 patients underwent urinary drainage and 15 patients were treated conservatively. Patients were classified by MAG(3) excretion pattern and followed by renal function, pyelonephritis and flank pain at 1, 2, 3 and 6 months. RESULTS: Among the conservative group (n = 15), MAG(3) patterns included non-function (n = 7), delayed excretion (n = 7) and obstruction (n = 1). No patients developed renal deterioration or pyelonephritis, though one patient underwent drainage for contralateral flank pain. Among the drainage group (n = 29), MAG(3) patterns included obstruction (n = 16), delayed excretion (n = 8), declined excretion (n = 3) and non-function (n = 2). CONCLUSION: Fourteen of 15 patients treated conservatively after MAG(3) scintigraphy experienced no renal complications during 6 months of follow-up. MAG(3) scintigraphy may support individualised decision-making and help avoid unnecessary drainage. Conservative management may be appropriate for patients with a non-functional MAG(3) pattern.