In patients with renal cell carcinoma with tumor thrombus involving the inferior vena cava (IVC), the standard of care remains surgical resection through radical nephrectomy with IVC tumor thrombectomy. Among patients with levels I through IV caval thrombi, management of the IVC at the time of tumor thrombectomy entails varying degrees of reconstruction, ranging from a primary IVC closure to complex vascular reconstruction with either a patch graft or tube interposition graft, to complete resection of a portion of the IVC, often necessitating collaboration the vascular surgery team.
Ultimately, the management of the IVC is determined at the time of resection, when the extent of the thrombus and its relative invasiveness or adherence to the endothelium is fully appreciated, and when the surgeon is able to assess the degree of vascular resection necessary to obtain a complete resection.
The ability to predict the need for IVC resection preoperatively would be advantageous in terms of optimizing preoperative consent, preparation, and safety, and maximizing resource utilization in the OR for patients with tumor thrombus. The objective of our study, therefore, was to evaluate the prognostic value of preoperative clinical and radiographic features, which may be used to identify patients at the highest risk of needing complex vascular resection and reconstruction at the time of tumor thrombectomy.
The preoperative imaging (either MRI or CT scans) of 172 patients with levels I – IV tumor thrombi who underwent radical nephrectomy with tumor thrombectomy between 2000 and 2010 was evaluated for a-priori determined radiographic features by two radiologists blinded to the surgical outcomes of the patients. Univariable and multivariable models were then developed to detect associations between preoperative radiographic measurements and the need for complex IVC resection at the time of the tumor thrombectomy necessitating one or more of the following complex vascular procedures: vascular patch graft, tube interposition graft, or complete division or resection of the IVC. In total, 38 of the patients required one or more of these complex vascular procedures.
We found that the presence of a right-sided tumor, an IVC diameter at the level of renal vein ostium greater than or equal to 24 mm, or the presence of complete occlusion of the IVC at the level of the renal vein ostium were each independently associated with the need for complex vascular resection and reconstruction on multivariable modeling. We found that if a patient had all three features, there was a 64% probability of the need for extensive vascular resection. On the other hand, if none of these features were present, the risk of a patient requiring complex IVC resection at the time of tumor thrombectomy was only 2%.
Our study represents a single high-volume academic institution’s experience, reviewed retrospectively. As such, the results may have been influenced by selection bias and practice patterns. Therefore, further prospective study and external validation is necessary.
However, this study represents the largest study to date to assess the prognostic value of objective, quantifiable, and easily measurable radiographic features that may be discerned from standard preoperative imaging in the tumor thrombus patient. Pending validation, the baseline clinical and radiographic features identified herein may assist urologists in identifying patients necessitating technically complex management of tumor thrombi in the preoperative setting. These findings may augment a surgeon’s gestalt impression regarding the need to request early involvement of vascular surgical colleagues, thus optimizing resource utilization, as well as having implications for improving the safety and efficiency of IVC tumor thrombectomy.
Written by:
Sarah P. Psutka and Bradley C. Leibovich
Department of Urology, Mayo Clinic, Rochester, Minnesota.