# A Qualitative Review of Clinical Decision‐Making Using [99m Tc]Tc‐Mercaptoacetyltriglycine Renal Scintigraphy in Patients With Malignant Ureteral Obstruction

## TL;DR

This study shows that a specific kidney scan can help doctors decide whether to avoid unnecessary procedures in patients with blocked ureters due to cancer.

## Contribution

The study demonstrates that MAG3 renal scintigraphy can guide safe conservative management in selected malignant ureteral obstruction cases.

## Key findings

- 14 out of 15 patients managed conservatively had no kidney complications over 6 months.
- MAG3 scintigraphy helped avoid unnecessary drainage in patients with non-functional kidney patterns.
- Conservative management was safe for patients with non-functional MAG3 patterns.

## Abstract

Urinary drainage (ureteral stenting or percutaneous nephrostomy) is commonly used for malignant ureteral obstruction (MUO), but optimal indications remain unclear. [99mTc]Tc‐mercaptoacetyltriglycine (MAG3) 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 MAG3 findings on renal function in MUO patients.

We retrospectively reviewed 44 MUO patients who underwent MAG3 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 MAG3 excretion pattern and followed by renal function, pyelonephritis and flank pain at 1, 2, 3 and 6 months.

Among the conservative group (n = 15), MAG3 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), MAG3 patterns included obstruction (n = 16), delayed excretion (n = 8), declined excretion (n = 3) and non‐function (n = 2).

Fourteen of 15 patients treated conservatively after MAG3 scintigraphy experienced no renal complications during 6 months of follow‐up. MAG3 scintigraphy may support individualised decision‐making and help avoid unnecessary drainage. Conservative management may be appropriate for patients with a non‐functional MAG3 pattern.

This case series evaluated the clinical utility of [99mTc]Tc‐MAG3 renal scintigraphy in managing malignant ureteral obstruction (MUO). Renal scintigraphy‐guided decision‐making allowed safe conservative management in selected patients, particularly those with a non‐functional excretion pattern, and helped avoid unnecessary urinary drainage.