Independent validation of the 2002 UICC TNM staging system for papillary renal cell carcinoma in a multicenter cohort

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Background: Papillary renal cell carcinoma (pRCC) is the second most malignant histologic subtype in nephrectomy specimens. To date, the most recognized staging system to stratify renal cancer patients is the 2002 UICC TNM classification system. Its accuracy for predicting patient outcome for pRCC is unknown. Methods: From ten urologic institutions in Germany follow-up data on 675 patients with pRCC were collected. In most cases histologic slides were available and central pathologic review was performed. The Kaplan-Meier method was used to derive the cumulative cancer-specific survival. For multivariate analysis of prognostic factors, a Cox regression analysis was performed. Results: 498 (74.1%) patients had organ-confined tumor stages (≤pT2). Synchronous distant metastases in the entire group occurred in 58 (8.7%) patients and 69 (11.2%) others developed metastatic disease during follow-up. Cancer-specific survival (CSS) was significantly related to TNM stage and histologic grading in univariate as well as in multivariate analysis (all p < 0.0001). 5-year CSS in pT1b tumors (90.0%) was significantly shorter compared to pT1a tumors (98.3%) (p = 0.017). Patients with ≥pT3 were at high risk for metastases (50.6%), while metastatic disease associated with ≤pT2 tumors occurred in 7.8% (p < 0.0001). Once metastatic disease was present, prognosis was poor (5-year CSS: 7.2%). Age was associated with a worse prognosis in the subgroup of ≥pT3 tumors in univariate (p = 0.026), but not in multivariate analysis. Conclusions: The 2002 UICC TNM staging system is applicable for pRCC. Clinical and radiologic follow-ups should be offered in frequent intervals to patients with venous thrombus and/or locally advanced disease. The role of age remains unclear, but should not be underestimated at risk stratification after tumor resection.

No significant financial relationships to disclose.

[Renal cell cancer does not show a typical perfusion pattern in contrast-enhanced ultrasound]

PURPOSE

Grayscale ultrasound has improved the outcome of renal cell cancer (RCC), since most significant RCCs are discovered coincidently during routine abdominal ultrasound examinations. The CT scan is currently the method of choice for further evaluation. The therapeutic approach depends on the results of the CT scan. The purpose of this study was to evaluate whether RCCs would show typical vascularization patterns in contrast-enhanced ultrasonography (CEUS).

METHODS AND MATERIALS

We examined 30 patients with solid renal tumors before surgery with CEUS using the microbubble contrast agent SonoVue (Bracco, Italy). All patients had suspected malignant lesions on a CT scan. The examination was performed with an Acuson Sequoia (Siemens, Erlangen, Germany) with a low mechanical index (low MI) using the contrast agent imaging method "contrast pulsed sequencing" (CPS). We looked at the vascularization in the early phase (< 30 s) and the late phase (60 - 120 s). These findings were compared to the histopathological results.

RESULTS

25 (83 %) had an RCC, and two (7 %) patients showed an urothelial carcinoma. Benign tumors were diagnosed in three (10 %) patients. All of them were oncocytomas. In grayscale ultrasound 52 % of the RCCs were hypoechoic, 36 % isoechoic, and 12 % hyperechoic. After the application of the contrast agent, all RCCs showed a chaotic vascularization pattern. In the early phase (< 30 s), 12 tumors showed hyperperfusion, three showed isoperfusion, and nine showed hypoperfusion. During the late phase (60 - 120 s), five tumors showed hyperperfusion, nine showed isoperfusion, and ten showed hypoperfusion. One small cystic tumor did not indicate contrast enhancement at any time.

CONCLUSION

In our study RCC showed chaotic vascularization in CEUS without typical vascularization patterns.