To investigate the pathological features and prognostic value of renal tumor venous thrombus.

The clinical data of 55 cases of renal cell carcinoma with inferior vena cava tumor thrombus treated from January 2015 to January 2017 were collected and analyzed retrospectively, including 46 males and 9 females, with the mean age of 60 years (29-82 years), and the body mass index of 16.4-33.0 kg/m² (mean 24.2 kg/m²). Renal tumors are located on the right side of 37 cases and on the left side of 18 cases. The diameter of the tumor was 2.0-21.1 cm (mean 8.0 cm). Mayo classification were 13 cases of grade 0, 11 cases of grade Ⅰ, 19 cases of grade Ⅱ, 7 cases of grade Ⅲ, and 5 cases of grade Ⅳ. The patients′ paraffin pathology was reviewed and the classification, grade, nuclear grade, tumor composition, and vascular wall adhesion were recorded. All patients were followed up after surgery and the relationship between the characteristics and the prognosis was analyzed.

There were 47 cases of renal clear cell carcinoma and 8 cases of papillary renal cell carcinoma type 2. Nuclear grade was 4 cases of grade 1, 20 cases of grade 2, 25 cases of grade 3, and 6 cases of grade 4. There were 11 cases of large tumor necrosis, 6 cases of sarcoma, and 38 cases of focal or no necrosis. There were 20 cases of extensive blood vessels adhesion of cancer thrombus, and 35 cases of focal or no adhesion. Vascular adhesion was associated with pathological types and tumor types (P=0.021, P=0.036). The median follow-up duration was 17 months. The postoperative one-year survival rate was 87.3%. Overall survival was different in patients with different tumor types, vascular adhesion and nuclear grade, among which the overall survival rate (33.3%) of the sarcoma group was significantly lower than that of the non-necrotic group (84.8%, P=0.003) and large necrotic group (100.0%, P=0.002). Overall survival rate (65.0%) was significantly lower in the vascular extensive adhesion group than in the focal or non-adhesion group (94.3%, P=0.005). The survival rate decreased as nuclear grade increased, among which the overall survival rate of patients at level 1, 2, 3 and 4 were 100%, 95%, 80% and 50% respectively (P=0.045). There was no difference in survival among patients with different Mayo grading and pathological classification (P=0.426, P=0.604).

The pathology of tumor thrombus in renal cancer helps to predict prognosis. There is no significant difference in survival among patients with different pathological types and Mayo grades. Sarcoma, advanced tumor nuclear grade and vascular adhesion of tumor thrombus are adverse prognostic factors.

Kidney neoplasms; Tumor thrombus; Pathological features; Prognosis