Table 3.

Strengths and limitations of conventional preoperative evaluation tools.

Tool	Primary role	Major strengths	Key limitations relevant to KSS	Representative refs
CT urography	Initial diagnosis and staging	High diagnostic accuracy; defines anatomy and hydronephrosis.	May miss subtle/flat disease and incompletely reflect biologic aggressiveness before KSS.	(3, 4, 30)
Voided/selective cytology	Noninvasive adjunct for grade-oriented assessment	High specificity, especially for high-grade disease.	Moderate sensitivity; false reassurance remains a problem in low-grade or limited disease.	(38–40)
Diagnostic ureteroscopy	Direct visual assessment and targeted sampling	Clarifies anatomy and allows lesion-directed evaluation.	Invasive; repeat procedures add burden and visual appearance still imperfectly reflects biology.	(41, 42)
Ureteroscopic biopsy	Tissue confirmation and approximate grading	Essential when management depends on histology.	Sampling error, undergrading, and understaging remain important.	(20, 21)
Clinicopathologic models	Integration of imaging, cytology, grade, size, and focality	Useful real-world framework for triage.	Still built mainly on morphology and surrogates rather than direct tumor biology.	(8, 30, 75)

KSS, kidney-sparing surgery; RNU, radical nephroureterectomy; URS, ureteroscopy; CTU, computed tomography urography; ctDNA, circulating tumor DNA; cfDNA, cell-free DNA; MRD, molecular residual disease; NOC, non–organ-confined; CNV, copy-number variation.