Impact of venous tumour thrombus consistency (solid vs friable) on cancer-specific survival in patients with renal cell carcinoma

Background: To our knowledge, the impact of venous tumour thrombus (VTT) consistency in patients affected by renal cell carcinoma (RCC) has never been addressed. Objective: To analyse the effect of VTT consistency on cancer-specific survival (CSS). Design, setting, and participants: We retrospectively analysed 174 consecutive patients with RCC and renal vein or inferior vena cava (IVC) VTT who underwent surgical treatment between 1989 and 2007 at our institute. Intervention: All patients underwent radical nephrectomy and thrombectomy. Measurements: Pathologic specimens were reviewed by a single uropathologist. In addition to traditional pathologic features, the morphologic aspect of the tumour thrombus was evaluated to distinguish solid from friable patterns. The prognostic role of thrombus consistency (solid vs friable) on CSS was assessed by means of Cox regression models. Results and limitations: The VTT was solid in 107 patients (61.5%) and friable in 67 patients (38.5%). The presence of a friable VTT increased the risk of having synchronous nodal or distant metastases, higher tumour grade, higher pathologic stage, and simultaneous perinephric fat invasion (all p < 0.05). The median follow-up was 24 mo. The median CSS was 33 mo; the median CSS was 8 mo in patients with a friable VTT and 55 mo in patients with a solid VTT (p < 0.001). On multivariable analyses, the presence of a friable VTT was an independent predictor of CSS (p = 0.02). The power of our conclusion may be somewhat limited by the relatively small study population and the retrospective nature of the study. Conclusions: In patients with RCC and VTT, the presence of a friable thrombus is an independent predictor of CSS. If our finding is confirmed by further studies, the consistency of the tumour thrombus should be introduced into routine pathologic reports to provide better patient risk stratification