Hepatectomy with concomitant resection of the inferior vena cava (IVC) has become common for hepatic malignancies involving the IVC. However, diagnosing IVC invasion and the procedure of choice have yet to be standardized. Medical records of nine patients with liver cancer (five metastatic tumors from colorectal cancer and four intrahepatic cholangiocarcinomas) believed to have directly invaded the IVC wall were retrospectively abstracted for data on preoperative radiologic studies, surgical procedures, histology of the resected specimen, and treatment outcome. All nine patients underwent hepatectomy: Five did not undergo IVC resection because the IVC could be isolated from the tumor; the remaining four underwent combined IVC resection (wedge and segmental resections in two each). The segmentally resected IVC was reconstructed using an external iliac vein graft. Total hepatic vascular exclusion, venovenous bypass, and the ex vivo technique were not used. Interestingly, the tumor was smaller and the percentage of the IVC circumference in contact with tumor as seen on computed tomography (CT) was less in patients with IVC invasion than in those without it (40 +/- 11 vs. 134 +/- 61 mm, p < 0.05; 30% +/- 8% vs. 60% +/- 20%, p < 0.05). The length of the IVC compressed by tumor on cavography was similar in the two patient groups (47 +/- 9 vs. 55 +/- 8 mm). All patients were discharged from the hospital in good condition: Seven died of cancer recurrence, and the remaining two are currently alive and disease-free 15 and 73 months after surgery, respectively. In conclusion, imaging modalities demonstrating caval deformation, such as CT and cavography, are unreliable for diagnosing direct invasion of the IVC wall. Even when IVC invasion is strongly suggested by conventional radiologic studies, the surgeon should endeavor to peel the tumor from the IVC. This strategy is important to avoid unnecessary resection of the IVC, use of a prosthetic graft, or ex vivo hepatectomy.