Upper Urinary Tract Transitional Cell Tumors Diagnosis: Role of CT- Urography

Research Article

Austin J Radiol. 2015;2(3): 1017.

Upper Urinary Tract Transitional Cell Tumors Diagnosis: Role of CT- Urography

Recaldini C1, Mangini M1*, De Bon M1, De Chiara M1, Giorlando F1, Duka E1, Marconi A2, Carrafiello G1 and Fugazzola C1

1Department of Radiology, University Hospital of Varese, Italy

2Department of Urology, University Hospital of Varese, Italy

*Corresponding author: Mangini M, Department of Radiology, University Hospital of Varese, V.le Borri 57, 21100, Italy

Received: February 18, 2015; Accepted: March 18, 2015; Published: March 20, 2015

Abstract

Objective: The purpose of this study was to point out CT Urography (CTU) potentials and limitations for the diagnosis of Upper Urinary Tract Transitional Cell Carcinoma (UUT-TCC) and to suggest how and when to use invasive second-line investigations.

Materials and Methods: 66 patients with a suspected UUT-TCC were examined with CTU; 52/66 patients underwent also Retrograde Pielography (RP). Reference standards were histopathology and the 24-month clinical and imaging follow-up. Moreover the T stage of 15 tumors, treated by surgery, was assessed.

Results: 21/66 patients had a final diagnosis of UUT-TCC; CTU showed a sensitivity of 90.5%, a specificity of 84.4%, a Positive Predictive Value (PPV) of 73.1% and a Negative Predictive Value (NPV) of 95%. The overall accuracy of CTU in evaluation of T parameter was 80%.

In the subgroup of 52 patients, CTU and RP showed both a sensitivity of 85.7%, a specificity respectively of 84.4% and 82.2%, a PPV of 46.2% and 42.8%, a NPV of 97.4% and 97.3%. In 7 cases, false positive both at CTU and RP, biopsy allowed a definitive diagnosis of tumor absence. Moreover in 1 case, false negative both at CTU and RP with positive urinary cytology, endoscopy and biopsy showed a small superficial tumor.

Conclusion: CTU, complemented by urinary cytology and cystoscopy, is the technique of choice for UUT-TCC diagnosis and staging. In cases of positive CT findings, RP-guided biopsy is advisable to complete the diagnostic work-up; nevertheless, if CTU is negative and cytology is positive, endoscopy is indicated.

Keywords: Transitional cell carcinoma; CT urography; Retrograde Pielography

Abbreviations

CTU: Computed Tomographic Urography; UUT-TCC: Upper Urinary Tract Transitional Cell Carcinoma; RP: Retrograde Pielography; PPV: Positive Predictive Value; NPV: Negative Predictive Value; IVU: Intravenous Urography; TP: True Positive; TN: True Negative; FP: False Positive; FN: False Negative; RNU: Radical Nephro-Ureterectomy

Introduction

Computed Tomographic Urography (CTU) is currently considered to be the gold standard imaging technique for Upper Urinary Tract Transitional Cell Carcinoma (UUT-TCC) detection [1]. Many studies demonstrated that it is more accurate than Intravenous Urography (IVU) [2,3]. Furthermore, CTU diagnostic accuracy has also been confirmed by a recent literature meta-analysis [4].

However CTU may not detect small superficial urothelial tumors [5], especially if there is incomplete ureteral opacification by contrast medium [6]. In addition, polypoid or stenosing lesions identified with CTU are not always malignant. Therefore the Positive Predictive Value (PPV) of CTU is 53% - 63.2% [7,8], because there are several benign conditions that may simulate tumor [9]. Considering these limitations, the CTU findings must always be supplemented by urine cytology and cystoscopy, if a malignant lesion is suspected. The use of more invasive second-line investigations, such as diagnostic ureteroscopy and Retrograde Pyelography (RP), may be necessary.

The purpose of this study is to point out CTU potentials and limitations for the diagnosis of UUT-TCC; moreover, we aim to suggest when and how to use second line imaging techniques, based on the review of our experience during two years.

Materials and Methods

Study population

Two radiologists (CR and MDB) retrospectively reviewed, in a consensual matter, 92 patients with a suspicion of malignant upper urinary tract tumor, who had undergone CTU and/or RP at our hospital between 1st January 2009 and 31st December 2010. Of these 92 patients, 26 were excluded because of a lack of an established final diagnosis by histhologic examination and/or clinical and imaging follow-up at 24 months.

The remaining 66 patients (51 men and 15 women; age range 41-89 years; mean age 69.4 years) formed the study population (Table 1): 32/66 patients were referred for a positive voided urine cytology for malignant cells (C5: 8 patients), suspicious (C4: 13 patients) or atypical (C3: 11 patients), associated with haematuria (micro or macroscopic) and negative cystoscopy for bladder malignant lesions.

The remaining 34 patients were referred for malignancy because of a new diagnosis of bladder urothelial carcinoma at cystoscopy (7/34 patients, associated with haematuria and positive or suspicious urine cytology), or a prior diagnosis of urothelial tumors (27/34 patients: 23/27 with prior bladder TCC, including 5 patients with recurrent bladder tumor at cystoscopy; 2/27 with prior upper tract TCC; 2/27 with prior bladder and upper urinary tract TCC). The urine cytologic results in the follow-up patient group were: 11/27 positive urine cytology (C5), 6/27 suspicious cytology and 10/27 benign cytology (<C3); moreover 14 of these 27 patients had haematuria.

Fifty-two (52/66, 78.8%) patients underwent both CTU and RP; the mean interval between CTU (performed first in all patients) and RP was of 35.2 days; 14/66 patients (21.2%) underwent only CTU.

The final diagnosis was confirmed by histological examination in 28/66 patients (Table 2). The histological specimens were obtained by surgery in 13 cases (12 nephroureterectomy, 1 ureterectomy), by both biopsy (n=1 case by Ultrasound [US]-guidance; n=3 cases by RP-guidance according to the technique proposed by Carrafiello et al. [10]) and surgery (1 nephrectomy, 3 nephroureterectomy) in 4 cases; by biopsy alone in 9 cases (n=1 case by US-guidance; n=8 cases by RP- guidance), by ureteroscopy with biopsy (with subsequent laser ablation) in 2 cases.