Prognostic impact of perirenal fat stranding on oncologic outcomes in ureteral urothelial carcinoma

Purpose: Perirenal fat stranding (PRFS) is defined as linear areas of soft-tissue attenuation in the perirenal space that can result from ureteral obstruction. We analyzed the prognostic impact of PRFS on outcomes in patients with ureteral urothelial carcinoma (UC). Materials and Methods: Overall, 126 patients evaluated preoperatively by computerized tomography (CT) scan and diagnosed with ureteral UC following nephroureterectomy between January 2001 and May 2018 were included. We analyzed associations between oncologic outcomes and secondary signs such as hydronephrosis and PRFS. Results: Overall, 68 patients (54.0%) showed PRFS on preoperative CT scans. The patients’ mean age was 66.33±9.49 years. A high pT stage (≥T3) was seen in 47 patients (37.3%) and high-grade tumors were seen in 90 patients (71.4%). Lymphovascular invasion (LVI) was seen in 15 patients (11.9%), and 5 (4.0%) were at the pN1 stage. Multivariate Cox analysis showed that cT stage≥3, PRFS, pT stage≥3, tumor grade, LVI, and pN1 stage were independent prognostic factors of recurrence-free survival (RFS) and cancer-specific survival (CSS) (all p<0.05). Conclusions: PRFS was found to be an independent prognostic factor for RFS and CSS. PRFS is easily detectable in preoperative CT imaging and may be useful for improving the prediction of oncologic outcomes of ureteral UC. Therefore, PRFS along with other important preoperative CT findings can help urologists give preoperative advice to patients with ureteral UC before surgical management.