The significance of functional renal obstruction in predicting pathologic stage of upper tract urothelial carcinoma.

BACKGROUND AND PURPOSE: Assessing the severity of upper tract urothelial carcinoma (UTUC) has been difficult because of inadequate biopsy specimens. Additional predictive parameters of disease stage would be useful when deciding a treatment plan; it has been suggested that preoperative hydronephrosis can be a surrogate. We examined the relationship between preoperative ipsilateral renal obstruction identified by imaging with final pathologic stage after nephroureterectomy (NU) for UTUC. We then analyzed those patients with ipsilateral renal obstruction and examined if tumor location is associated with an advanced pathologic stage.

METHODS

Patients who underwent NU for UTUC between the years 2001 to 2013 were analyzed and relevant staging studies and pathology were reviewed. Criteria for ipsilateral renal obstruction were defined by the presence of a delayed nephrogram on CT scan, renal cortical atrophy with associated hydronephrosis on cross-sectional imaging, and/or >10% split function discrepancy on nuclear renal scintigraphy with associated hydronephrosis.

RESULTS

Eighty-two patients met inclusion criteria; 26/82 (31.7%) had locally advanced disease (pT3/T4), while 56/82 (63.4%) had organ-confined (≤pT2) disease. Of the patients with pT3/T4 disease, 10/26 (38.5%) demonstrated radiographic evidence of functional obstruction of the ipsilateral renal unit; similarly, in patients with ≤pT2 disease, 21/56 (37.5%) demonstrated ipsilateral renal obstruction (P=0.93). Of the patients with ipsilateral renal obstruction, in those patients with pT3/T4 disease, 7/10 (70.0%) had ureteral tumor involvement while 9/21 (42.9%) patients with ≤pT2 disease had tumor in the ureter (P=0.25).

CONCLUSIONS

This study suggests that renal obstruction by radiographic analysis does not always predict advanced stage. In addition, there is a trend toward advanced stage when a patient has radiographic evidence of ipsilateral renal dysfunction and a ureteral tumor.