**4. Preoperative targeted therapy**

Although mini-traumatic surgery has been applied in patients with RCC and tumor thrombus, level III and IV tumor thrombus might have lethal complications, including hemorrhage, thrombotic shedding, etc. The operative mortality and overall morbidity rates of postoperative complication of patients with tumor thrombus patients have been reported up to 5–10% and 38%, respectively [21]. Moreover, as tumor thrombus level advanced, the morbidity of perioperative periodical complications is higher accordingly. With regard to patients with level III and IV tumor thrombus, surgical strategies usually involve thoracotomy, dealing with retro- or superohepatic IVC, and establishing extracorporeal circulation, which can be achieved with the assistance of hepatobiliary and cardiovascular surgeons.

With the targeted molecular therapy (TMT) of rising, TMT has been widely acknowledged as the most effective treatment for advanced RCC, particularly for patients with metastatic RCC. In recent years, targeted drugs have been reported to be applied in preoperative adjunctive therapy for tumor thrombus because of its high success rate in the treatment of advanced RCC [22, 23]. The purpose of administering target drugs was to lessen the height of tumor thrombus or shrink the primary lesions or metastases, which may enhance the safety and feasibility of surgical intervention. The results of some retrospective observations with a small sample present diversities [24–26]. After preoperative TMT, 44–76% of the patients' IVC tumor thrombus had shrinkage in different degrees, with tumor thrombus degradation averaging approximately 20%. Cost and colleagues reported a retrospective outcome from a sample of 25 patients, wherein three patients (12%) had a reduction in the thrombus degradation, and one patient (4%) had an increase [25]. As a result of first-class evidence deficiency, this therapeutic regimen has not been recommended by the guidelines. Thus, further prospective investigations with a larger number of patients are needed to overcome the limitations.
